Operator Product on Locally Symmetric Spaces of Rank One and the Multiplicative Anomaly
EKI-1751-AE VDSL2 Ethernet扩展器启动手册说明书
EKI-1751-A EVDSL2 Ethernet Extender1 Startup ManualBefore installation, please make sure that you have received the following:▪ 1 x EKI-1751-AE VDSL Ethernet Extender ▪ 1 x Power Adapt e r▪ 1 x DIN-rail Mounting Bracket and Screws ▪ 1 x EKI-1751-AE Startup ManualIf anything is missing or damaged, contact your distributor or sales representative immediately. For more detailed information, please refer to the full manualwhich can be found on the Advantech’s website.General▪ I/O Port: 1 x 10/100Base-T(X) RJ-45 1 x VDSL2 Extender RJ-45 ▪ Power Connecto r: 2.1mm DC Jack▪ DIP Switch :Pin 1: Selectable CO or CPE mode▪LED Indicators: Port LED : Link / Speed / Activity▪ Power Input : 12V DC , 1A, External Power Adapter ▪ Power Consumption: 4.2 Watts▪Dimensions (W x H x D): 72.5 x 23 x 94.5 mm (2.85" x 0.91" x 3.72") ▪ Enclosure: IP30 ▪ OperatingTemperature: 0 ~ 45°C (32 ~ 113°F) ▪ Storage Temperature: -40 ~ 70°C (-40°F ~ 158°F) ▪Operating Humidity: 0 ~ 95% (non-condensing) ▪ Storage Humidity: 0 ~ 95% (non-condensing) ▪ Safety: UL60950 ▪ EMC: CE, FCC ▪Warranty: 5 yearsFor more information on this and other Advantech products, please visit our websites at: /products/For technical support and service: /support/ This startup manual is for EKI-1751-AE1st Edition Mar 2018The EKI-1751-AE is a Long Reach Ethernet Extender to utilize existing copper cabling infrastructure(twisted pair), extending Ethernet to up to 1200 meters over VDSL2. Applications such as IP-based Internet connections, video surveillance and voice services can benefit from the EKI-1751-AE . The devices support VDSL2 Profiles 17a and 30a.EKI-1751-AE is designed to work in pairs, over twisted pair; as an unmanaged product, it is easy to install and each Extender can be set to a Master (CO) or Remote (CPE) via a DIP Switch. Offering one model that can be set to a Master or Remote and operate as a pair reduces the cost of investment and minimizes inventory as well.The Extenders support SNR Margin, VDSL2 Profile 30a(High Bandwidth Mode) or VDSL2 Profile 17a (Long Reach Mode), and Symmetric/Asymmetric data throughput, all DIP Switch-selectable. The selection of symmetrical or asymmetrical for throughput ofupstream/downstream data rates directly influences the distance covered. LEDs include link activity, VDSL status, and Central Office or Customer Premises Equipment designation.The Extenders meet 802.3 Ethernet standards, as well as transparently supporting VLANS, 802.1q.Pin 2: Selectable 30a or 17a (VDSL2 Profile)Pin 3: Selectable Band plan (Symmetric or Asymmetric)Pin 4: electable target SNR margin (6dB or 9dB)System LED : PWROverviewLEDs for LAN12 Vdc in over 2.1mm DC Jack. (External Power Adaptor included)2DIP 1 DIP2 DIP3 DIP4Side VDSL2 Profile Rate Limit SNROFF OT 30a Symmetric 9dBON RT 17a Asymmetric 6dBDIP 1:OT:RT:LAN Extender acts as Customer Premise Equipment (CPE)side.DIP 2:30a:VDSL2 High Speed Mode.17a:VDSL2 Long Reach Mode.DIP 3:Symmetric:Support the band plan G.997 and provide the symmetrictransmission on both downstream and upstream.Asymmetric:Provides highest line rate in short range in asymmetricmode.DIP 4:9dB:Better channel noise protection with SNR up to 9 dB.6dB:Original channel noise protection with 6 dB SNR.2STEP 1:Set the LAN extender to CO mode orCPE mode from the DIP switch at thefront panel. For Point to PointSTEP 2:STEP 3:STEP 4:STEP 5:STEP 6:connecting the power adapter and thenobserve the status of VDSL2 link LED.Setting as CO side Setting as CPE sideStartup Manual 2。
lecture7_Product Operator Formalism
aa a a
=I x E E S x
0 i 1 Fy I y S y 2 1 0
-1 0 0 1
-1 0 0 1
0 -1 -1 0
1 0 Fz I z S z 0 0
0 0 0 0
0 0 0 0
0 0 0 -1
Density Matrix
c 1 c 2 c n * * * c2 cn c1 I 11 I I xA 21 I n1
I12 I1n I 22 I 2n I n2 I nn
where d mn c m c* n
and
d nm d* mn
Thus, the Density Matrix is Hermitian.
Density Matrix
Now the macroscopic magnetization can be written in terms of the Density Matrix:
Ix a
1 1 0 1 0 1 1 2 1 0 0 2 1 2
0 1 1 1 0 1 1 a Ix 2 1 0 1 2 0 2 1 1 0 1 0 i 1 i Iy a 2 i 0 0 2 i 2
Considering one nucleus, A, the expectation value for the magnetic moment is:
<µ xA> = <|µ xA|> = gA<|IxA|> IxA is the operator of the x-component of the angular momentum. Considering an ensemble of spins: Mx = No<µ xA> = NogA<|IxA|> where No is the number of spins in a particular volume. As we have discussed, the wavefunction can be expressed as a linear combination of eigenfunctions, so that we can place <|IxA|> in matrix form.
机器学习专业词汇中英文对照
机器学习专业词汇中英⽂对照activation 激活值activation function 激活函数additive noise 加性噪声autoencoder ⾃编码器Autoencoders ⾃编码算法average firing rate 平均激活率average sum-of-squares error 均⽅差backpropagation 后向传播basis 基basis feature vectors 特征基向量batch gradient ascent 批量梯度上升法Bayesian regularization method 贝叶斯规则化⽅法Bernoulli random variable 伯努利随机变量bias term 偏置项binary classfication ⼆元分类class labels 类型标记concatenation 级联conjugate gradient 共轭梯度contiguous groups 联通区域convex optimization software 凸优化软件convolution 卷积cost function 代价函数covariance matrix 协⽅差矩阵DC component 直流分量decorrelation 去相关degeneracy 退化demensionality reduction 降维derivative 导函数diagonal 对⾓线diffusion of gradients 梯度的弥散eigenvalue 特征值eigenvector 特征向量error term 残差feature matrix 特征矩阵feature standardization 特征标准化feedforward architectures 前馈结构算法feedforward neural network 前馈神经⽹络feedforward pass 前馈传导fine-tuned 微调first-order feature ⼀阶特征forward pass 前向传导forward propagation 前向传播Gaussian prior ⾼斯先验概率generative model ⽣成模型gradient descent 梯度下降Greedy layer-wise training 逐层贪婪训练⽅法grouping matrix 分组矩阵Hadamard product 阿达马乘积Hessian matrix Hessian 矩阵hidden layer 隐含层hidden units 隐藏神经元Hierarchical grouping 层次型分组higher-order features 更⾼阶特征highly non-convex optimization problem ⾼度⾮凸的优化问题histogram 直⽅图hyperbolic tangent 双曲正切函数hypothesis 估值,假设identity activation function 恒等激励函数IID 独⽴同分布illumination 照明inactive 抑制independent component analysis 独⽴成份分析input domains 输⼊域input layer 输⼊层intensity 亮度/灰度intercept term 截距KL divergence 相对熵KL divergence KL分散度k-Means K-均值learning rate 学习速率least squares 最⼩⼆乘法linear correspondence 线性响应linear superposition 线性叠加line-search algorithm 线搜索算法local mean subtraction 局部均值消减local optima 局部最优解logistic regression 逻辑回归loss function 损失函数low-pass filtering 低通滤波magnitude 幅值MAP 极⼤后验估计maximum likelihood estimation 极⼤似然估计mean 平均值MFCC Mel 倒频系数multi-class classification 多元分类neural networks 神经⽹络neuron 神经元Newton’s method ⽜顿法non-convex function ⾮凸函数non-linear feature ⾮线性特征norm 范式norm bounded 有界范数norm constrained 范数约束normalization 归⼀化numerical roundoff errors 数值舍⼊误差numerically checking 数值检验numerically reliable 数值计算上稳定object detection 物体检测objective function ⽬标函数off-by-one error 缺位错误orthogonalization 正交化output layer 输出层overall cost function 总体代价函数over-complete basis 超完备基over-fitting 过拟合parts of objects ⽬标的部件part-whole decompostion 部分-整体分解PCA 主元分析penalty term 惩罚因⼦per-example mean subtraction 逐样本均值消减pooling 池化pretrain 预训练principal components analysis 主成份分析quadratic constraints ⼆次约束RBMs 受限Boltzman机reconstruction based models 基于重构的模型reconstruction cost 重建代价reconstruction term 重构项redundant 冗余reflection matrix 反射矩阵regularization 正则化regularization term 正则化项rescaling 缩放robust 鲁棒性run ⾏程second-order feature ⼆阶特征sigmoid activation function S型激励函数significant digits 有效数字singular value 奇异值singular vector 奇异向量smoothed L1 penalty 平滑的L1范数惩罚Smoothed topographic L1 sparsity penalty 平滑地形L1稀疏惩罚函数smoothing 平滑Softmax Regresson Softmax回归sorted in decreasing order 降序排列source features 源特征sparse autoencoder 消减归⼀化Sparsity 稀疏性sparsity parameter 稀疏性参数sparsity penalty 稀疏惩罚square function 平⽅函数squared-error ⽅差stationary 平稳性(不变性)stationary stochastic process 平稳随机过程step-size 步长值supervised learning 监督学习symmetric positive semi-definite matrix 对称半正定矩阵symmetry breaking 对称失效tanh function 双曲正切函数the average activation 平均活跃度the derivative checking method 梯度验证⽅法the empirical distribution 经验分布函数the energy function 能量函数the Lagrange dual 拉格朗⽇对偶函数the log likelihood 对数似然函数the pixel intensity value 像素灰度值the rate of convergence 收敛速度topographic cost term 拓扑代价项topographic ordered 拓扑秩序transformation 变换translation invariant 平移不变性trivial answer 平凡解under-complete basis 不完备基unrolling 组合扩展unsupervised learning ⽆监督学习variance ⽅差vecotrized implementation 向量化实现vectorization ⽮量化visual cortex 视觉⽪层weight decay 权重衰减weighted average 加权平均值whitening ⽩化zero-mean 均值为零Letter AAccumulated error backpropagation 累积误差逆传播Activation Function 激活函数Adaptive Resonance Theory/ART ⾃适应谐振理论Addictive model 加性学习Adversarial Networks 对抗⽹络Affine Layer 仿射层Affinity matrix 亲和矩阵Agent 代理 / 智能体Algorithm 算法Alpha-beta pruning α-β剪枝Anomaly detection 异常检测Approximation 近似Area Under ROC Curve/AUC Roc 曲线下⾯积Artificial General Intelligence/AGI 通⽤⼈⼯智能Artificial Intelligence/AI ⼈⼯智能Association analysis 关联分析Attention mechanism 注意⼒机制Attribute conditional independence assumption 属性条件独⽴性假设Attribute space 属性空间Attribute value 属性值Autoencoder ⾃编码器Automatic speech recognition ⾃动语⾳识别Automatic summarization ⾃动摘要Average gradient 平均梯度Average-Pooling 平均池化Letter BBackpropagation Through Time 通过时间的反向传播Backpropagation/BP 反向传播Base learner 基学习器Base learning algorithm 基学习算法Batch Normalization/BN 批量归⼀化Bayes decision rule 贝叶斯判定准则Bayes Model Averaging/BMA 贝叶斯模型平均Bayes optimal classifier 贝叶斯最优分类器Bayesian decision theory 贝叶斯决策论Bayesian network 贝叶斯⽹络Between-class scatter matrix 类间散度矩阵Bias 偏置 / 偏差Bias-variance decomposition 偏差-⽅差分解Bias-Variance Dilemma 偏差 – ⽅差困境Bi-directional Long-Short Term Memory/Bi-LSTM 双向长短期记忆Binary classification ⼆分类Binomial test ⼆项检验Bi-partition ⼆分法Boltzmann machine 玻尔兹曼机Bootstrap sampling ⾃助采样法/可重复采样/有放回采样Bootstrapping ⾃助法Break-Event Point/BEP 平衡点Letter CCalibration 校准Cascade-Correlation 级联相关Categorical attribute 离散属性Class-conditional probability 类条件概率Classification and regression tree/CART 分类与回归树Classifier 分类器Class-imbalance 类别不平衡Closed -form 闭式Cluster 簇/类/集群Cluster analysis 聚类分析Clustering 聚类Clustering ensemble 聚类集成Co-adapting 共适应Coding matrix 编码矩阵COLT 国际学习理论会议Committee-based learning 基于委员会的学习Competitive learning 竞争型学习Component learner 组件学习器Comprehensibility 可解释性Computation Cost 计算成本Computational Linguistics 计算语⾔学Computer vision 计算机视觉Concept drift 概念漂移Concept Learning System /CLS 概念学习系统Conditional entropy 条件熵Conditional mutual information 条件互信息Conditional Probability Table/CPT 条件概率表Conditional random field/CRF 条件随机场Conditional risk 条件风险Confidence 置信度Confusion matrix 混淆矩阵Connection weight 连接权Connectionism 连结主义Consistency ⼀致性/相合性Contingency table 列联表Continuous attribute 连续属性Convergence 收敛Conversational agent 会话智能体Convex quadratic programming 凸⼆次规划Convexity 凸性Convolutional neural network/CNN 卷积神经⽹络Co-occurrence 同现Correlation coefficient 相关系数Cosine similarity 余弦相似度Cost curve 成本曲线Cost Function 成本函数Cost matrix 成本矩阵Cost-sensitive 成本敏感Cross entropy 交叉熵Cross validation 交叉验证Crowdsourcing 众包Curse of dimensionality 维数灾难Cut point 截断点Cutting plane algorithm 割平⾯法Letter DData mining 数据挖掘Data set 数据集Decision Boundary 决策边界Decision stump 决策树桩Decision tree 决策树/判定树Deduction 演绎Deep Belief Network 深度信念⽹络Deep Convolutional Generative Adversarial Network/DCGAN 深度卷积⽣成对抗⽹络Deep learning 深度学习Deep neural network/DNN 深度神经⽹络Deep Q-Learning 深度 Q 学习Deep Q-Network 深度 Q ⽹络Density estimation 密度估计Density-based clustering 密度聚类Differentiable neural computer 可微分神经计算机Dimensionality reduction algorithm 降维算法Directed edge 有向边Disagreement measure 不合度量Discriminative model 判别模型Discriminator 判别器Distance measure 距离度量Distance metric learning 距离度量学习Distribution 分布Divergence 散度Diversity measure 多样性度量/差异性度量Domain adaption 领域⾃适应Downsampling 下采样D-separation (Directed separation)有向分离Dual problem 对偶问题Dummy node 哑结点Dynamic Fusion 动态融合Dynamic programming 动态规划Letter EEigenvalue decomposition 特征值分解Embedding 嵌⼊Emotional analysis 情绪分析Empirical conditional entropy 经验条件熵Empirical entropy 经验熵Empirical error 经验误差Empirical risk 经验风险End-to-End 端到端Energy-based model 基于能量的模型Ensemble learning 集成学习Ensemble pruning 集成修剪Error Correcting Output Codes/ECOC 纠错输出码Error rate 错误率Error-ambiguity decomposition 误差-分歧分解Euclidean distance 欧⽒距离Evolutionary computation 演化计算Expectation-Maximization 期望最⼤化Expected loss 期望损失Exploding Gradient Problem 梯度爆炸问题Exponential loss function 指数损失函数Extreme Learning Machine/ELM 超限学习机Letter FFactorization 因⼦分解False negative 假负类False positive 假正类False Positive Rate/FPR 假正例率Feature engineering 特征⼯程Feature selection 特征选择Feature vector 特征向量Featured Learning 特征学习Feedforward Neural Networks/FNN 前馈神经⽹络Fine-tuning 微调Flipping output 翻转法Fluctuation 震荡Forward stagewise algorithm 前向分步算法Frequentist 频率主义学派Full-rank matrix 满秩矩阵Functional neuron 功能神经元Letter GGain ratio 增益率Game theory 博弈论Gaussian kernel function ⾼斯核函数Gaussian Mixture Model ⾼斯混合模型General Problem Solving 通⽤问题求解Generalization 泛化Generalization error 泛化误差Generalization error bound 泛化误差上界Generalized Lagrange function ⼴义拉格朗⽇函数Generalized linear model ⼴义线性模型Generalized Rayleigh quotient ⼴义瑞利商Generative Adversarial Networks/GAN ⽣成对抗⽹络Generative Model ⽣成模型Generator ⽣成器Genetic Algorithm/GA 遗传算法Gibbs sampling 吉布斯采样Gini index 基尼指数Global minimum 全局最⼩Global Optimization 全局优化Gradient boosting 梯度提升Gradient Descent 梯度下降Graph theory 图论Ground-truth 真相/真实Letter HHard margin 硬间隔Hard voting 硬投票Harmonic mean 调和平均Hesse matrix 海塞矩阵Hidden dynamic model 隐动态模型Hidden layer 隐藏层Hidden Markov Model/HMM 隐马尔可夫模型Hierarchical clustering 层次聚类Hilbert space 希尔伯特空间Hinge loss function 合页损失函数Hold-out 留出法Homogeneous 同质Hybrid computing 混合计算Hyperparameter 超参数Hypothesis 假设Hypothesis test 假设验证Letter IICML 国际机器学习会议Improved iterative scaling/IIS 改进的迭代尺度法Incremental learning 增量学习Independent and identically distributed/i.i.d. 独⽴同分布Independent Component Analysis/ICA 独⽴成分分析Indicator function 指⽰函数Individual learner 个体学习器Induction 归纳Inductive bias 归纳偏好Inductive learning 归纳学习Inductive Logic Programming/ILP 归纳逻辑程序设计Information entropy 信息熵Information gain 信息增益Input layer 输⼊层Insensitive loss 不敏感损失Inter-cluster similarity 簇间相似度International Conference for Machine Learning/ICML 国际机器学习⼤会Intra-cluster similarity 簇内相似度Intrinsic value 固有值Isometric Mapping/Isomap 等度量映射Isotonic regression 等分回归Iterative Dichotomiser 迭代⼆分器Letter KKernel method 核⽅法Kernel trick 核技巧Kernelized Linear Discriminant Analysis/KLDA 核线性判别分析K-fold cross validation k 折交叉验证/k 倍交叉验证K-Means Clustering K – 均值聚类K-Nearest Neighbours Algorithm/KNN K近邻算法Knowledge base 知识库Knowledge Representation 知识表征Letter LLabel space 标记空间Lagrange duality 拉格朗⽇对偶性Lagrange multiplier 拉格朗⽇乘⼦Laplace smoothing 拉普拉斯平滑Laplacian correction 拉普拉斯修正Latent Dirichlet Allocation 隐狄利克雷分布Latent semantic analysis 潜在语义分析Latent variable 隐变量Lazy learning 懒惰学习Learner 学习器Learning by analogy 类⽐学习Learning rate 学习率Learning Vector Quantization/LVQ 学习向量量化Least squares regression tree 最⼩⼆乘回归树Leave-One-Out/LOO 留⼀法linear chain conditional random field 线性链条件随机场Linear Discriminant Analysis/LDA 线性判别分析Linear model 线性模型Linear Regression 线性回归Link function 联系函数Local Markov property 局部马尔可夫性Local minimum 局部最⼩Log likelihood 对数似然Log odds/logit 对数⼏率Logistic Regression Logistic 回归Log-likelihood 对数似然Log-linear regression 对数线性回归Long-Short Term Memory/LSTM 长短期记忆Loss function 损失函数Letter MMachine translation/MT 机器翻译Macron-P 宏查准率Macron-R 宏查全率Majority voting 绝对多数投票法Manifold assumption 流形假设Manifold learning 流形学习Margin theory 间隔理论Marginal distribution 边际分布Marginal independence 边际独⽴性Marginalization 边际化Markov Chain Monte Carlo/MCMC 马尔可夫链蒙特卡罗⽅法Markov Random Field 马尔可夫随机场Maximal clique 最⼤团Maximum Likelihood Estimation/MLE 极⼤似然估计/极⼤似然法Maximum margin 最⼤间隔Maximum weighted spanning tree 最⼤带权⽣成树Max-Pooling 最⼤池化Mean squared error 均⽅误差Meta-learner 元学习器Metric learning 度量学习Micro-P 微查准率Micro-R 微查全率Minimal Description Length/MDL 最⼩描述长度Minimax game 极⼩极⼤博弈Misclassification cost 误分类成本Mixture of experts 混合专家Momentum 动量Moral graph 道德图/端正图Multi-class classification 多分类Multi-document summarization 多⽂档摘要Multi-layer feedforward neural networks 多层前馈神经⽹络Multilayer Perceptron/MLP 多层感知器Multimodal learning 多模态学习Multiple Dimensional Scaling 多维缩放Multiple linear regression 多元线性回归Multi-response Linear Regression /MLR 多响应线性回归Mutual information 互信息Letter NNaive bayes 朴素贝叶斯Naive Bayes Classifier 朴素贝叶斯分类器Named entity recognition 命名实体识别Nash equilibrium 纳什均衡Natural language generation/NLG ⾃然语⾔⽣成Natural language processing ⾃然语⾔处理Negative class 负类Negative correlation 负相关法Negative Log Likelihood 负对数似然Neighbourhood Component Analysis/NCA 近邻成分分析Neural Machine Translation 神经机器翻译Neural Turing Machine 神经图灵机Newton method ⽜顿法NIPS 国际神经信息处理系统会议No Free Lunch Theorem/NFL 没有免费的午餐定理Noise-contrastive estimation 噪⾳对⽐估计Nominal attribute 列名属性Non-convex optimization ⾮凸优化Nonlinear model ⾮线性模型Non-metric distance ⾮度量距离Non-negative matrix factorization ⾮负矩阵分解Non-ordinal attribute ⽆序属性Non-Saturating Game ⾮饱和博弈Norm 范数Normalization 归⼀化Nuclear norm 核范数Numerical attribute 数值属性Letter OObjective function ⽬标函数Oblique decision tree 斜决策树Occam’s razor 奥卡姆剃⼑Odds ⼏率Off-Policy 离策略One shot learning ⼀次性学习One-Dependent Estimator/ODE 独依赖估计On-Policy 在策略Ordinal attribute 有序属性Out-of-bag estimate 包外估计Output layer 输出层Output smearing 输出调制法Overfitting 过拟合/过配Oversampling 过采样Letter PPaired t-test 成对 t 检验Pairwise 成对型Pairwise Markov property 成对马尔可夫性Parameter 参数Parameter estimation 参数估计Parameter tuning 调参Parse tree 解析树Particle Swarm Optimization/PSO 粒⼦群优化算法Part-of-speech tagging 词性标注Perceptron 感知机Performance measure 性能度量Plug and Play Generative Network 即插即⽤⽣成⽹络Plurality voting 相对多数投票法Polarity detection 极性检测Polynomial kernel function 多项式核函数Pooling 池化Positive class 正类Positive definite matrix 正定矩阵Post-hoc test 后续检验Post-pruning 后剪枝potential function 势函数Precision 查准率/准确率Prepruning 预剪枝Principal component analysis/PCA 主成分分析Principle of multiple explanations 多释原则Prior 先验Probability Graphical Model 概率图模型Proximal Gradient Descent/PGD 近端梯度下降Pruning 剪枝Pseudo-label 伪标记Letter QQuantized Neural Network 量⼦化神经⽹络Quantum computer 量⼦计算机Quantum Computing 量⼦计算Quasi Newton method 拟⽜顿法Letter RRadial Basis Function/RBF 径向基函数Random Forest Algorithm 随机森林算法Random walk 随机漫步Recall 查全率/召回率Receiver Operating Characteristic/ROC 受试者⼯作特征Rectified Linear Unit/ReLU 线性修正单元Recurrent Neural Network 循环神经⽹络Recursive neural network 递归神经⽹络Reference model 参考模型Regression 回归Regularization 正则化Reinforcement learning/RL 强化学习Representation learning 表征学习Representer theorem 表⽰定理reproducing kernel Hilbert space/RKHS 再⽣核希尔伯特空间Re-sampling 重采样法Rescaling 再缩放Residual Mapping 残差映射Residual Network 残差⽹络Restricted Boltzmann Machine/RBM 受限玻尔兹曼机Restricted Isometry Property/RIP 限定等距性Re-weighting 重赋权法Robustness 稳健性/鲁棒性Root node 根结点Rule Engine 规则引擎Rule learning 规则学习Letter SSaddle point 鞍点Sample space 样本空间Sampling 采样Score function 评分函数Self-Driving ⾃动驾驶Self-Organizing Map/SOM ⾃组织映射Semi-naive Bayes classifiers 半朴素贝叶斯分类器Semi-Supervised Learning 半监督学习semi-Supervised Support Vector Machine 半监督⽀持向量机Sentiment analysis 情感分析Separating hyperplane 分离超平⾯Sigmoid function Sigmoid 函数Similarity measure 相似度度量Simulated annealing 模拟退⽕Simultaneous localization and mapping 同步定位与地图构建Singular Value Decomposition 奇异值分解Slack variables 松弛变量Smoothing 平滑Soft margin 软间隔Soft margin maximization 软间隔最⼤化Soft voting 软投票Sparse representation 稀疏表征Sparsity 稀疏性Specialization 特化Spectral Clustering 谱聚类Speech Recognition 语⾳识别Splitting variable 切分变量Squashing function 挤压函数Stability-plasticity dilemma 可塑性-稳定性困境Statistical learning 统计学习Status feature function 状态特征函Stochastic gradient descent 随机梯度下降Stratified sampling 分层采样Structural risk 结构风险Structural risk minimization/SRM 结构风险最⼩化Subspace ⼦空间Supervised learning 监督学习/有导师学习support vector expansion ⽀持向量展式Support Vector Machine/SVM ⽀持向量机Surrogat loss 替代损失Surrogate function 替代函数Symbolic learning 符号学习Symbolism 符号主义Synset 同义词集Letter TT-Distribution Stochastic Neighbour Embedding/t-SNE T – 分布随机近邻嵌⼊Tensor 张量Tensor Processing Units/TPU 张量处理单元The least square method 最⼩⼆乘法Threshold 阈值Threshold logic unit 阈值逻辑单元Threshold-moving 阈值移动Time Step 时间步骤Tokenization 标记化Training error 训练误差Training instance 训练⽰例/训练例Transductive learning 直推学习Transfer learning 迁移学习Treebank 树库Tria-by-error 试错法True negative 真负类True positive 真正类True Positive Rate/TPR 真正例率Turing Machine 图灵机Twice-learning ⼆次学习Letter UUnderfitting ⽋拟合/⽋配Undersampling ⽋采样Understandability 可理解性Unequal cost ⾮均等代价Unit-step function 单位阶跃函数Univariate decision tree 单变量决策树Unsupervised learning ⽆监督学习/⽆导师学习Unsupervised layer-wise training ⽆监督逐层训练Upsampling 上采样Letter VVanishing Gradient Problem 梯度消失问题Variational inference 变分推断VC Theory VC维理论Version space 版本空间Viterbi algorithm 维特⽐算法Von Neumann architecture 冯 · 诺伊曼架构Letter WWasserstein GAN/WGAN Wasserstein⽣成对抗⽹络Weak learner 弱学习器Weight 权重Weight sharing 权共享Weighted voting 加权投票法Within-class scatter matrix 类内散度矩阵Word embedding 词嵌⼊Word sense disambiguation 词义消歧Letter ZZero-data learning 零数据学习Zero-shot learning 零次学习Aapproximations近似值arbitrary随意的affine仿射的arbitrary任意的amino acid氨基酸amenable经得起检验的axiom公理,原则abstract提取architecture架构,体系结构;建造业absolute绝对的arsenal军⽕库assignment分配algebra线性代数asymptotically⽆症状的appropriate恰当的Bbias偏差brevity简短,简洁;短暂broader⼴泛briefly简短的batch批量Cconvergence 收敛,集中到⼀点convex凸的contours轮廓constraint约束constant常理commercial商务的complementarity补充coordinate ascent同等级上升clipping剪下物;剪报;修剪component分量;部件continuous连续的covariance协⽅差canonical正规的,正则的concave⾮凸的corresponds相符合;相当;通信corollary推论concrete具体的事物,实在的东西cross validation交叉验证correlation相互关系convention约定cluster⼀簇centroids 质⼼,形⼼converge收敛computationally计算(机)的calculus计算Dderive获得,取得dual⼆元的duality⼆元性;⼆象性;对偶性derivation求导;得到;起源denote预⽰,表⽰,是…的标志;意味着,[逻]指称divergence 散度;发散性dimension尺度,规格;维数dot⼩圆点distortion变形density概率密度函数discrete离散的discriminative有识别能⼒的diagonal对⾓dispersion分散,散开determinant决定因素disjoint不相交的Eencounter遇到ellipses椭圆equality等式extra额外的empirical经验;观察ennmerate例举,计数exceed超过,越出expectation期望efficient⽣效的endow赋予explicitly清楚的exponential family指数家族equivalently等价的Ffeasible可⾏的forary初次尝试finite有限的,限定的forgo摒弃,放弃fliter过滤frequentist最常发⽣的forward search前向式搜索formalize使定形Ggeneralized归纳的generalization概括,归纳;普遍化;判断(根据不⾜)guarantee保证;抵押品generate形成,产⽣geometric margins⼏何边界gap裂⼝generative⽣产的;有⽣产⼒的Hheuristic启发式的;启发法;启发程序hone怀恋;磨hyperplane超平⾯Linitial最初的implement执⾏intuitive凭直觉获知的incremental增加的intercept截距intuitious直觉instantiation例⼦indicator指⽰物,指⽰器interative重复的,迭代的integral积分identical相等的;完全相同的indicate表⽰,指出invariance不变性,恒定性impose把…强加于intermediate中间的interpretation解释,翻译Jjoint distribution联合概率Llieu替代logarithmic对数的,⽤对数表⽰的latent潜在的Leave-one-out cross validation留⼀法交叉验证Mmagnitude巨⼤mapping绘图,制图;映射matrix矩阵mutual相互的,共同的monotonically单调的minor较⼩的,次要的multinomial多项的multi-class classification⼆分类问题Nnasty讨厌的notation标志,注释naïve朴素的Oobtain得到oscillate摆动optimization problem最优化问题objective function⽬标函数optimal最理想的orthogonal(⽮量,矩阵等)正交的orientation⽅向ordinary普通的occasionally偶然的Ppartial derivative偏导数property性质proportional成⽐例的primal原始的,最初的permit允许pseudocode伪代码permissible可允许的polynomial多项式preliminary预备precision精度perturbation 不安,扰乱poist假定,设想positive semi-definite半正定的parentheses圆括号posterior probability后验概率plementarity补充pictorially图像的parameterize确定…的参数poisson distribution柏松分布pertinent相关的Qquadratic⼆次的quantity量,数量;分量query疑问的Rregularization使系统化;调整reoptimize重新优化restrict限制;限定;约束reminiscent回忆往事的;提醒的;使⼈联想…的(of)remark注意random variable随机变量respect考虑respectively各⾃的;分别的redundant过多的;冗余的Ssusceptible敏感的stochastic可能的;随机的symmetric对称的sophisticated复杂的spurious假的;伪造的subtract减去;减法器simultaneously同时发⽣地;同步地suffice满⾜scarce稀有的,难得的split分解,分离subset⼦集statistic统计量successive iteratious连续的迭代scale标度sort of有⼏分的squares平⽅Ttrajectory轨迹temporarily暂时的terminology专⽤名词tolerance容忍;公差thumb翻阅threshold阈,临界theorem定理tangent正弦Uunit-length vector单位向量Vvalid有效的,正确的variance⽅差variable变量;变元vocabulary词汇valued经估价的;宝贵的Wwrapper包装分类:。
Canonical bases of q-deformed Fock spaces
where p(k) denotes the number of partitions λ of k. Hence it is not obvious to apply Kashiwara’s or Lusztig’s method to define a canonical basis of F . In this note, we shall rather regard F as a representation of the enlarged algebra gln . Indeed, F is a simple gln -module, and a q -deformation Fq of this representation has been described in [11]. One can then define a natural semi-linear involution v → v commuting with the action of the lowering operators of Fq and leaving invariant its highest weight vector. Using this involution, one obtains in an elementary way a canonical basis {G(λ)} of Fq . This basis can be computed explicitely. It would be interesting to compare it with the canonical basis obtained via a geometric approach by Ginzburg, Reshetikhin and Vasserot [7]. By restriction to Uq (sln ), the space Fq decomposes similarly as Fq ∼ =
Integrated density of states and Wegner estimates for random Schrodinger Operators
INTEGRATED DENSITY OF STATES AND WEGNER ESTIMATES
99
On the other hand, the electron could be moving in an amorphous medium, in which case there is no large group of symmetries of the Hamiltonian. However, from the physical point of view it is reasonable to assume that the local structure of the medium will be translation invariant on average. This means that we consider the potential which the electron experiences as a particular realisation of a random process and assume stationarity with respect to some group of translations. Moreover, physical intuition suggests to assume that the local properties of the medium in two regions far apart (on the microscopic scale) are approximately independent from each other. Therefore the stochastic process describing the potential should have a correlation function which decays to zero, or — more precisely — should be ergodic. There are interesting models which lie between the two extreme cases of latticeperiodic and amorphous media. They still have an underlying lattice structure which is, however, modified by disorder. Probably the best studied Hamiltonian with this properties is the alloy type model. We leave its precise definition for the next paragraph and introduce here a special case on the intuitive level. Consider first the potential Vω (x) := uk (ω, x) Each k corresponds to a nucleus sitting on a lattice point. The function uk (ω, ·) describes the atomic or nuclear potential at the site k and depends on the random parameter ω which models the different realisations of the configuration of the nuclei. If there is only one type of atom present, which has a spherically symmetric potential, all the uk (ω, ·) are the same, and Vω is periodic. Now assume that there are two kinds a and b of atoms present, which have spherically symmetric atomic potentials of the same shape, but which differ in their nuclear charge numbers. In this case the potential looks like Vω (x) :=
数学专业英语(修订版2)
slice fundamental
k• ±Ï ëþz Ïf C ©) og 4• Ö ©ª Ø Œ
a —8 ½n p
d òÿ ¦ > 5‰z ˜¡ Ä
notation identity sphere lemma
Rd
and it is well defined for a.e. x.
obviously f (x−y)g(y)dy = f (x)g(x−y)dy and if f and g are measurable(integrable), then f ∗ g is also measurable(integrable), and ||f ∗ g|| ≤ ||f || · ||g||.
dust sequence characteristic compact completion hypothesis convex counting rectifiable difference mapping rational preserving
metric series jump positive smooth gradient
as x → ∞. (1) There exists a positive continuous function f on R so that f is integrable
∞ j=1
m(Ej
).
6.Countable intersections of open sets which are called Gδ sets, consider their com-
plements, the countable union of closed sets called the Fδ sets. A subset E of Rd is measurable: (1)if and only if E differs from a Gδ by a set of
高等数学英语词汇
高等数学英语词汇高等数学英语词汇引导语:高等数学指相对于初等数学而言,数学的对象及方法较为繁杂的'一部分。
以下是店铺分享给大家的高等数学英语词汇,欢迎阅读!Aabelian group:阿贝尔群; absolute geometry:绝对几何; absolute value:绝对值; abstract algebra:抽象代数; addition:加法; algebra:代数; algebraicclosure:代数闭包; algebraic geometry:代数几何;algebraic geometry and analytic geometry:代数几何和解析几何; algebraic numbers:代数数; algorithm:算法; almost all:绝大多数; analytic function:解析函数; analytic geometry:解析几何; and:且;angle:角度; anticommutative:反交换律; antisymmetric relation:反对称关系; antisymmetry:反对称性; approximately equal:约等于; Archimedean field:阿基米德域; Archimedean group:阿基米德群; area:面积; arithmetic:算术; associative algebra:结合代数; associativity:结合律; axiom:公理; axiom of constructibility:可构造公理; axiom of empty set:空集公理;axiom of extensionality:外延公理; axiom of foundation:正则公理; axiom of pairing:对集公理; axiom of regularity:正则公理; axiom of replacement:代换公理; axiom of union:并集公理; axiom schema of separation:分离公理; axiom schema of specification:分离公理;axiomatic set theory:公理集合论; axiomatic system:公理系统;BBaire space:贝利空间; basis:基; Bézout's identity:贝祖恒等式; Bernoulli's inequality:伯努利不等式 ; Big O notation:大O符号; bilinear operator:双线性算子; binary operation:二元运算; binary predicate:二元谓词; binary relation:二元关系; Booleanalgebra:布尔代数;Boolean logic:布尔逻辑; Boolean ring:布尔环; boundary:边界; boundary point:边界点;bounded lattice:有界格;Ccalculus:微积分学; Cantor's diagonal argument:康托尔对角线方法; cardinal number:基数;cardinality:势; cardinality of the continuum:连续统的势; Cartesian coordinate system:直角坐标系; Cartesian product:笛卡尔积; category:范畴; Cauchy sequence:柯西序列; Cauchy-Schwarz inequality:柯西不等式; Ceva's Theorem:塞瓦定理; characteristic:特征;characteristic polynomial:特征多项式; circle:圆; class:类; closed:闭集; closure:封闭性或闭包; closure algebra:闭包代数; combinatorial identities:组合恒等式; commutativegroup:交换群; commutative ring:交换环; commutativity::交换律; compact:紧致的;compact set:紧致集合; compact space:紧致空间; complement:补集或补运算; completelattice:完备格; complete metric space:完备的度量空间; complete space:完备空间; complexmanifold:复流形; complex plane:复平面; congruence:同余; congruent:全等; connectedspace:连通空间; constructible universe:可构造全集; constructions of the real numbers:实数的构造; continued fraction:连分数; continuous:连续; continuum hypothesis:连续统假设;contractible space:可缩空间; convergence space:收敛空间; cosine:余弦; countable:可数;countable set:可数集; cross product:叉积; cycle space:圈空间; cyclic group:循环群;Dde Morgan's laws:德·摩根律; Dedekind completion:戴德金完备性; Dedekind cut:戴德金分割;del:微分算子; dense:稠密; densely ordered:稠密排列; derivative:导数; determinant:行列式; diffeomorphism:可微同构; difference:差; differentiablemanifold:可微流形;differential calculus:微分学; dimension:维数; directed graph:有向图; discrete space:离散空间; discriminant:判别式; distance:距离; distributivity:分配律; dividend:被除数;dividing:除; divisibility:整除; division:除法; divisor:除数; dot product:点积;Eeigenvalue:特征值; eigenvector:特征向量; element:元素; elementary algebra:初等代数;empty function:空函数; empty set:空集; empty product:空积; equal:等于; equality:等式或等于; equation:方程; equivalence relation:等价关系; Euclidean geometry:欧几里德几何;Euclidean metric:欧几里德度量; Euclidean space:欧几里德空间; Euler's identity:欧拉恒等式;even number:偶数; event:事件; existential quantifier:存在量词; exponential function:指数函数; exponential identities:指数恒等式; expression:表达式; extended real number line:扩展的实数轴;Ffalse:假; field:域; finite:有限; finite field:有限域; finite set:有限集合; first-countablespace:第一可数空间; first order logic:一阶逻辑; foundations of mathematics:数学基础;function:函数; functional analysis:泛函分析; functional predicate:函数谓词;fundamental theorem of algebra:代数基本定理; fraction:分数;Ggauge space:规格空间; general linear group:一般线性群; geometry:几何学; gradient:梯度;graph:图; graph of a relation:关系图; graph theory:图论; greatest element:最大元;group:群; group homomorphism:群同态;HHausdorff space:豪斯多夫空间; hereditarily finite set:遗传有限集合; Heron's formula:海伦公式; Hilbert space:希尔伯特空间;Hilbert's axioms:希尔伯特公理系统; Hodge decomposition:霍奇分解; Hodge Laplacian:霍奇拉普拉斯算子; homeomorphism:同胚; horizontal:水平;hyperbolic function identities:双曲线函数恒等式; hypergeometric function identities:超几何函数恒等式; hyperreal number:超实数;Iidentical:同一的; identity:恒等式; identity element:单位元; identity matrix:单位矩阵;idempotent:幂等; if:若; if and only if:当且仅当; iff:当且仅当; imaginary number:虚数;inclusion:包含; index set:索引集合; indiscrete space:非离散空间; inequality:不等式或不等; inequality of arithmetic and geometric means:平均数不等式; infimum:下确界; infiniteseries:无穷级数; infinite:无穷大; infinitesimal:无穷小; infinity:无穷大; initial object:初始对象; inner angle:内角; inner product:内积; inner product space:内积空间; integer:整数; integer sequence:整数列; integral:积分; integral domain:整数环; interior:内部;interior algebra:内部代数; interior point:内点; intersection:交集; inverse element:逆元;invertible matrix:可逆矩阵; interval:区间; involution:回旋; irrational number:无理数;isolated point:孤点; isomorphism:同构;JJacobi identity:雅可比恒等式; join:并运算;K格式: Kuratowski closure axioms:Kuratowski 闭包公理;Lleast element:最小元; Lebesgue measure:勒贝格测度; Leibniz's law:莱布尼茨律; Liealgebra:李代数; Lie group:李群; limit:极限; limit point:极限点; line:线; line segment:线段; linear:线性; linear algebra:线性代数; linear operator:线性算子; linear space:线性空间; linear transformation:线性变换; linearity:线性性; list of inequalities:不等式列表; list oflinear algebra topics:线性代数相关条目; locally compact space:局部紧致空间; logarithmicidentities:对数恒等式; logic:逻辑学; logical positivism:逻辑实证主义; law of cosines:余弦定理; L??wenheim-Skolem theorem:L??wenheim-Skolem 定理; lower limit topology:下限拓扑;Mmagnitude:量; manifold:流形; map:映射; mathematical symbols:数学符号; mathematicalanalysis:数学分析; mathematical proof:数学证明; mathematics:数学; matrix:矩阵;matrix multiplication:矩阵乘法; meaning:语义; measure:测度; meet:交运算; member:元素; metamathematics:元数学; metric:度量; metric space:度量空间; model:模型; modeltheory:模型论; modular arithmetic:模运算; module:模; monotonic function:单调函数;multilinear algebra:多重线性代数; multiplication:乘法; multiset:多样集;Nnaive set theory:朴素集合论; natural logarithm:自然对数; natural number:自然数; naturalscience:自然科学; negative number:负数; neighbourhood:邻域; New Foundations:新基础理论; nine point circle:九点圆; non-Euclidean geometry:非欧几里德几何; nonlinearity:非线性; non-singular matrix:非奇异矩阵; nonstandard model:非标准模型; nonstandardanalysis:非标准分析; norm:范数; normed vector space:赋范向量空间; n-tuple:n 元组或多元组; nullary:空; nullary intersection:空交集; number:数; number line:数轴;Oobject:对象; octonion:八元数; one-to-one correspondence:一一对应; open:开集; openball:开球; operation:运算; operator:算子; or:或; order topology:序拓扑; ordered field:有序域;ordered pair:有序对; ordered set:偏序集; ordinal number:序数; ordinarymathematics:一般数学; origin:原点; orthogonal matrix:正交矩阵;Pp-adic number:p进数; paracompact space:仿紧致空间; parallel postulate:平行公理;parallelepiped:平行六面体; parallelogram:平行四边形; partial order:偏序关系; partition:分割; Peano arithmetic:皮亚诺公理; Pedoe's inequality:佩多不等式; perpendicular:垂直;philosopher:哲学家; philosophy:哲学; philosophy journals:哲学类杂志; plane:平面; pluralquantification:复数量化; point:点; Point-Line-Plane postulate:点线面假设; polarcoordinates:极坐标系; polynomial:多项式; polynomial sequence:多项式列; positive-definitematrix:正定矩阵; positive-semidefinite matrix:半正定矩阵; power set:幂集; predicate:谓词; predicate logic:谓词逻辑; preorder:预序关系; prime number:素数; product:积;proof:证明; proper class:纯类; proper subset:真子集; property:性质; proposition:命题; pseudovector:伪向量; Pythagorean theorem:勾股定理;QQ.E.D.:Q.E.D.; quaternion:四元数; quaternions and spatial rotation:四元数与空间旋转;question:疑问句; quotient field:商域; quotient set:商集;Rradius:半径; ratio:比; rational number:有理数; real analysis:实分析; real closed field:实闭域; real line:实数轴; real number:实数; real number line:实数线; reflexive relation:自反关系; reflexivity:自反性; reification:具体化; relation:关系; relative complement:相对补集;relatively complemented lattice:相对补格; right angle:直角; right-handed rule:右手定则;ring:环;Sscalar:标量; second-countable space:第二可数空间; self-adjoint operator:自伴随算子;sentence:判断; separable space:可分空间; sequence:数列或序列; sequence space:序列空间; series:级数; sesquilinear function:半双线性函数; set:集合; set-theoretic definitionof natural numbers:自然数的集合论定义; set theory:集合论; several complex variables:一些复变量; shape:几何形状; sign function:符号函数; singleton:单元素集合; social science:社会科学; solid geometry:立体几何; space:空间; spherical coordinates:球坐标系; squarematrix:方块矩阵; square root:平方根; strict:严格; structural recursion:结构递归;subset:子集; subsequence:子序列; subspace:子空间; subspace topology:子空间拓扑;subtraction:减法; sum:和; summation:求和; supremum:上确界; surreal number:超实数; symmetric difference:对称差; symmetric relation:对称关系; system of linearequations:线性方程组;Ttensor:张量; terminal object:终结对象; the algebra of sets:集合代数; theorem:定理; topelement:最大元; topological field:拓扑域; topological manifold:拓扑流形; topological space:拓扑空间; topology:拓扑或拓扑学; total order:全序关系; totally disconnected:完全不连贯;totally ordered set:全序集; transcendental number:超越数; transfinite recursion:超限归纳法; transitivity:传递性; transitive relation:传递关系; transpose:转置; triangleinequality:三角不等式; trigonometric identities:三角恒等式; triple product:三重积; trivialtopology:密着拓扑; true:真; truth value:真值;Uunary operation:一元运算; uncountable:不可数; uniform space:一致空间; union:并集;unique:唯一; unit interval:单位区间; unit step function:单位阶跃函数; unit vector:单位向量;universal quantification:全称量词; universal set:全集; upper bound:上界;Vvacuously true:??; Vandermonde's identity:Vandermonde 恒等式; variable:变量;vector:向量; vector calculus:向量分析; vector space:向量空间; Venn diagram:文氏图;volume:体积; von Neumann ordinal:冯·诺伊曼序数; von Neumann universe:冯·诺伊曼全集;vulgar fraction:分数;ZZermelo set theory:策梅罗集合论; Zermelo-Fraenkel set theory:策梅罗-弗兰克尔集合论; ZF settheory:ZF 系统; zero:零; zero object:零对象;下载全文。
The operator-product expansion away from euclidean region
arX iv :h e p -p h /9811293v 1 10 N o v 1998The operator-product expansion away from euclidean regionJan Fischer∗Supportedin part by GAAV and GACR (Czech Re-public)under grant numbers A1010711and 202/96/1616respectively.In spite of serious mathematical uncertainties,the operator product expansion is of paramount importance for solving a number of practical problems in quantum chromodynamics.To cal-culate many measurable quantities in QCD,it is necessary to investigate the properties of the OPE in the complex Q 2plane away from the euclidean region,i.e.,away from the semiaxis Q 2>0.This leads us,with regard to (1),to the problem of finding conditions under which a power expan-sion of the typef (1/Q 2)≈ka k (q )/Q 2k (2)can be extended to angles away from the eu-clidean semiaxis in the Q 2plane.But such an extension is a delicate problem requiring precise mathematical conditions,which are not known here.In practical applications,it is usually assumed that the properties of the operator product ex-pansion away from the ray Q 2>0are the same as those along it,except for the cut Q 2<0(the Minkowski region).Instead of making this sim-plifying technical assumption,we prefer to intro-duce some model assumptions which would free the scheme from a priori neglecting the influence of the cut on the truncation error along a ray,keep the model possibly close to real situations and,simultaneously,give the problem precise mathe-matical meaning.2.The modelI will discuss the problem on the example of the following model situation.Let F(s)be holomor-phic in the complex s plane cut along the pos-itive semiaxis,with the possible exception of a bounded domain around the origin.Let the num-bers a k,k=0,1,2,...n−1,and a positive number A n exist such that the inequality|F(s)−n−1k=0a k/(−s)k|<A n/|s|n(3)holds for all real s smaller than a negative num-ber.The problem is under what conditions this inequality can be continued to the complex plane, and what will be its form away from the original region of validity,i.e.away from the negative real semiaxis(euclidean region).This problem is of interest for QCD because it could,when solved,tell us how the inequality (3)develops when the ray along which the opera-tor product expansion is studied departs from the euclidean region towards the Minkowski one.We shall discuss the problem under two simplifying assumptions.Notefirst that the inequality(3)amounts to as-suming that the n-th order remainder R n(−1/s),R n(z)=f(z)−n−1k=0a k z k,(4)tends to zero for z→0as the n-th power of z for at least one value of n.(Here,we use the notation z≡e iϕ=−1/s and f(z)≡F(s).)This assump-tion may appear as too optimistic;indeed,it is difficult to make a realiable estimate of the trun-cation error even in the euclidean region,because it is not known whether there is a limit of QCD in which the operator-product expansion becomes exact.A second assumption we make is that the log-arithmic energy dependence of the expansion co-efficients a k can be neglected.We do not demand,on the other hand,that the series on the left-hand side of(3)be convergent or asymptotic to F(s):our approach is more general and can be applied whenever the remainder obeys (3)at least for one value of n.Assuming the bound(3),we observe how it varies with the deflection of the ray away from euclidean region.It is natural to expect that the solution to the problem depends on additional as-sumptions imposed on the function F(s)≡f(z). In particular,the form of the dependence of the resulting bound is determined by the assumed character of the discontinuity along the cut.We consider two possible sets of such additional assumptions.3.Results(i)In thefirst of them,we assume that f(z) admits the integral representation of the form f(z)= ∞0ρ(t)not consider here.To get closer to physics,we consider an alternative scheme below.(ii)In this second scheme we assume,instead of the above conditions,that f(z)is bounded by a constant M inside a circle of radius d in the cut z plane.The resulting bound on the remainder has the following form:|R n(r e iϕ)|≤M n(r/d n)n(1−|ϕ|/π).(9) Here,M n and d n are constants which related to M and d.This inequality is a special consequence of a general theorem,which will be published sep-arately[3].The inequality(9)gives an upper bound on the remainder R n(z)along every ray tending to the origin(i.e.,to infinite energy),the estimate becoming worse with increasing deflec-tion from the positive real semiaxis(euclidean re-gion),i.e.,with the ray approaching closer the cut.Since the estimate(9)might seem rather loose (note that n in the exponent on the right hand side is multiplied by an angle-dependent factor that vanishes on the cut),it is perhaps worth mentioning that there are functions that saturate it.Details will be discussed in[3].4.DiscussionThe bounds obtained are related to the prob-lem offinding error estimates for the QCD calcu-lations,in which contour integrals of the type 6πi |s|=m2(1−s/m2)k(1+2s/m2τ)l P(s)d sAcknowledgementsHelpful discussions on the subject with M. Beneke,I.Caprini, E.de Rafael,S.Narison, M.Neubert and J.Stern are gratefully acknowl-edged.I am indebted to A.de R´u jula for hospi-tality at the CERN TH Division,and to Stephan Narison for inviting me to this inspiring confer-ence.REFERENCES1.K.G.Wilson,Phys.Rev.179(1969)14992.M.A.Shifman,in Continuous Advances inQCD1994,A.Smilga(ed.),p.249(World Scientific,Singapore,1994)[hep-ph/9405246]3.J.Fischer and I.Vrkoˇc,to be published4.M.Shifman,Int.J.Mod.Phys.A11(1996)31955. E.Braaten,S.Narison and A.Pich,Nucl.Phys.B373(1992)581A.Pich:QCD tests from tau decays.In-vited talk at the20th Johns Hopkins Work-shop(Heidelberg,27-29June1996),hep-ph/9701305F.LeDiberder and A.Pich,Phys.Lett.B289(1992)165。
SCI写作句型汇总
S C I论文写作中一些常用的句型总结(一)很多文献已经讨论过了一、在Introduction里面经常会使用到的一个句子:很多文献已经讨论过了。
它的可能的说法有很多很多,这里列举几种我很久以前搜集的:A.??Solar energy conversion by photoelectrochemical cells?has been intensively investigated.?(Nature 1991, 353, 737 - 740?)B.?This was demonstrated in a number of studies that?showed that composite plasmonic-metal/semiconductor photocatalysts achieved significantly higher rates in various photocatalytic reactions compared with their pure semiconductor counterparts.C.?Several excellent reviews describing?these applications are available, and we do not discuss these topicsD.?Much work so far has focused on?wide band gap semiconductors for water splitting for the sake of chemical stability.(DOI:10.1038/NMAT3151)E.?Recent developments of?Lewis acids and water-soluble organometalliccatalysts?have attracted much attention.(Chem. Rev. 2002, 102, 3641?3666)F.?An interesting approach?in the use of zeolite as a water-tolerant solid acid?was described by?Ogawa et al(Chem.Rev. 2002, 102, 3641?3666)G.?Considerable research efforts have been devoted to?the direct transition metal-catalyzed conversion of aryl halides toaryl nitriles. (J. Org. Chem. 2000, 65, 7984-7989) H.?There are many excellent reviews in the literature dealing with the basic concepts of?the photocatalytic processand the reader is referred in particular to those by Hoffmann and coworkers,Mills and coworkers, and Kamat.(Metal oxide catalysis,19,P755)I. Nishimiya and Tsutsumi?have reported on(proposed)the influence of the Si/Al ratio of various zeolites on the acid strength, which were estimated by calorimetry using ammonia. (Chem.Rev. 2002, 102, 3641?3666)二、在results and discussion中经常会用到的:如图所示A. GIXRD patterns in?Figure 1A show?the bulk structural information on as-deposited films.?B.?As shown in Figure 7B,?the steady-state current density decreases after cycling between 0.35 and 0.7 V, which is probably due to the dissolution of FeOx.?C.?As can be seen from?parts a and b of Figure 7, the reaction cycles start with the thermodynamically most favorable VOx structures(J. Phys. Chem. C 2014, 118, 24950?24958)这与XX能够相互印证:A.?This is supported by?the appearance in the Ni-doped compounds of an ultraviolet–visible absorption band at 420–520nm (see Fig. 3 inset), corresponding to an energy range of about 2.9 to 2.3 eV.B. ?This?is consistent with the observation from?SEM–EDS. (Z.Zou et al. / Chemical Physics Letters 332 (2000) 271–277)C.?This indicates a good agreement between?the observed and calculated intensities in monoclinic with space groupP2/c when the O atoms are included in the model.D. The results?are in good consistent with?the observed photocatalytic activity...E. Identical conclusions were obtained in studies?where the SPR intensity and wavelength were modulated by manipulating the composition, shape,or size of plasmonic nanostructures.?F.??It was also found that areas of persistent divergent surfaceflow?coincide?with?regions where convection appears to be consistently suppressed even when SSTs are above 27.5°C.(二)1. 值得注意的是...A.?It must also be mentioned that?the recycling of aqueous organic solvent is less desirable than that of pure organic liquid.B.?Another interesting finding is that?zeolites with 10-membered ring pores showed high selectivities (>99%) to cyclohexanol, whereas those with 12-membered ring pores, such as mordenite, produced large amounts of dicyclohexyl ether. (Chem. Rev. 2002, 102,3641?3666)C.?It should be pointed out that?the nanometer-scale distribution of electrocatalyst centers on the electrode surface is also a predominant factor for high ORR electrocatalytic activity.D.?Notably,?the Ru II and Rh I complexes possessing the same BINAP chirality form antipodal amino acids as the predominant products.?(Angew. Chem. Int. Ed., 2002, 41: 2008–2022)E. Given the multitude of various transformations published,?it is noteworthy that?only very few distinct?activation?methods have been identified.?(Chem. Soc. Rev., 2009,?38, 2178-2189)F.?It is important to highlight that?these two directing effects will lead to different enantiomers of the products even if both the “H-bond-catalyst” and the?catalyst?acting by steric shielding have the same absolute stereochemistry. (Chem. Soc. Rev.,?2009,?38, 2178-2189)G.?It is worthwhile mentioning that?these PPNDs can be very stable for several months without the observations of any floating or precipitated dots, which is attributed to the electrostatic repulsions between the positively charge PPNDs resulting in electrosteric stabilization.(Adv. Mater., 2012, 24: 2037–2041)2.?...仍然是个挑战A.?There is thereby an urgent need but it is still a significant challenge to?rationally design and delicately tail or the electroactive MTMOs for advanced LIBs, ECs, MOBs, and FCs.?(Angew. Chem. Int. Ed.2 014, 53, 1488 – 1504)B.?However, systems that are?sufficiently stable and efficient for practical use?have not yet been realized.C.??It?remains?challenging?to?develop highly active HER catalysts based on materials that are more abundant at lower costs. (J. Am. Chem.Soc.,?2011,?133, ?7296–7299)D.?One of the?great?challenges?in the twenty-first century?is?unquestionably energy storage. (Nature Materials?2005, 4, 366 - 377?)众所周知A.?It is well established (accepted) / It is known to all / It is commonlyknown?that?many characteristics of functional materials, such as composition, crystalline phase, structural and morphological features, and the sur-/interface properties between the electrode and electrolyte, would greatly influence the performance of these unique MTMOs in electrochemical energy storage/conversion applications.(Angew. Chem. Int. Ed.2014,53, 1488 – 1504)B.?It is generally accepted (believed) that?for a-Fe2O3-based sensors the change in resistance is mainly caused by the adsorption and desorption of gases on the surface of the sensor structure. (Adv. Mater. 2005, 17, 582)C.?As we all know,?soybean abounds with carbon,?nitrogen?and oxygen elements owing to the existence of sugar,?proteins?and?lipids. (Chem. Commun., 2012,?48, 9367-9369)D.?There is no denying that?their presence may mediate spin moments to align parallel without acting alone to show d0-FM. (Nanoscale, 2013,?5, 3918-3930)(三)1. 正如下文将提到的...A.?As will be described below(也可以是As we shall see below),?as the Si/Al ratio increases, the surface of the zeolite becomes more hydrophobic and possesses stronger affinity for ethyl acetate and the number of acid sites decreases.(Chem. Rev. 2002, 102, 3641?3666)B. This behavior is to be expected and?will?be?further?discussed?below. (J. Am. Chem. Soc.,?1955,?77, 3701–3707)C.?There are also some small deviations with respect to the flow direction,?whichwe?will?discuss?below.(Science, 2001, 291, 630-633)D.?Below,?we?will?see?what this implies.E.?Complete details of this case?will?be provided at a?later?time.E.?很多论文中,也经常直接用see below来表示,比如:The observation of nanocluster spheres at the ends of the nanowires is suggestive of a VLS growth process (see?below). (Science, 1998, ?279, 208-211)2. 这与XX能够相互印证...A.?This is supported by?the appearance in the Ni-doped compounds of an ultraviolet–visible absorption band at 420–520 nm (see Fig. 3 inset), corresponding to an energy range of about 2.9 to 2.3 eVB.This is consistent with the observation from?SEM–EDS. (Chem. Phys. Lett. 2000, 332, 271–277)C.?Identical conclusions were obtained?in studies where the SPR intensity and wavelength were modulated by manipulating the composition, shape, or size of plasmonic nanostructures.?(Nat. Mater. 2011, DOI: 10.1038/NMAT3151)D. In addition, the shape of the titration curve versus the PPi/1 ratio,?coinciding withthat?obtained by fluorescent titration studies, suggested that both 2:1 and 1:1 host-to-guest complexes are formed. (J. Am. Chem. Soc. 1999, 121, 9463-9464)E.?This unusual luminescence behavior is?in accord with?a recent theoretical prediction; MoS2, an indirect bandgap material in its bulk form, becomes a direct bandgapsemiconductor when thinned to a monolayer.?(Nano Lett.,?2010,?10, 1271–1275)3.?我们的研究可能在哪些方面得到应用A.?Our ?ndings suggest that?the use of solar energy for photocatalytic watersplitting?might provide a viable source for?‘clean’ hydrogen fuel, once the catalyticef?ciency of the semiconductor system has been improved by increasing its surface area and suitable modi?cations of the surface sites.B. Along with this green and cost-effective protocol of synthesis,?we expect that?these novel carbon nanodots?have potential applications in?bioimaging andelectrocatalysis.(Chem. Commun., 2012,?48, 9367-9369)C.?This system could potentially be applied as?the gain medium of solid-state organic-based lasers or as a component of high value photovoltaic (PV) materials, where destructive high energy UV radiation would be converted to useful low energy NIR radiation. (Chem. Soc. Rev., 2013,?42, 29-43)D.?Since the use of?graphene?may enhance the photocatalytic properties of TiO2?under UV and visible-light irradiation,?graphene–TiO2?composites?may potentially be usedto?enhance the bactericidal activity.?(Chem. Soc. Rev., 2012,?41, 782-796)E.??It is the first report that CQDs are both amino-functionalized and highly fluorescent,?which suggests their promising applications in?chemical sensing.(Carbon, 2012,?50,?2810–2815)(四)1. 什么东西还尚未发现/系统研究A. However,systems that are sufficiently stable and efficient for practical use?have not yet been realized.B. Nevertheless,for conventional nanostructured MTMOs as mentioned above,?some problematic disadvantages cannot be overlooked.(Angew. Chem. Int. Ed.2014,53, 1488 – 1504)C.?There are relatively few studies devoted to?determination of cmc values for block copolymer micelles. (Macromolecules 1991, 24, 1033-1040)D. This might be the reason why, despite of the great influence of the preparation on the catalytic activity of gold catalysts,?no systematic study concerning?the synthesis conditions?has been published yet.?(Applied Catalysis A: General2002, 226, ?1–13)E.?These possibilities remain to be?explored.F.??Further effort is required to?understand and better control the parameters dominating the particle surface passivation and resulting properties for carbon dots of brighter photoluminescence. (J. Am. Chem. Soc.,?2006,?128?, 7756–7757)2.?由于/因为...A.?Liquid ammonia?is particularly attractive as?an alternative to water?due to?its stability in the presence of strong reducing agents such as alkali metals that are used to access lower oxidation states.B.?The unique nature of?the cyanide ligand?results from?its ability to act both as a σdonor and a π acceptor combined with its negativecharge and ambidentate nature.C.?Qdots are also excellent probes for two-photon confocalmicroscopy?because?they are characterized by a very large absorption cross section?(Science ?2005,?307, 538-544).D.?As a result of?the reductive strategy we used and of the strong bonding between the surface and the aryl groups, low residual currents (similar to those observed at a bare electrode) were obtained over a large window of potentials, the same as for the unmodified parent GC electrode. (J. Am. Chem. Soc. 1992, 114, 5883-5884)E.?The small Tafel slope of the defect-rich MoS2 ultrathin nanosheets is advantageous for practical?applications,?since?it will lead to a faster increment of HER rate with increasing overpotential.(Adv. Mater., 2013, 25: 5807–5813)F. Fluorescent carbon-based materials have drawn increasing attention in recent years?owing to?exceptional advantages such as high optical absorptivity, chemical stability, biocompatibility, and low toxicity.(Angew. Chem. Int. Ed., 2013, 52: 3953–3957)G.??On the basis of?measurements of the heat of immersion of water on zeolites, Tsutsumi etal. claimed that the surface consists of siloxane bondings and is hydrophobicin the region of low Al content. (Chem. Rev. 2002, 102, 3641?3666)H.?Nanoparticle spatial distributions might have a large significance for catalyst stability,?given that?metal particle growth is a relevant deactivation mechanism for commercial catalysts.?3. ...很重要A.?The inhibition of additional nucleation during growth, in other words, the complete separation?of nucleation and growth,?is?critical(essential, important)?for?the successful synthesis of monodisperse nanocrystals. (Nature Materials?3, 891 - 895 (2004))B.??In the current study,?Cys,?homocysteine?(Hcy) and?glutathione?(GSH) were chosen as model?thiol?compounds since they?play important (significant, vital, critical) roles?in many biological processes and monitoring of these?thiol?compounds?is of great importance for?diagnosis of diseases.(Chem. Commun., 2012,?48, 1147-1149)C.?This is because according to nucleation theory,?what really matters?in addition to the change in temperature ΔT?(or supersaturation) is the cooling rate.(Chem. Soc. Rev., 2014,?43, 2013-2026)(五)1. 相反/不同于A.?On the contrary,?mononuclear complexes, called single-ion magnets (SIM), have shown hysteresis loops of butterfly/phonon bottleneck type, with negligiblecoercivity, and therefore with much shorter relaxation times of magnetization. (Angew. Chem. Int. Ed., 2014, 53: 4413–4417)B.?In contrast,?the Dy compound has significantly larger value of the transversal magnetic moment already in the ground state (ca. 10?1?μB), therefore allowing a fast QTM. (Angew. Chem. Int. Ed., 2014, 53: 4413–4417)C.?In contrast to?the structural similarity of these complexes, their magnetic behavior exhibits strong divergence.?(Angew. Chem. Int. Ed., 2014, 53: 4413–4417)D.?Contrary to?other conducting polymer semiconductors, carbon nitride ischemically and thermally stable and does not rely on complicated device manufacturing. (Nature materials, 2009, 8(1): 76-80.)E.?Unlike?the spherical particles they are derived from that Rayleigh light-scatter in the blue, these nanoprisms exhibit scattering in the red, which could be useful in developing multicolor diagnostic labels on the basis not only of nanoparticle composition and size but also of shape. (Science 2001,? 294, 1901-1903)2. 发现,阐明,报道,证实可供选择的词包括:verify, confirm, elucidate, identify, define, characterize, clarify, establish, ascertain, explain, observe, illuminate, illustrate,demonstrate, show, indicate, exhibit, presented, reveal, display, manifest,suggest, propose, estimate, prove, imply, disclose,report, describe,facilitate the identification of?举例:A. These stacks appear as nanorods in the two-dimensional TEM images, but tilting experiments?confirm that they are nanoprisms.?(Science 2001,? 294, 1901-1903)B. Note that TEM?shows?that about 20% of the nanoprisms are truncated.?(Science 2001,? 294, 1901-1903)C. Therefore, these calculations not only allow us to?identify?the important features in the spectrum of the nanoprisms but also the subtle relation between particle shape and the frequency of the bands that make up their spectra.?(Science 2001,? 294, 1901-1903)D. We?observed?a decrease in intensity of the characteristic surface plasmon band in the ultraviolet-visible (UV-Vis) spectroscopy for the spherical particles at λmax?= 400 nm with a concomitant growth of three new bands of λmax?= 335 (weak), 470 (medium), and 670 nm (strong), respectively. (Science 2001,? 294, 1901-1903)E. In this article, we present data?demonstrating?that opiate and nonopiate analgesia systems can be selectively activated by different environmental manipulationsand?describe?the neural circuitry involved. (Science 1982, 216, 1185-1192)F. This?suggests?that the cobalt in CoP has a partial positive charge (δ+), while the phosphorus has a partial negative charge (δ?),?implying?a transfer of electron density from Co to P.?(Angew. Chem., 2014, 126: 6828–6832)3. 如何指出当前研究的不足A. Although these inorganic substructures can exhibit a high density of functional groups, such as bridging OH groups, and the substructures contribute significantly to the adsorption properties of the material,surprisingly little attention has been devoted to?the post-synthetic functionalization of the inorganic units within MOFs. (Chem. Eur. J., 2013, 19: 5533–5536.)B.?Little is known,?however, about the microstructure of this material. (Nature Materials 2013,12, 554–561)C.?So far, very little information is available, and only in?the absorber film, not in the whole operational devices. (Nano Lett.,?2014,?14?(2), pp 888–893)D.?In fact it should be noted that very little optimisation work has been carried out on?these devices. (Chem. Commun., 2013,?49, 7893-7895)E. By far the most architectures have been prepared using a solution processed perovskite material,?yet a few examples have been reported that?have used an evaporated perovskite layer. (Adv. Mater., 2014, 27: 1837–1841.)F. Water balance issues have been effectively addressed in PEMFC technology through a large body of work encompassing imaging, detailed water content and water balance measurements, materials optimization and modeling,?but very few of these activities have been undertaken for?anion exchange membrane fuel cells,? primarily due to limited materials availability and device lifetime. (J. Polym. Sci. Part B: Polym. Phys., 2013, 51: 1727–1735)G. However,?none of these studies?tested for Th17 memory, a recently identified T cell that specializes in controlling extracellular bacterial infections at mucosal surfaces. (PNAS, 2013,?111, 787–792)H. However,?uncertainty still remains as to?the mechanism by which Li salt addition results in an extension of the cathodic reduction limit. (Energy Environ. Sci., 2014,?7, 232-250)I.?There have been a number of high profile cases where failure to?identify the most stable crystal form of a drug has led to severe formulation problems in manufacture. (Chem. Soc. Rev., 2014,?43, 2080-2088)J. However,?these measurements systematically underestimate?the amount of ordered material. ( Nature Materials 2013, 12, 1038–1044)(六)1.?取决于a.?This is an important distinction, as the overall activity of a catalyst will?depend on?the material properties, synthesis method, and other possible species that can be formed during activation.?(Nat. Mater.?2017,16,225–229)b.?This quantitative partitioning?was determined by?growing crystals of the 1:1 host–guest complex between?ExBox4+?and corannulene. (Nat. Chem.?2014,?6177–178)c.?They suggested that the Au particle size may?be the decisive factor for?achieving highly active Au catalysts.(Acc. Chem. Res.,?2014,?47, 740–749)d.?Low-valent late transition-metal catalysis has?become indispensable to?chemical synthesis, but homogeneous high-valent transition-metal catalysis is underdeveloped, mainly owing to the reactivity of high-valent transition-metal complexes and the challenges associated with synthesizing them.?(Nature2015,?517,449–454)e.?The polar effect?is a remarkable property that enables?considerably endergonic C–H abstractions?that would not be possible otherwise.?(Nature?2015, 525, 87–90)f.?Advances in heterogeneous catalysis?must rely on?the rational design of new catalysts. (Nat. Nanotechnol.?2017, 12, 100–101)g.?Likely, the origin of the chemoselectivity may?be also closely related to?the H?bonding with the N or O?atom of the nitroso moiety, a similar H-bonding effect is known in enamine-based nitroso chemistry. (Angew. Chem. Int. Ed.?2014, 53: 4149–4153)2.?有很大潜力a.?The quest for new methodologies to assemble complex organic molecules?continues to be a great impetus to?research efforts to discover or to optimize new catalytic transformations. (Nat. Chem.?2015,?7, 477–482)b.?Nanosized faujasite (FAU) crystals?have great potential as?catalysts or adsorbents to more efficiently process present and forthcoming synthetic and renewablefeedstocks in oil refining, petrochemistry and fine chemistry. (Nat. Mater.?2015, 14, 447–451)c.?For this purpose, vibrational spectroscopy?has proved promising?and very useful.?(Acc Chem Res. 2015, 48, 407–413.)d.?While a detailed mechanism remains to be elucidated and?there is room for improvement?in the yields and selectivities, it should be remarked that chirality transfer upon trifluoromethylation of enantioenriched allylsilanes was shown. (Top Catal.?2014,?57: 967.?)e.?The future looks bright for?the use of PGMs as catalysts, both on laboratory and industrial scales, because the preparation of most kinds of single-atom metal catalyst is likely to be straightforward, and because characterization of such catalysts has become easier with the advent of techniques that readily discriminate single atoms from small clusters and nanoparticles. (Nature?2015, 525, 325–326)f.?The unique mesostructure of the 3D-dendritic MSNSs with mesopore channels of short length and large diameter?is supposed to be the key role in?immobilization of active and robust heterogeneous catalysts, and?it would have more hopeful prospects in?catalytic applications. (ACS Appl. Mater. Interfaces,?2015,?7, 17450–17459)g.?Visible-light photoredox catalysis?offers exciting opportunities to?achieve challenging carbon–carbon bond formations under mild and ecologically benign conditions. (Acc. Chem. Res.,?2016, 49, 1990–1996)3. 因此同义词:Therefore, thus, consequently, hence, accordingly, so, as a result这一条比较简单,这里主要讲一下这些词的副词词性和灵活运用。
Coincidence of the continuous and discrete p-adic wavelet transforms
2
Continuous p–adic wavelet transform
For the notations used in the present section see the Appendix. Let us consider the main construction of the present paper — the continuous p–adic wavelet transform generated by the p–adic wavelet of the form ψ (x) = χ(p−1 x)Ω(|x|p ) which is equal to the product of a character χ and the characteristic function Ω of a ball. In the next lemma we show that any vector from the basis {ψγnj } of p–adic wavelets is a translation and dilation of the wavelet ψ , and, vice versa, any translation and dilation of the wavelet ψ belongs to the basis {ψγnj } up to multiplication by some root of one. Equivalently, the basis of p–adic wavelets (multiplied by corresponding roots of one) can be considered as an orbit of action of the p–adic affine group in L2 (Qp ) containing the function ψ . 2
Two-dimensional Quantum Field Theory, examples and applications
Abstract The main principles of two-dimensional quantum field theories, in particular two-dimensional QCD and gravity are reviewed. We study non-perturbative aspects of these theories which make them particularly valuable for testing ideas of four-dimensional quantum field theory. The dynamics of confinement and theta vacuum are explained by using the non-perturbative methods developed in two dimensions. We describe in detail how the effective action of string theory in non-critical dimensions can be represented by Liouville gravity. By comparing the helicity amplitudes in four-dimensional QCD to those of integrable self-dual Yang-Mills theory, we extract a four dimensional version of two dimensional integrability.
2 48 49 52 54 56
5 Four-dimensional analogies and consequences 6 Conclusions and Final Remarks
Lecture notes
Introduction to symplectic topologyLecture notes1.Linear symplectic geometry.1.1.Let V be a vector space andωa non-degenerate skew-symmetric bilinear form on V.Suchωis called a linear symplectic structure.We writeω(u,v)for u,v∈V.The only difference with(pseudo)Euclidean structure is that the latter is symmetric.Fix a dot product in V.Then one can write:ω(u,v)=Ju·vwhere J is non-degenerate operator on V.Sinceωis skew-symmetric,J∗=−J.Taking determinants,det J∗=det J=(−1)n det Jwhere n=dim V.Thus n is even.Examples. 1.The plane with an area form(i.e.,cross-product)is a symplectic space.All2-dimensional symplectic spaces are symplectomorphic to this one.In formulas,ω=dp∧dq(using the language of linear differential forms).2.One can take direct sum of the previous example to obtain symplectic R2n with the symplectic structure dp∧dq=dp1∧dq1+...+dp n∧dq n.One has:ω(q i,q j)=ω(p i,p j)=0 andω(p i,q j)=δij.This is a symplectic basis;the respective coordinates are called Darboux coordinates.3.More conceptually,let W be a vector space.Then V=W⊕W∗is a symplectic space.The structure is as follows:ω((u1,l1),(u2,l2))=l1(u2)−l2(u1).Check that this is non-degenerate.Exercise.Let J be a skew-symmetric matrix:J∗=−J.Then det J is a polynomial in the entries of J,,and this polynomial is the square of another polynomial in the entries of J:det J=(Pf J)2.The latter is called Pfaffian.Show thatPf(A∗JA)=det A Pf J.As in Euclidean geometry,one defines(skew)orthogonal complement of a space.Unlike Euclidean geometry,one may have:U⊂U⊥.For example,this is the case when dim U=1.If U⊂U⊥then U is called isotropic.One has:dim U⊥=2n−dim U where2n is the dimension of the ambient space.Thus if U is isotropic then dim U≤n.An isotropic subspace of dimension n is called Lagrangian.Exercises. 1.Let A:W→W∗be a linear map.Then A∗=A if and only if the graph GrA⊂W⊕W∗is a Lagrangian subspace(with respect to the structure of Example 3above).2.Given two symplectic spaces(V1,ω1)and(V2,ω2)of the same dimensions and a linear map A:V1→V2,the map A is a symplectomorphism if and only if GrA⊂V1⊕V2 is a Lagrangian subspace with respect to the symplectic structureω1 ω2.1.2.Similarly to Euclidean spaces,the dimension is the only linear symplectic invari-ant.Linear Darboux Theorem.Two symplectic spaces of the same dimension are linearly symplectomorphic.Proof.Given a symplectic space V2n,pick a Lagrangian subspace W⊂V.To construct W,choose v1∈V,consider v⊥1,choose v2∈v⊥1,consider v⊥1∩v⊥2,choose v3∈v⊥1∩v⊥2,etc.,until one has v1,...,v n such thatω(v i,v j)=0.These vectors span a Lagrangian space.Claim:V is linearly symplectomorphic to the symplectic space W⊕W∗of Example 3in1.1.To see this,pick another Lagrangian subspace U,transverse to W.Then U is identified with W∗:the pairing between U and W is given byω.Since V=U⊕W,we have the desired symplectomorphism.Thus,one may choose one’s favorite model of a symplectic space.For example,one√may identify R2n with C n,and then J from1.1is the operator of multiplication byExample.Λ1is the space of lines through the origin in the plane,i.e.,RP1,topo-logically,a circle.Exercise∗.What is the topology ofΛ2?Describe a related classical construction realizingΛ2as a quadratic hypersurface of signature(+++−−)in RP4.Let the symplectic space be R4withω=p1∧q1+p2∧q2. Given a2-plane U,choose u1,u2∈U and consider the bivectorφ=u1∧u2.Thus we assignφ∈Λ2U,andφis defined up to a factor.We have constructed a map G2,2→P(Λ2U)=RP5.The bivectors inΛ2U corresponding to2-planes,satisfyφ∧φ=0(and this is sufficient too).Thus G2,2is realized a quadratic hypersurface in RP5of signature (+++−−−).If U is a Lagrangian plane thenφ∧ω=0(why?)and this is also sufficient.This is a linear condition that determines a hyperplane RP4⊂RP5.This hyperplane is transverse to the image of G2,2(why?),and the intersection is the Lagrangian Grassmanian.1.4.Given a symplectic space(V2n,ω),the group of linear symplectomorphisms is called the linear symplectic group and denoted by Sp(V)or Sp(2n,R).A symplectic space has a volume elementω∧n,therefore Sp(2n)is a subgroup of SL(2n).Let A∈Sp(2n).Thenω(Au,Av)=ω(u,v)for all u,v.Thus A∗JA=J.This is interesting to compare with the orthogonal group:A∗A=E.The relations between the classical groups are as follows.Lemma.One has:Sp(2n)∩O(2n)=Sp(2n)∩GL(n,C)=O(2n)∩GL(n,C)=U(n).Proof.One has:A∈GL(n,C)iffAJ=JA;A∈Sp(2n)iffA∗JA=J;andA∈O(2n)iffA∗A=E.Any two of these conditions imply the third.A linear map that preserves the Euclidean and the symplectic structures also preserves the Hermitian one,that is,belongs to U(n).Exercises.1.Let A∈Sp(2n)andλbe an eigenvalue of A.Prove that so are¯λand 1/λ.2.Prove that if A is symplectic then A∗is antisymplectic,that is,ω(A∗u,A∗v)=−ω(u,v)or,equivalently,AJA∗=−J.In fact,U(n)is the maximal compact subgroup of Sp(2n),and the latter is homo-topically equivalent to the former.As a consequence,π1(Sp(2n))=Z.Indeed,one has afibration det:U(n)→S1withfiber SU(n).The latter group is simply connected as follows inductively from the exact homotopy sequence of thefibration SU(n)→S2n−1 withfiber SU(n−1).1.5.Let us describe the Lie algebra sp(2n)of the Lie group Sp(2n).Let A∈Sp(2n) be close to the identity:A=E+tH+O(t2).Then the conditionω(Au,Av)=ω(u,v)for all u,v implies:ω(Hu,v)+ω(u,Hv)=0;in other words,JH+H∗J=0.Thus H is skew-symmetric with respect toω.Such H is called a Hamiltonian operator.The commutator of Hamiltonian operators is again a Hamiltonian operator.To a Hamiltonian operator there corresponds a quadratic form h(u)=ω(u,Hu)/2 called the Hamiltonian(function)of H.One can recover H from h sinceω(u,Hv)= h(u+v)−h(u)−h(v).This gives a one-one correspondence between sp(2n)and quadratic forms on V2n.Thus dim sp(2n)=n(2n+1).In terms of quadratic forms,the commutator writes as follows:{h1,h2}(u)=ω(u,(H2H1−H1H2)u)/2=ω(H1u,H2u).The operation on the LHS is called the Poisson bracket.To write formulas,it is convenient to identify linear operators with linear vectorfields: the operator H is understood as the linear differential equation u =Hu.Let(p,q)be Darboux coordinates.Lemma.The next formulas hold:H=h p∂q−h q∂p;{h1,h2}=(h1)p(h2)q−(h1)q(h2)p.Proof.To prove thefirst formula we need to show that2h=ω((p,q),(−h q,h p)).The RHS is ph p+qh q=2h,due to the Euler formula.Then the Poisson bracket is given by{h1,h2}=ω(((h2)p,−(h2)q),((h1)p,−(h1)q))=(h1)p(h2)q−(h1)q(h2)p,as claimed.More conceptually,given a quadratic form h,one considers its differential dh which is a linear differential1-form.The symplectic structure determines a linear isomorphism V→V∗which makes dh into a linear vectorfield H,that is,i Hω=−dh.1.6.One of thefirst,and most celebrated,results of symplectic topology was Gromov’s nonsqueezing theorem(1985).Let us discuss its linear version(which is infinitely simpler).Given a ball B2n(r)of radius r and a symplectic cylinder C(R)=B2(R)×R2n−2 (where the2-disc is spanned by the Darboux coordinates p1,q1),assume that there is an affine symplectic map F that takes B2n(r)inside C(R).Proposition.Then r≤R.Note that this is false for volume-preserving affine maps.Proof.The map writes F:v→Av+b where A∈Sp(2n)and b∈R2n.Assume r=1.Consider A∗and its two columnsξ1andξ2corresponding to p1,q1Darboux coordinates.Since A∗is antisymplectic(Exercise in1.4),|ω(ξ1,ξ2)|=1,and therefore |ξ1||ξ2|≥1.Assume that|ξ1|≥1,and let v=ξ1/|ξ1|.Note thatξ1andξ2are rows of A (corresponding to coordinates p1,q1).Since F(v)∈C(R),one has:(ξ1·v+b1)2+(ξ2·v+b2)2≤R2,and then|(|ξ1|+b1)|≤R.For b1≥0this implies R≥1,and for b1<0one should replace v by−v.One defines an affine symplectic invariant called linear symplectic width of a subset A⊂R2n:w(A)=max{πr2|F(B2n(r))⊂A for some affine symplectic F}. Symplectic width is monotonic:if A⊂B then w(B)≥w(A),homogeneous of degree2 with respect to dilations and nontrivial:w(B2n(r))=w(C(r))=πr2.To get a better feel of linear symplectic space,classify the ellipsoids.In Euclidean space,every ellipsoid can be written asnx2ii=1,r2iand the radii0≤r1≤...≤r n are uniquely defined.Proof.Recall how to prove the Euclidean fact.We have two Euclidean structures: u·v and Au·v.Here A is self-adjoint,and we assume,it is in general position.Consider a relative extremum problem of Au·u relative u·u.The extremum condition(Lagrange multipliers!)is that Audu=λudu,that is,Au=λu.The function Au·u is an even function on the unit sphere,that is,a function on RP n−1,and it has n critical points. Thus A has n real eigenvalues a1,...,a n,and the respective eigenspaces are orthogonal. We obtain the desired expression.A symplectic analog is as follows.We have a dot product and a symplectic structure ω(u,v)=Ju·v.Consider a relative extremum problem ofω(u,v)relative u·u and v·v. The extremum condition is:Ju dv−Jv du=λu du+µv dv,that is,Ju=µv,Jv=−λu.Thus u,v are eigenvectors of J2(with eigenvalue−λµ),a self-adjoint operator.In general position,these eigenspaces are2-dimensional and pairwise orthogonal.Thus the space is the orthogonal sum of2-dimensional subspaces.Claim:they are also symplectically orthogonal.Indeed,ω(u1,u2)=Ju1·u2=µ1v1·u2=0and,likewise,withω(u1,v2)andω(v1,v2).It remains to choose an orthogonal basis p i,q i in each2-space so that p i·p i=q i·q i andω(p i,q i)=1.The last thing to check is that the radii r i are uniquely defined.Let D(r)be the diagonal matrix with the entries1/r2i.Assume that,for a symplectic matrix A,one has:A∗D(r)A=D(r ).Since A is symplectic,A∗JA=J,or A∗=JA−1J−1.Thus A−1J−1D(r)A=J−1D(r ),that is,the eigenvalues of the matrices J−1D(r)and J−1D(r ) coincide.It follows that r=r .2.Symplectic manifolds.2.1.Let M be a smooth manifold.A symplectic structure on M is a non-degenerate closed2-formω.Since it is non-degenerate,dim M=2n.In other words,dω=0and ω∧...∧ω(n times)is a volume form.In particular,M is oriented.Also,H2(M,R)=0. Hence S2n,n≥2is not symplectic.A symplectomorphism is a diffeomorphism f:M→M such that f∗(ω)=ω.Sym-plectomorphisms form an infinite-dimensional group.2.2.Examples.(a)Linear symplectic space R2n withω=dp∧dq.(b)Any oriented surface with an area form.For example,S2,with the(standard) area formωx(u,v)=det(x,u,v).(c)(Archimedes)Consider the unit sphere and the circumscribed cylinder with its standard area form.Consider the radial projectionπfrom the sphere to the cylinder.Exercise.Prove thatπis a symplectomorphism.(d)The product of symplectic manifolds is a symplectic manifold.(e)Cotangent bundle(important for mechanics!).On T∗M one has a canonical1-formλcalled the Liouville(or action)form.Letπ:T∗M→M be the projection andξbe a tangent vector to T∗M at point(x,p).Define:λ(ξ)=p(π∗(ξ)).In coordinates,λ=pdq where q are local coordinates on M and p are the corresponding covectors(momenta).The canonical symplectic structure on T∗M isω=dλ,locally,dp∧dq.Exercise.Letαbe a1-form on M.Thenαdetermines a sectionγof the cotangent bundle.Prove thatγ∗(λ)=α.(f)CP n.First,consider C n+1=R2n+2with its linear symplectic structureΩ.Con-sider the unit sphere S2n+1.The restriction ofΩon S2n+1has a1-dimensional kernel. Claim:at point x,this kernel is generated by the vector Jx.Indeed,if u⊥x then Ω(Jx,u)=J(Jx)·u=0.The vectorfield Jx generated a foliation on circles,and the space of leaves is CP n.The symplectic structureΩinduces a new symplectic structureωon CP n.The construction is called symplectic reduction.Complex projective varieties are subvarieties of CP n;they have induced symplectic structures,and this is a common source of examples.(g)Another example of symplectic reduction:the space of oriented lines in R n+1. Start with T∗R n+1with its canonical symplectic structureΩ=dp∧dq.Consider the hypersurface|p|=1.Claim:the kernel of the restriction ofΩon this hypersurface at point(p,q)is generated by the vector p∂q.Indeed,(dp∧dq)(u,p∂q)=(pdp)(u)=0.We get a foliation whose leaves are oriented lines(geodesics).We obtain a symplectic structure on the space of oriented linesω=dp∧dq where p is a unit(co)vector and q·p=0.Exercise.Prove that the above space is symplectomorphic to T∗S n.(h)Orbits of the coadjoint representation of a Lie group.Let G be a Lie group and g its Lie algebra.The action of G on itself by conjugation has e as afixed point.Since g=T e G,one obtains a representation Ad of G in g called adjoint.Likewise,one has the coadjoint representation Ad∗in g∗.One also has the respective representations of g denoted by ad and ad∗.In formulas,ad x y=[x,y],(ad∗xξ)(y)=ξ([x,y]),x,y∈g,ξ∈g∗.Theorem(Lie,Kirillov,Kostant,Souriau).An orbit of the coadjoint representation of G has a symplectic structure.Proof.Letξ∈g∗.Then the tangent space to the orbit of the coadjoint representation atξidentifies with g/gξwheregξ={x∈g|ad∗xξ=0}.On the space g/gξone has a skew-symmetric bilinear formω(x,y)=ξ([x,y])(why is it well defined?).This2-form is closed as follows from the Jacobi identity for the Lie algebra g.Exercise.Prove the last statement.Example.Let G=SO(3),then g=so(3),skew-symmetric3×3matrices.Identify them with R3.Given A∈so(3),consider T r(A2).This gives a Euclidean structure on so(3)that agrees with that in R3.We identify g and g∗.Clearly,T r(A2)is invariant under the(co)adjoint action.The orbits are level surfaces of T r(A2),that is,concentric spheres and the origin.Exercise.Similarly study another3-dimensional Lie group,SL(2).2.3.Being non-degenerate,a symplectic form defines an isomorphism between vector fields and1-forms:X→i(X)ω.Afield is called symplectic if i(X)ωis closed,in other words,if L Xω=0;the latter follows from the Cartan formula:L X=di(X)+i(X)d. Symplecticfields form the Lie algebra of the group of symplectomorphisms.Let M be a closed symplectic manifold.Lemma.Given a1-parameter family of vectorfields X t,consider the respective family of diffeomorphismsφt:dφt(x)/dt=X t(φt(x)),φ0=Id.Thenφt are symplectomorphisms for all t iffX t are symplectic for all t.Given symplectic fields X and Y,thefield[X,Y]is symplectic with i([X,Y])ω=dω(X,Y).ω),and this implies thefirst claim.As to the Proof.One has:dφ∗t(ω)/dt=φ∗t(L Xtsecond,we use the(somewhat non-traditional)definition:[X,Y]=L Y X=dψ∗t X/dt|t=0,and theni([X,Y])ω=di(ψ∗t X)ω/dt|t=0=L Y i(X)ω=di(Y)i(X)ω=dω(X,Y),as claimed.Note that with the definition of the Lie bracket above one has L[X,Y]=−[L X,L Y] (cf.McDuff-Salamon,p.82).For linear symplectomorphisms,we had a relation with quadratic functions.Like-wise,given a(Hamiltonian)function H on M,define its Hamiltonian vectorfield X H by i(X H)ω=dH.In Darboux coordinates,X H=H p∂q−H q∂p.On closed M,this gives a 1-parameter group of symplectomorphisms called the Hamiltonianflow of H.Lemma.The vector X H is tangent to a level hypersurface H=const.Proof.One has:dH(X H)=ω(X H,X H)=0.This lemma is related to the symplectic reduction construction.If S is given by H=const then X H generates the characteristic foliation on S,tangent to thefield of kernels of the restriction ofωto S.Indeed,ω(X H,v)=dH(v)=0once v is tangent to S.Define the Poisson bracket{F,G}=ω(X F,X G)=dF(X G).In Darboux coordinates, the formulas are as in1.5.This bracket satisfies the Jacobi identity;we will deduce it from Darboux theorem.Lemma.The correspondence H→X H is a Lie algebra homomorphism.Proof.We want to show that[X F,X G]=X{F,G}.One has[X F,X G]=−dφ∗t(X G)/dt|t=0=−dX G(φtF )/dt|t=0.Theni([X F,X G])ω=−d(dG(φt F))/dt|t=0=−d(dG(X F))=d({F,G}),as claimed.To summarize,here are the main formulas,in Darboux coordinates:ω=dq∧dp;X H=H p∂q−H q∂p;{H,F}=H p F q−H q F p.Note that the Hamiltonian vectorfield X H is also often called the symplectic gradient of the function H.2.4.Unlike Riemannian manifolds,symplectic manifolds do not have local invariants. Darboux Theorem.Symplectic manifolds of the same dimension are locally symplecto-morphic.Proof.Consider two symplectic manifolds withfixed points(M1,O1,ω1)and (M2,O2,ω2).We want to construct a local symplectomorphism(M1,O1,ω1)→(M2,O2,ω2).First consider a local diffeomorphism(M1,O1)→(M2,O2);now we have two(germs of)symplectic structuresω0,ω1on the same manifold(M,O),and since there is only one symplectic vector space of a given dimension(the linear Darboux theorem),we assume thatω0andω1coincide at point O.Claim:There is a local diffeomorphism f:M→M,fixing O and such that f∗(ω0)=ω1.Consider the familyωt=(1−t)ω0+tω1.This is a symplectic structure for all t∈[0,1] in a small neighborhood of the origin.We need tofind a family of diffeomorphismsφt,fixing O,such thatφ∗tωt=ω0.This is equivalent tofinding a time-dependent symplectic vectorfield X t,related toφt in the usual way,dφt(x)/dt=X t(φt(x)),and vanishing at O, such thatL Xωt+ω1−ω0=0.tChoose a1-formαsuch that dα=ω1−ω0;thisαis defined up to summation with d f. Then we have the equationi(X t)ωt+α=0.This is solvable for allαsinceωt is non-degenerate.It remains to show that X t may be taken trivial at O.For this,we need to replaceαby a1-form that vanishes at O.Every1-form can be locally written asα= x iαi+ c i dx iwhereαi are1-forms and c i are constants.Then we replaceαbyα−d( c i x i),and this 1-form vanishes at O.In fact,a similar homotopy method,due to Moser,applies to a more general situation in which the points O1,O2are replaced by germs of submanifolds N1,N2such that the pairs(N1,ω1|N1)and(N2,ω2|N2)are symplectomorphic.2.5.A Lagrangian submanifold of a symplectic manifold(M2n,ω)is a manifold L n such thatω|L=0.An informal principle is that every symplectically meaningful object is a Lagrangian manifold.Examples.(a)Every curve is Lagrangian in a symplectic surface.(b)Consider T∗M with its canonical symplectic structure,and letαbe a1-form on M.This form determines a sectionγof T∗M whose image is Lagrangian iffαis closed. Indeed,ω|γ(M)=γ∗(ω)=dγ∗(λ)=dα.(c)Let N⊂M be a submanifold.Its conormal bundle P⊂T∗M|N consists of the covectors,equal to zero on N.Then P is Lagrangian.Indeed,choose local coordinates q1,...,q n in M so that q1=...=q k=0is N.Let p,q be the respective coordinates in T∗M.Then P is given by q1=...=q k=0,p k+1=...=p n=0.If N is a point,one obtains a“delta-function”.(d)Let f:(M1,ω1)→(M2,ω2)be a symplectomorphism.Then the graph G(f)is a Lagrangian submanifold in(M1×M2,ω1 ω2).Indeed,consider u1,v1∈T M1,and let u2=Df(u1),v2=Df(v1).Then(u1,u2)and(v1,v2)are two tangent vectors to G(f), and(ω1 ω2)((u1,u2),(v1,v2))=ω1(u1,v1)−ω2(u2,v2)=(ω1−f∗(ω2))(u1,v1)=0.(e)Let N n−1⊂R n be a hypersurface.Consider the set L of oriented normal lines to N;this is a Lagrangian submanifold of the space of oriented lines in R n.To provethis,recall that the space of oriented lines in R n is symplectomorphic to T∗S n−1with its symplectic structure dp∧dq;q∈S n−1,p∈T∗q S n−1.Let n(x)be the unit normal vector to N at point x∈N.Then L is given parametrically by the equationsq=n(x),p=x−(x·n(x))n(x),x∈N.Hencepdq=xdn−(x·n)ndn=xdn=d(x·n)−ndx=d(x·n),where ndn=0since n2=1and ndx=0on N since n is a normal.Therefore dp∧dq=0 on L.The function(x·n(x))is called the support function of the hypersurface N;it plays an important role in convex geometry.Let f:S n−1→R be a support function.How can one construct the corresponding hypersurface N?Claim:N is the locus of pointsy=f(x)x+grad f(x).Indeed,we need to show that x is a normal to N at point y,i.e.,xdy=0.Note that x grad f(x)=0hence x d grad f(x)+grad f(x)dx=0.Note also that x2=1hence xdx=0.Now one has:xdy=fxdx+x2d f+x d grad f(x)=d f−grad f(x)dx=0as needed.Exercise.Let L n−1be a submanifold of the space of oriented lines in R n.When does L consist of lines,orthogonal to a hypersurface?If this is the case,how many such hypersurfaces are there?Exercise.Let f:S1→R be the support function of a closed convex plane curve. Express the following characteristics of the curve in terms of f:curvature,area,perimeter length.Exercise∗.Let L be a Lagrangian submanifold in a symplectic manifold M.Prove that a sufficiently small neighborhood of L in M is symplectomorphic to a neighborhood of the zero section in T∗L.This statement is a version of Darboux theorem,and it can be proved along similar lines.2.6.A Lagrangian foliation is an n-dimensional foliation of a symplectic manifold M2n whose leaves are Lagrangian.Similarly one defines a Lagrangianfibration.An example is given by the cotangent bundle whosefibers are Lagrangian.An affine structure on an n-dimensional manifold is given by an atlas whose transi-tion maps are affine transformations.An affine manifold is complete if every line can be extended indefinitely.Examples include R n and n-torus.Theorem.The leaves of a Lagrangian foliation have a canonical affine structure.Proof.Let M2n be a symplectic manifold,F n a Lagrangian foliation and p:M→N n=M/F the(locally defined)projection.Consider a function F on N and extend itto M as F◦p.Let u be a tangent vector to a leaf.Then dF(u)=0.Therefore X F is skew-orthogonal to the tangent space of the leaf,that is,is tangent to the leaf.Then {F,G}=ω(X F,X G)=0,so the functions,constant on the leaves,Poisson commute.Fix a point x∈N.If F is a function on N such that dF(x)=0then X F=0on the leaf F x.Choose a basis in T∗x N,choose n functions F i whose differentials at x form.These are commuting vectorfields,and we this basis and consider the vectorfields X Fiobtain a locally effective action of R n on F x.This action is well defined if the quotient space N is defined,for example,if F is a Lagrangianfibration.In general,N is defined only locally,and going from one chart to another changes the respective commuting vectorfields by affine transformations.Thus an affine structure on the leaf is well defined.Corollary.If a leaf of a Lagrangian foliation is a closed manifold then it is a torus.Proof.If a leaf is complete then it is a quotient of R n by a discrete subgroup.If the leaf is compact,the subgroup is a lattice Z n.Here is what it boils down to in dimension2.A Lagrangian foliation is given by a function f(x,y):the leaves are the level curves.The function f is defined up to composition with functions of1variable:f→¯f=φ◦f.The vectorfield X f is tangent to the leaves and,on a leaf,one can introduce a parameter t such that X f=∂t.Changing f to¯f, thefield X f multiplies by a constantφ (depending on the leaf),and the parameter t also changes to¯t=ct.This parameter,defined up to a constant,give an affine structure.2.7.A consequence is the so-called Arnold-Liouville theorem in integrable systems. Theorem.Let M2n be a symplectic manifold with n functions F1,...,F n that Poisson commute:{F i,F j}=0.Consider a non-singular level manifold M c={F i=c i,i=1,...,n} and a Hamiltonian function H=H(F1,...,F n).Then M c is a smooth manifold,invariant under the vectorfield X H.There is an affine structure on M c in which thefield X H is constant.If M c is closed and connected then it is a torus.Proof.The mapping(F1,...,F n):M→R is afibration near the value c,and itsare constant in the respective affine coordinates,and leaves are Lagrangian.Thefields X FiX H is a linear combination of these nfields with the coefficients,constant on M c(why?) There is a version of this theorem in which X H is replaced by a symplectomorphismφ: M→M such that F i◦φ=F i for all i.Thenφpreserves M c and the affine structure therein.,and thereforeφis a parallel translation x→Moreover,φpreserves each vectorfield X Fix+c.Corollary.Letφandψbe two symplectomorphisms that preserve the same Lagrangian foliation leafwise.Thenφandψcommute.Proof.Both maps are parallel translations in the same affine coordinate system,and parallel translations commute.2.8.Billiards.An example of a symplectic map is provided by billiards.Considera strictly convex domain M⊂R n with a smooth boundary N n−1.Let U be the space of oriented lines that intersect M;it has a symplectic structure discussed in2.2.Consider the billiard map T:U→U given by the familiar law of geometrical optics:the incomingand outgoing rays lie in one2-plane with the normal at the impact point and make equal angles with this normal.Theorem.The billiard transformation is a symplectic map.Proof.Consider T∗M with its canonical symplectic structureω=dp∧dq where q,p are the usual coordinates.We identify tangent and cotangent vectors by Euclidean structure.Consider two hypersurfaces in T∗M:Y={(q,p)|p2=1},Z={(q,p)|q∈N}.The characteristics of Y are oriented lines in R n(section2.2,example g),and the sym-plectic reduction yields U with its symplectic structure.What are characteristics of Z? Consider the projectionπ:Z→T∗N given by the restriction of a covector on T N.Claim:the characteristics of Z are thefibers of the projectionπ.Indeed,let n(q)be the unit normal vector to N at point q∈N.Then thefibers ofπare integral curves of the vectorfield n(q)∂p.One has:i(n(q)∂p)ω=n(q)dq=0since n is a normal vector.It follows that the symplectic reduction of Z is the space V=T∗N.Let W=Y∩Z,the set of unit vectors with foot point on N.Consider W with the symplectic structureω|W.The projections of W on U and V along the leaves of the characteristic foliations of Y and Z are double coverings.These projections are symplectic mappings(why?)One obtains two symplectic involutionsσandτon W that interchange the preimages of a point under each projection.The billiard map T can be considered as a transformation of W equal toσ◦τ.Therefore T is a symplectomorphism.The proof shows that the billiard map can be also considered as a symplectic trans-formation of T∗N realized as the set of inward unit vectors with foot points on N.Exercise.Let n=2.Denote by t an arc length parameter along the billiard curve and byαthe angle between this curve and and the inward unit vector.The phase space of the billiard map is an annulus with coordinates(t,α).Prove that the invariant symplectic form is sinαdα∧dt.An alternative proof proceeds as follows.Let q1q2be an oriented line,q1,q2∈N.Let p1be the unit vector from q1to q2.The billiard map acts as follows:(q1,p1)→(q2,p2)N.Consider the where the covectors(q2,p1)and(q2,p2)have equal projections on T q2 generating function L(q1,q2)=|q1q2|.Then∂L/∂q1=−p1,∂L/∂q2=p1.Consider the Liouville formλ=pdq and restrict everything on T∗N.Then one has: T∗λ−λ=dL.Thereforeω=dλis T-invariant.Corollary.Billiard trajectories are extrema of the perimeter length function on polygons inscribed into N.Example.It is classically known that the billiard inside an ellipse is integrable:the invariant curves consist of the lines tangent to a confocal conic.Consider two confocal ellipses and the respective billiard transformations T1,T2.It follows from Corollary2.7that T1◦T2=T2◦T1,an interesting theorem of elementary geometry(especially its particular case,“The most elementary theorem of Euclidean geometry”)!Exercise∗.Let N be a smooth hypersurface in R n,and let X be the set of oriented lines in R n with its canonical symplectic structure.Consider the hypersurface Y⊂X that consists of the lines tangent to N.Prove that the characteristics of Y consist of the lines, tangent to a geodesic curve on N.3.Symplecticfixed points theorems and Morse theory.3.1.The next result was published by Poincar´e as a conjecture shortly before his death and proved by Birkhoffin1917.Consider the annulus A=S1×I with the standard area form and its area preserving diffeomorphism T,preserving each boundary circle and rotating them in the opposite directions.This means the a lifted diffeomorphism¯T of the strip S=R×[0,1]satisfies:¯T(x,0)=(X,0)with X>x and¯T(x,1)=(X,1)with X<x. Theorem(Poincar´e-Birkhoff).The mapping T has at least two distinctfixed points.Both conditions,that T is area preserving and that the boundary circles are rotated in the opposite sense,are necessary(why?).Proof.We prove the existence of onefixed point,the hardest part of the argument. Assume there are nofixed points.Consider the vectorfield v(x)=¯T(x)−x,x∈S.Let point x move from lower boundary to the upper one along a simple curveγ,and let r be the rotation of the vector v(x).This rotation is of the formπ+2πk,k∈Z.Note that r does not depend on the arcγ(why?).Note also that T−1has the same rotation r since the vector T−1(y)−y is opposite to T(x)−x for y=T(x).To compute r,letε>0be smaller than|T(x),x|for all x∈A;suchεexists because A is compact.Let Fεbe the vertical shift of the plane throughεand let¯Tε=Fε◦¯T. Consider the strip Sε=R×[0,ε].Its images under¯Tεare disjoint.Since¯Tεpreserves the area,the image of Sεwill intersect the upper boundary.Let k be the least number of needed iterations,and let P k be the upper most point of the upper boundary of this k-th iteration.Let P0,P1,...,P k the respective orbit,P0on the lower boundary of S.Join P0 and P1by a segment and consider its consecutive images:this is a simple arcγ.Forεsmall enough,the rotation r almost equals the winding number of the arcγ.In the limit ε→0,one has:r=π.Alternatively,we have a vectorfield v(x)=x1−x with x1=T(x)alongγ.One can homotop thisfield as follows:for1/2time freeze x at P0and let x1traverseγto P k,and for the other1/2time freeze x1at P k and let x traverseγ.Now consider the map T−1.Unlike T,it moves the lower boundary of S right and the upper one left.By the same argument,its rotation equals−π.On the other hand,by a remark above,this rotation equals that of T,a contradiction.A consequence is the existence of periodic billiard trajectories inside smooth strictly convex closed plane curves.The billiard transformation T is an area preserving map of the annulus A=S1×[0,π](we assume that the length of the curve is1).The map T。
Diophantine tori and spectral asymptotics for non-selfadjoint operators
1
Introduction and statement of main results
Recently there has been a large number of new developments for non-selfadjoint problems. These include semiclassical spectral asymptotics for non-selfadjoint operators in low dimensions [22], [29], [28], [40], [35], resolvent estimates and pseudospectral behavior [15], [13], [6], spectral instability questions [19], [34], and evolution problems and decay to equilibrium for the Fokker-Planck operator [20]. The purpose of this work is to continue a line of development initiated in [28], which opened up the possibility of carrying out a spectral analysis for non-selfadjoint operators in dimension two, that is as precise as the corresponding analysis for selfadjoint problems in dimension one. In [28], it was established that for a wide and stable class of non-selfadjoint operators in dimension two, it is possible to describe all eigenvalues individually in a fixed domain in the complex plane, by means of a Bohr-Sommerfeld quantization condition. The underlying reason for this result is a version of the KAM theorem without small divisors, in a complex domain. The work [28] has been continued in a series of papers [41], [23], [24], [25], all of them done in the context of small non-selfadjoint perturbations of selfadjoint operators, with the important additional assumption that the classical flow of the leading symbol of the unperturbed part should be periodic in some energy shell. While the case of a periodic classical flow is very special indeed, in the aforementioned works, we have already given some applications of the general results to spectral asymptotics for damped wave equations on analytic Zoll surfaces [39], [21], while barrier top resonances for semiclassical Schr¨ odinger operators have been treated in [26]. Now a classical Hamiltonian with a periodic flow can be naturally viewed as a degenerate case of a completely integrable symbol, and an even more general and much more interesting dynamical situation occurs when considering a symbol that is merely close to a completely integrable one. Continuing our previous works, in this case it seems to be of interest to study the spectrum of non-selfadjoint operators that are small perturbations of a selfadjoint operator, whose classical flow is close to a completely integrable one. The present work is the first one where we begin to study this problem, and when doing so, as our starting point, we shall take a general assumption that the real energy surface of the unperturbed leading symbol contains several flow invariant Lagrangian tori satisfying a Diophantine condition.
Non-associative gauge theory and higher spin interactions
a r X i v :h e p -t h /0412027v 2 10 F eb 2005MCTP-04-64QMUL-PH-04-08hep-th/041202702/12/04Non-associative gauge theory and higher spin interactions Paul de Medeiros 1and Sanjaye Ramgoolam 21Michigan Center for Theoretical Physics,Randall Laboratory,University of Michigan,Ann Arbor,MI 48109-1120,U.S.A.2Department of Physics,Queen Mary University of London,Mile End Road,London E14NS,U.K.pfdm@ ,s.ramgoolam@ Abstract We give a framework to describe gauge theory on a certain class of commutative but non-associative fuzzy spaces.Our description is in terms of an Abelian gauge connection valued inthe algebra of functions on the cotangent bundle of the fuzzy space.The structure of such a gauge theory has many formal similarities with that of Yang-Mills theory.The components of the gauge connection are functions on the fuzzy space which transform in higher spin representations of the Lorentz group.In component form,the gauge theory describes an interacting theory of higher spin fields,which remains non-trivial in the limit where the fuzzy space becomes associative.In this limit,the theory can be viewed as a projection of an ordinary non-commutative Yang-Mills theory.We describe the embedding of Maxwell theory in this extended framework which follows the standard unfolding procedure for higher spin gauge theories.1IntroductionWe formulate gauge theory on a certain class of commutative but non-associative algebras, developing the constructions initiated in[1].These algebras correspond to so called fuzzy spaces which reduce to ordinary spacetime manifolds in a particular associative limit.We find that such gauge theories have a realisation in terms of interacting higher spinfield theories.The non-associative algebra of interest A∗n(M)is a deformation of the algebra of func-tions A(M)on a D-dimensional(pseudo-)Riemannian manifold M.The∗denotes a non-associative product for functions on the fuzzy space whilst n∈Z+provides a quantitative measure of the non-associativity(in particular A∗∞=A).For simplicity,we take M=R D withflat metric.Most of our formulas will be independent of the signature of this metric, though we will take it to be Lorentzian in discussions of gauge-fixing etc.Furthermore, although we focus on the deformation for R D,there is a conceptually straightforward gener-alisation for curved manifolds.For example,the deformation A∗n(S2k)has been used in the study of even-dimensional fuzzy spheres in[2].In section2we define the commutative,non-associative algebra A∗n(R D)which deforms A(R D),and give the derivations of this algebra.In this review,we recall that the associator(A∗B)∗C−A∗(B∗C)of three functions A,B and C on A∗n(R D)can be written as an operator F(A,B)acting on C or as an operator E(A,C)acting on B.These operators have expansions in terms of derivations of the algebra(given in Appendix B)and naturally appear when one attempts to construct covariant derivatives for the gauge theory.Wefind that an inevitable consequence of this structure is that the connection and gauge parameter have to be generalised such that they too have derivative expansions(i.e.they can be understood as functions on the deformed cotangent bundle A∗n(T∗R D)).The infinite number of component functions in these expansions transform as totally symmetric tensors under the Lorentz group.Consequently wefind that this extended gauge theory on A∗n(T∗R D)is related to higher spin gauge theory on A∗n(R D).The local and global structure of this extended gaugetheory is analysed in section3.We observe that the extended gauge theory remains non-trivial even in the limit where the non-associativity parameter goes to zero.In section4we describe certain physical properties in this associative limit.In particular we construct a gauge-invariant action andfield equations for the extended theory using techniques related to the phase space formulation of quantum mechanics initiated by Weyl[20]and Wigner[21].The infinite number higher spin components of the extended gaugefield become just tensors on R D in the associative limit.We describe various aspects of the extended theory in component form in order to make the connection with higher spin gauge theory more explicit.From this perspective it will be clear that the extended theory(as we have presented it)does not realise all the possible symmetries of the corresponding higher spin theory on R D.We suggest that it could describe a partially broken phase of some fully gauge-invariant theory. We then compare the structure wefind with that of the interacting theory of higher spin fields discovered by Vasiliev[14].A precise way to embed Maxwell theory in the extended theory is given.The method is identical to the unfolding procedure which has been used by Vasiliev in the context of higher spin gauge theories[16].It can also be understood simply via a change of basis in phase space under a particular symplectic transformation.In section5we describe how the extended theory in the associative limit described in section 4is related to a projection of an ordinary non-commutative Yang-Mills theory.We also describe connections to Matrix theory.We then discuss how one might generalise the results of section4to construct a gauge-invariant action for the non-associative theory.Section6 contains some concluding remarks.2The non-associative deformation A∗nWe begin by defining the non-associative space of interest.Following[1],we consider the commutative,non-associative algebra A∗n(R D)which is a specific deformation of the commu-tative,associative algebra of functions A(R D)on R D(which is to be thought of as physical spacetime in D dimensions).Another space that will be important in forthcoming discus-sions is the algebra of differential operators acting on A∗n(R D).This algebra is isomorphic to the deformed algebra A∗n(T∗R D)of functions on the(flat)cotangent bundle T∗R D.This correspondence will be helpful when we come to consider gauge theory on A∗n(R D).The space R D has coordinates xµandflat metric.The Euclidean signature metricδµνarises most directly in the Matrix theory considerations motivating[1]but the algebra can be continued to Lorentzian signature by replacing this with Lorentzian metricηµν.The algebraic discussion in this and the next section(and in the appendices)works equally well in either signature,but some additional subtleties related to gauge-fixing discussed in section4are specific to the Lorentzian case.The deformed algebra A∗n(R D)is spanned by the infinite set of elements{1,xµ,xµ1µ2,...}1,where each xµ1...µs transforms as a totally symmetric tensor of rank s under the Lorentz group.The commutative(but non-associative) product∗for all elements xµ1...µs is defined in[1]and Appendix B(this appendix also defines a more general set of products with similar properties to∗).The explicit formula is rather complicated but the important point is that xµ1...µs∗xν1...νt equals xµ1...µsν1...νt up to theaddition of lower rank elements with coefficients proportional to inverse powers of n(for example xµ∗xν=xν∗xµ=xµν+11In[1],the elements x were called z and the deformed algebra A∗(R D)was called B∗n(R D).nnot break Lorentz symmetry.One can define derivations∂µof A∗n(R D)via the rule∂µxµ1...µs=sδ(µ1µxµ2...µs),(1) where brackets denote symmetrisation of indices(with weight1)2.This definition implies that∂µsatisfy the Leibnitz rule when acting on∗-products of elements of A∗n(R D).This Leibnitz property also holds with respect to the more general commutative,non-associative products described in Appendix B.It is clear that composition of these derivations is a commutative and associative operation.In the associative n→∞limit,∂µjust act as the usual partial derivatives on R D.2.1FunctionsFunctions of the coordinates xµ1...µs are written A(x)∈A∗n(R D).Such functions form a commutative but non-associative algebra themselves with respect to the∗multiplication.A quantitative measure of this non-associativity is given by the associator[A,B,C]:=(A∗B)∗C−A∗(B∗C)(2) for three functions A,B and C.Since A∗n(R D)is commutative then the associator(2)has the antisymmetry[A,B,C]=−[C,B,A].The associator also satisfies the cyclic identity [A,B,C]+[B,C,A]+[C,A,B]≡0.An important fact noted in[1]is that such associators can be written as differential operators involving two functions acting on the third.In particular,one can define the two operators E(A,B)and F(A,B)via[A,B,C]=:E(A,C)B=:F(A,B)C.(3) The antisymmetry property of the associator implies E(A,B)=−E(B,A)and the cyclic identity implies F(A,B)−F(B,A)=E(A,B).These operators have the following derivativeexpansions(see[1]or Appendix B)E(A,B)=∞s=11s!(Fµ1...µs(A,B))(x)∗∂µ1...∂µs,(4)where the coefficients Eµ1...µs(A,B)and Fµ1...µs(A,B)are both polynomial functions of the algebra transforming as totally symmetric tensors under the Lorentz group3.The properties quoted above follow for each of these coefficients so that Eµ1...µs(A,B)=−Eµ1...µs(B,A)and Fµ1...µs(A,B)−Fµ1...µs(B,A)=Eµ1...µs(A,B).The reason there are no s=0terms in(4)is that the associators[A,1,C]and[A,B,1]are both identically zero.Thus since(4)are valid as operator equations on any function then including such zeroth order terms in(4)would imply their coefficients are identically zero by simply acting on a constant function.Thefirst non-vanishing s=1coefficients in(4)can be expressed rather neatly as associators,such that Eµ(A,B)=[A,xµ,B]and Fµ(A,B)=[A,B,xµ].In a similar manner,all subsequent s>1coefficients in(4)can also be expressed in terms of(sums of)associators of A and B with coordinates xµ1...µs(though we do not give explicit expressions as they are unnecessary). An important point to keep in mind is that E(A,B)and F(A,B)vanish in the associative limit as expected.The algebra of the differential operators in(4)closes under composition and is non-associative (following non-associativity of A∗n(R D))but it is also non-commutative.Since E(A,B)and F(A,B)vanish in the associative limit the algebra of these operators becomes trivially com-mutative when n→∞.As will be seen in the next subsection,more general differential operators acting on A∗n(R D)also close under composition to form a non-commutative,non-associative algebra.However,this more general algebra remains non-commutative(but as-sociative)when n→∞.For example,the commutator subalgebra of differential operators acting on R D corresponding to sections of the tangent bundle T R D(i.e.vectorfields over R D)is non-Abelian(even though R D is itself commutative).Indeed this is often how oneconsiders simple non-commutative geometries–as Hamiltonian phase spaces of ordinary commutative position spaces(see e.g.[19]).We will draw on this analogy when we come to construct a gauge theory on A∗n(R D).2.2Differential operatorsGeneral differential operators acting on A∗n(R D)are writtenˆA=∞ s=01the algebra of functions is commutative).The definitions(6)obey the identitiesˆE(ˆA,ˆB)≡−ˆE(ˆB,ˆA)andˆF(ˆA,ˆB)−ˆF(ˆB,ˆA)≡ˆE(ˆA,ˆB)+[ˆA,ˆB](where[ˆA,ˆB]:=ˆAˆB−ˆBˆA is just thecommutator of operators).These reduce to the identities found earlier in terms of functions whenˆA=A andˆB=B.In the associative limit,notice thatˆF(ˆA,ˆB)vanishes identically whilstˆE(ˆA,ˆB)reduces to the commutator[ˆB,ˆA].The explicit derivative expansion forˆE(ˆA,ˆB)is given in Appendix A for later reference (the corresponding expression forˆF(ˆA,ˆB)will not be needed).We should just conclude this review of the relevant algebras associated with A∗n(R D)by noting that,unlike(4),the operator expression forˆE(ˆA,ˆB)includes a non-vanishing zeroth order algebraic term.It is easy to see that this is so by considering C in(6)to be the constant function.In this case all derivative terms inˆE(ˆA,ˆB)on the left hand side vanish whilst the right hand side reduces to the non-vanishing functionˆBA−ˆAB(where A and B are the zeroth order parts ofˆA and ˆB respectively).Thus the zeroth order partˆE(ˆA,ˆB)=ˆBA−ˆAB,which vanishes when(0)ˆA=A andˆB=B as expected.3Non-associative gauge theoryWe begin this section by reviewing the subtleties raised in[1]associated with formulating an Abelian gauge theory on A∗n(R D).We show that a naive formulation is not possible on this non-associative space.Instead it is rather natural to consider an extension of such an Abelian gauge theory on the deformed algebra A∗n(T∗R D)of functions on the cotangent bundle.We describe the local and global gauge structure of this non-associative extended theory.We find the structure to be similar to that of a Yang-Mills theory with infinite-dimensional gauge group.We will return to the question of embedding an Abelian gauge theory on A∗n(R D)in this extended structure in later sections.3.1Abelian gauge theory on A∗n(R D)A necessary ingredient in the construction of any gauge theory is the concept of a gauge-covariant derivative.Consider afieldΦwhich is a function of A∗n(R D)and define it to have the infinitesimal gauge transformation lawδΦ=ǫ∗Φ,(7)whereǫis an arbitrary polynomial function of A∗n(R D).(One reason for the choice of(7)is that it is reminiscent of the infinitesimal gauge transformation for afield in the fundamental representation of the gauge group in ordinary Yang-Mills theory.)An operator Dµthat is covariant with respect to(7)must therefore obeyδ(DµΦ)=ǫ∗(DµΦ).(8)Clearly the derivation∂µ(1)alone does not obey this covariance requirement sinceδ(∂µΦ)=ǫ∗(∂µΦ)+(∂µǫ)∗Φ.To compensate we must introduce a gauge connection Aµ,which we take to be a function on A∗n(R D)and which transforms such thatδ(Aµ∗Φ)=ǫ∗(Aµ∗Φ)−(∂µǫ)∗Φ.Clearly the existence of such an Aµwould imply thatDµΦ:=∂µΦ+Aµ∗Φ(9) indeed defines a covariant derivative on functions,satisfying(8).Using(7)then implies that we require Aµto transform such that(δAµ)∗Φ=−(∂µǫ)∗Φ+ǫ∗(Aµ∗Φ)−Aµ∗(ǫ∗Φ).(10) In ordinary gauge theory(10)would allow one to simply read offthe necessary gauge transfor-mation for Aµbut here things are more complicated due to non-associativity.In particular, notice that the last two terms in(10)can be written as the associator[Aµ,Φ,ǫ]and therefore, using(3),we requireδAµ=−(∂µǫ)+E(Aµ,ǫ).(11) This requirement,however,leads to a contradiction since thefirst two terms in(11)are algebraic functions on A∗n(R D)whilst(4)tells us that the third term acts only as a differentialoperator on A ∗n (R D ).Therefore such an A µcan only exist when E (A µ,ǫ)=0,i.e.in theassociative limit where this would simply be an Abelian gauge theory on R D !As indicated in[1],themost conservative way to proceed is therefore to simply generalise thegauge connection A µfrom an algebraic function to a differential operator ˆAµwith derivative expansionˆA µ=∞ s =01s !ǫα1...αs (x )∗∂α1...∂αs .(13)As noted already,the algebra of such operators is both non-associative and non-commutative.Consequently we must take care when revising the arguments of this subsection in terms of these extended fields.This revised analysis is described,in the next subsection,within the framework of global gauge transformations for the extended theory.In concluding,it is important to stress that the generalisation we have made is a modification of the original theory and therefore the extended theory need not trivially reduce to an Abelian gauge theory on R D in the associative limit.(Notice that the s >0terms in (12)and (13)do not vanish as n →∞.)Indeed we will find it does not though we will give a precise way to embed the Abelian theory in its extension on R D .3.2Global structureConsider again afieldΦwhich is a function of A∗n(R D)but now with infinitesimal gauge transformation lawδΦ=ˆǫΦ,(14) whereˆǫis the extended differential operator(13).Formally this is similar to Yang-Mills theory where one then obtains the global gauge transformation by exponentiating the lo-cal(Lie algebra valued)gauge parameter to obtain a general Lie group element(or more precisely the fundamental representations of these quantities).The main difference here is that the algebra of local gauge transformations(14)is non-associative.Despite this,given a general differential operatorˆǫ,there still exists a well-defined exponential exp(ˆǫ)[18].The construction essentially just follows the power series definition of the exponential map for matrix algebras but here one must choose an ordering for powers ofˆǫ(so as to avoid the potential ambiguities due to non-associativity).We follow[18]and define powers via a‘left action’rule so thatexp(ˆǫ)Φ:=Φ+ˆǫΦ+13!ˆǫ(ˆǫ(ˆǫΦ))+...,(15)for any functionΦ.It is then clear that the exponentiated operatorˆg:=exp(ˆǫ)is also a differential operator acting on the algebra(albeit a rather complicated function ofˆǫ)and we define the‘global’transformation ofΦto beΦ→ˆgΦ.(16)This transformation obviously reduces to(14)in some neighbourhood of the identity where ˆg=1+ˆǫ(the‘identity’here is the unit element of A∗n(R D)).The set of all transformations (16)does not quite form a group under left action composition since it fails to satisfy the associativity axiom(due to non-associativity of the algebra).However,all the other group axioms are satisfied4.The derivation∂µis not covariant with respect(16)since this transformation implies∂µΦ→[∂µ,ˆg]Φ+ˆg(∂µΦ).As noted at the end of the previous subsection,we therefore introduce a gauge connectionˆAµwhich must transform such thatˆAµΦ→−[∂µ,ˆg]Φ+ˆg(ˆAµΦ)in order thatˆDΦ:=∂µΦ+ˆAµΦ(17)µtransforms covariantly under(16).This necessary gauge transformation ofˆAµΦunder(16) can be realised provided the gauge transformation ofˆAµis defined such thatˆAΦ→−[∂µ,ˆg](ˆg−1Φ′)+ˆg(ˆAµ(ˆg−1Φ′))(18)µunder the more general function transformationΦ→Φ′.This gives the desired gauge transformation whenΦ′=ˆgΦ.One can obtain the gauge transformation ofˆAµitself by using the operatorˆF(6)to rearrange the brackets in(18).In particular,notice that the right hand side of(18)can be written−[∂µ,ˆg]+ˆgˆAµ−ˆF(ˆg,ˆAµ) (ˆg−1Φ′)(19) = −[∂µ,ˆg]+ˆgˆAµ−ˆF(ˆg,ˆAµ) ˆg−1 Φ′−ˆF −[∂µ,ˆg]+ˆgˆAµ−ˆF(ˆg,ˆAµ) ,ˆg−1 Φ′. ThereforeˆAµmust have the following gauge transformationˆAµ→ −[∂µ,ˆg]+ˆgˆAµ−ˆF(ˆg,ˆAµ) ˆg−1−ˆF −[∂µ,ˆg]+ˆgˆAµ−ˆF(ˆg,ˆAµ) ,ˆg−1 .(20) Settingˆg=1+ˆǫin(20)leads to the infinitesimal form of the gauge transformationδˆAµ=−[∂µ,ˆǫ]+ˆE(ˆAµ,ˆǫ).(21) Of course,at the infinitesimal level,this transformation equivalently follows by the require-ment thatδ(ˆDµΦ)=ˆǫ(ˆDµΦ)under(14).Notice that(20)and(21)do not quite take the form one would expect by naively following the Yang-Mills analogy(that is they differ from what one might expect by associator terms). This is a consequence of the non-associativity of the underlying algebra of functions.In the following section we willfind that the expected Yang-Mills type structure follows exactly in the associative limit.In the discussion above we have only defined covariant derivativesˆDµon functions and not on differential operators.Although not of the standard Yang-Mills form,(minus)the right hand side of(21)can still be taken as the definition for the action of the covariant derivative on operatorˆǫ,such thatˆDµ·ˆǫ:=[∂µ,ˆǫ]+ˆE(ˆǫ,ˆAµ).(22) This statement is partially justified by the fact thatˆDµthen satisfies the Leibnitz rule ˆD(ˆǫΦ)=(ˆDµ·ˆǫ)Φ+ˆǫ(ˆDµΦ)(for general operatorˆǫand functionΦ)5.µBased on the transformation law found above,we define thefield strengthˆFµνasˆF:=ˆE(ˆDν,ˆDµ)=[∂µ,ˆAν]−[∂ν,ˆAµ]+ˆE(ˆAν,ˆAµ).(23)µνIt is clear from this definition thatˆFµνis indeed a differential operator which transforms as a two-form under the Lorentz group.In addition,since the gauge transformations above imply thatˆDΦ→ˆg(ˆDµ(ˆg−1Φ′)),(24)µunder(18),then it follows thatˆFµνΦ=ˆDµ(ˆDνΦ)−ˆDν(ˆDµΦ)transforms asˆFΦ→ˆg(ˆFµν(ˆg−1Φ′)),(25)µνand is therefore also gauge-covariant whenΦ′=ˆgΦ.The infinitesimal form of the covariant gauge transformation ofˆFµνisδˆFµν=ˆE(ˆFµν,ˆǫ).(26)From the evidence above,it is clear that there are various subtleties related to the non-associative nature of the theory.Indeed the non-associativity complicates matters even further in the description of more physical aspects of the theory like Lagrangians,field equations and the embedding of an Abelian gauge theory in this extended framework.Recall though that this extended theory should have a non-trivial structure,even in the associative limit.We therefore postpone further discussion of the non-associative extended theory to analyse its associative limit in more detail.4Gauge theory on T∗R D and higher spin gauge theory on R DWe begin this section by briefly summarising the results of the previous subsection in the associative limit.We then describe how one can construct a gauge-invariant action and equations of motion for this theory.Writing the extended gaugefieldˆAµin terms of com-wefind that the extended theory describes an interacting theory ponent functions Aα1...αsµinvolving an infinite number of higher spinfields.When written in component form,it will be clear that the extended theory(as we have described it)does not realise all the possible symmetries of the corresponding higher spin gauge theory.We suggest that the extended theory could correspond to a partially broken phase of some fully gauge-invariant higher spin theory.A comparison of the structure wefind with that of the interacting theory of higher spinfields discovered by Vasiliev[14]is then given.We conclude the section by showing how an Abelian gauge theory can be embedded in this extended framework.The embedding is related to the unfolding procedure used by Vasiliev in the context of higher spin gauge theory[16].134.1The associative limitMany expressions found in the previous section retain their schematic form in the associative limit.For example,the gauge transformations for functions are just as in(14),(16)though Φis now simply a function on R D whilst operators likeˆǫin(13)now have the expansionˆǫ=∞ s=01also transforms covariantly.The infinitesimal form of this covariant transformation beingδˆFµν=[ˆǫ,ˆFµν].(32)4.2Action andfield equationsA simple equation of motion to consider for the extended theory in the associative limit is[ˆDµ,ˆFµν]=0.(33)This is thefield equation one would expect from following the Yang-Mills type structure found for the extended theory in the previous subsection.The equation(33)is invariant under the gauge transformation(28).Moreover it is this equation(rather than,say,the also gauge-invariant equationˆDµˆFµν=0)which reduces to the correct Maxwell equation as we will see in section4.5.Following the Yang-Mills analogy further,a natural gauge-invariant action to consider is of the form−1taking the usual gauge-invariant trace(using the Cartan-Killing metric for the gauge group) followed by integrating over spacetime.However,we do not assume a priori that the map(35)can be factorised in thisway6.In the Yang-Mills case the symmetry property of Trsimply follows from the fact that the trace is symmetric.The symmetry of the trace is a rather general property offinite-dimensional representations–as one considers for Yang-Mills theories with compact gauge groups–since such representations can be expressed in terms offinite-dimensional square matrices(and for two such matrices X,Y,the trace of XY is just X i j Y j i=Y i j X j i).For the extended theory we are considering thoughfields are valued in the algebra of differential operators on R D and the situation is very different for the case of such infinite-dimensional representations.For example,in quantum mechanics, if the Heisenberg algebra[ˆx,ˆp]=i had any representations offinite dimension n=0(and hence a symmetric trace)then it would imply the well-known contradiction0=in!The example above is quite pertinent since we will now show thatfields in the extended theory we are considering are related to certain functions in the formulation of quantum mechanics based on the original work of Weyl[20]and Wigner[21]which was later developed by Groenewold[23]and Moyal[24](see[27]for a nice review).Within this framework,there exists a natural concept of the symmetric map Tr.In terms of the abstract canonically conjugate operatorsˆxµandˆpµ,a general operatorˆA of the form(27)is writtenˆA=A(ˆx,ˆp)=∞ s=0i s6As explained in[19],non-commutative gauge theories provide a counter example where such a factori-sation of Tr is not possible.16ordering prescription above7.Given this ordering rule,the Weyl homomorphism[20]says that every operator A(ˆx,ˆp)(37) is naturally associated with an ordinary c-number function˜A on the classical phase space R2D(spanned by coordinates(x,p)),such that1A(ˆx,ˆp)=(2π)2D dy dq dx dp˜A(x,p)yα1...yαs exp(i qµ(ˆxµ−xµ)−i yµpµ).(39) The trace Tr of the operator A(ˆx,ˆp)is defined byTr(ˆA):= dx dp˜A(x,p).(40) This integral is only defined for functions˜A with suitably rapid asymptotic decay properties. We will describe a particular Wigner basis for a class of such integrable functions in the next subsection.The inverse of the relation(38)can then be expressed in terms of this trace,such that˜A(x,p)=1−→∂∂pµ(−i)m ∂∂pµm˜A ∂∂xµm˜B .(43)m!Notice in particular that the m=0term in(43)is just the commutative classical product of functions˜A˜B.The m>0terms are not commutative but are invariant under the combined exchange˜A↔˜B and x↔p.Equation(43)implies that xµ⋆pν=xµpνandpν⋆xµ=xµpν−iδµν,thus confirming that the⋆-product of functions preserves the structureof the Heisenberg algebra.It is also worth noting that partial derivatives(with respect tox or p)act as derivations on the algebra of classical phase space functions with⋆-product since they obey the Leibnitz rule when acting on(43).The definition(43)implies thatdx dp(˜A⋆˜B)(x,p)= dx dp˜A′(x,p)˜B′(x,p)= dx dp(˜B⋆˜A)(x,p),(44)where the primed phase space functions denote˜A′:=exp i∂xµ∂2∂∂pµ ˜B which are just multiplied with respect to the classical product in(44).Thus the trace(40)of the operator productˆAˆB is indeed symmetric,as required.The precise form of the gauge-invariant action(34)is therefore given by−14 dx dp˜F′µν(x,p)˜F′µν(x,p),(45) where the function˜F′µν:=exp i∂xµ∂4.2.1Wigner basis for integrable functionsWe will now briefly describe a particular basis for a class of classical functions which have finite integrals over phase space(a more detailed review of this construction is given in[27]). This will show us how to restrict to the class of Weyl-dual operators for which the trace map Tr is well-defined.Of course,this is necessary so that the gauge-invariant action(45)exists.Consider a complete orthonormal basis of eigenfunctions{ψa}for a given Hamiltonian H. To each such eigenfunctionψa(x)on R D,there is an associated Wigner function1f a(x,p)=proportional to exp −i ∂x µ∂4(2π)4D dxdp dydq dy ′dq ′exp −i 4(2π)2D dy dq exp (−i y µq µ)×Tr exp(−i q µˆx µ)ˆF αβexp(−i y µˆp µ) Tr exp(i q µˆx µ)ˆF αβexp(i y µˆp µ)。
Acyclic
k=0
(t) :=
+
1 X
The noncommutative symmetric functions k are called elementary functions. On the other hand, k and k are respectively called power sums of the rst and second kind. 2
F I = Fi1 Fi2 : : : F i
1 2
r
for every composition I = (i ; i ; : : : ; ir). The families (S I ), ( I ), ( I ) and ( I ) all form homogeneous bases of Sym. The set of all compositions of a given integer n is equipped with the reverse re nement order, denoted . For instance, the compositions J of 4 such that J (1; 2; 1) are exactly (1; 2; 1), (3; 1), (1; 3) and (4). The noncommutative ribbon Schur functions (RI ) can then be de ned by one of the two equivalent relations X X SI = RI ; R I = (?1)` I ?` J S J ;
k=1
k?1 kt
ቤተ መጻሕፍቲ ባይዱ
;
(t) :=
itopologicaloperator symmetricdifference 用法
itopologicaloperatorsymmetricdifference 用法ITopologicalOperator接口中的SymmetricDifference 方法用于产生两个几何图形的对称差分,即两个几何的并集部分减去两个几何的交集部分。
具体用法如下:创建一个ITopologicalOperator对象,该对象用于执行空间拓扑运算。
指定要使用的几何对象,通常包括源对象和参与运算的几何对象。
调用SymmetricDifference方法,将源对象和参与运算的几何对象作为参数传递给该方法。
SymmetricDifference方法将返回一个新的几何对象,表示源对象和参与运算的几何对象的对称差分结果。
以下是使用SymmetricDifference方法的示例代码:java复制代码// 创建源对象和参与运算的几何对象IGeometry sourceGeometry = new Polygon(new Coordinate[] { new Coordinate(0, 0), new Coordinate(10, 0), new Coordinate(10, 10), new Coordinate(0, 10) });IGeometry otherGeometry = new Polygon(new Coordinate[] { new Coordinate(5, 5), new Coordinate(15, 5), new Coordinate(15, 15), new Coordinate(5, 15) });// 创建ITopologicalOperator对象ITopologicalOperator topologicalOperator = new TopologicalOperatorClass();// 执行对称差分运算IGeometry symmetricDifference = topologicalOperator.SymmetricDifference(sourceGeo metry, otherGeometry);// 输出结果System.out.println("Symmetric Difference: " + symmetricDifference.ToString());请注意,上述代码中的ITopologicalOperator、IGeometry等类和接口的具体实现可能会因所使用的GIS库或框架而有所不同。
喷涂机器人静电旋杯的新模型
喷涂机器人静电旋杯的新模型刘洋;赵臣;王旭浩;张佳俊【摘要】旋杯的累积速率模型以及涂料投射模型是喷涂机器人离线编程轨迹规划的重要基础.针对累积速率模型,建立了一种新的模型——双偏置β模型,该模型既能表示满月形模型,也能表示局部非对称的圆环形模型.在此基础上,分析了新模型的匀速喷涂厚度模型,为离线编程的轨迹规划做准备;针对涂料投射模型,推导出了涂料投射模型为任意函数模型时,工件曲面上某点累积速率与基准面上对应点累积速率的关系,并结合实验数据构建了基于正态分布的曲线投射模型.经证明,此模型更符合实际情况.【期刊名称】《中国机械工程》【年(卷),期】2019(030)006【总页数】8页(P709-715,747)【关键词】喷涂机器人;离线编程;累积速率模型;双偏置β模型;涂料投射模型【作者】刘洋;赵臣;王旭浩;张佳俊【作者单位】天津大学机械工程学院,天津,300350;天津大学机械工程学院,天津,300350;天津大学机械工程学院,天津,300350;天津大学机械工程学院,天津,300350【正文语种】中文【中图分类】TP242.20 引言旋杯的涂层累积速率模型[1](简称累积模型)、匀速喷涂厚度模型及涂料投射模型[2]是喷涂机器人离线编程中漆膜厚度计算与轨迹规划环节的重要基础。
在计算自由曲面上某点漆膜厚度时,首先需要求得该点(某时刻)的累积速率,然后积分求得总的漆膜厚度,而该点(某时刻)的累积速率则需要根据基准面上的累积速率模型以及涂料投射模型推导计算而来,因此旋杯的累积速率模型、投料投射模型是漆膜厚度计算的重要基础;而在进行轨迹规划的时候,需要确定两条轨迹的最优间距,以达到喷涂均匀的目的,而最优间距则由旋杯的(累积速率模型所对应的)匀速喷涂厚度模型决定,因此旋杯的累积速率模型、匀速喷涂厚度模型是轨迹规划的重要基础。
旋杯的涂层累积速率模型分为非圆环形(也称为满月形)与圆环形。
现有文献中关于满月形累积模型较多,如:无限范围的高斯分布模型[3]与柯西分布模型[4];有限范围的β分布模型[5]、椭圆双β分布模型[6]、分段函数模型[7]、曲面上的3D模型[8-9]以及与喷涂工艺相结合的多变量模型[10-11]等。
- 1、下载文档前请自行甄别文档内容的完整性,平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益,请联系客服反馈,我们会尽快为您处理(人工客服工作时间:9:00-18:30)。
def def
g ∈ GL(p + q, R g ∈ GIpq g=Ipq detg=1 gt Ipq g=Ipq detg=1
, , ,
(3) (4) (5)
def
g t J p + q g =J p + q g ∈ GL(2(p + q ), C ) gt K pq g=Kpq 2
1
Introduction
In theories of quantum fields (for example, in higher-derivative quantum gravity) one has to deal with the product of two (or more) elliptic differential operators. It is natural, therefore, to investigate multiplicative properties of the determinants of differential operators, in particular the so–called multiplicative anomaly [1, 2] (for the definition of this anomaly see Sect. 3 below). The multiplicative anomaly can be expressed by means of the non–commutative residue associated with a classical pseudo–differential operator, the Wodzicki residue [3]. Recently, the important role of this residue has been recognized in physics. The Wodzicki residue, which is the unique extension of the Dixmier trace to the wider class of pseudo-differential operators [4, 5], has been considered within the non–commutative geometrical approach to the standard model of the electroweak interactions [6, 7, 8, 10, 9, 11]. This residue is also used to write down 1
ℓ
nℓ (χ){λℓ + b}−s ,
(1)
here b is arbitrary constant (endomorphism of the vector bundle V (X )), called in the physical literature the potential term. ζ (s|L) is a well–defined analytic function for ℜs > dim(X )/2, and can be analytically continued to a meromorphic function on the complex plane C , regular at s = 0. The following representations of X up to local isomorphism can be chosen SO1 (n, 1)/SO(n) (I) SU (n, 1)/U (n) (II) X= (2) SP (n, 1)/(SP (n) ⊗ SP (1)) (III) , F4(−20) /Spin(9) (IV) where dim X = n, 2n, 4n, 16, respectively. Then (see for detail [17]) SO(p, q ) = SU (p, q ) = SP (p, q ) =
the Yang-Mills action functional. The residue formulas have also been employed for dealing with the structure of spectral functions related to operators acting in locally symmetric spaces [12, 13], singularity of the zeta functions [14], and the commutator anomalies of current algebras [15]. Other recent papers along these lines can be found in Refs. 15. The purpose of the present paper is to investigate the global multiplicative properties of invertible elliptic operators of Laplace type acting on a non–compact symmetric space, and related zeta functions.
where In is the identity matrix of order n and Ipq = −Ip 0 0 Iq , Jn = 0 In −In 0 , Kpq = Ipq 0 0 Ipq . (6)
The groups SU (p, q ), SP (p, q ) are connected; the group SO1 (p, q ) is defined as the connected component of the identity in SO(p, q ) while F4(−20) is the unique real form of F4 with Dynkin diagram − = − (7)
2
The Spectral Functions
We shall be working with irreducible rank one symmetric space X = G/K of non–compact type. Thus G will be connected non–compact simple split rank one Lie group with finite center and K ⊂ G will be maximal compact subgroup. Let Γ ⊂ G be discrete, co-compact, torsion free subgroup. Let L : C ∞ (V (X )) → C ∞ (V (X )) be partial differential operators acting on smooth sections of vector bundles V (X ). Let χ be a finite–dimensional unitary representation of Γ, let {λℓ }∞ ℓ=0 be the set of eigenvalues of the second–order operator of Laplace type L = −∆Γ acting on smooth sections of the vector bundle over Γ\X induced by χ, and let nℓ (χ) denote the multiplicity of λℓ . We need further a suitable regularization of the determinant of a differential operator, since the naive definition of the product of eigenvalues gives rise to a badly divergent quantity. We make the choice of zeta-function regularization. The zeta function associated with the operators L ≡ L + b has the form ζ (s|L) =
π 2
(8)
while the constant CG and the polynomials P (r) (are even polynomials with Miatello coefficients a2ℓ [19, 20, 21, 22, 17, 13]) are given in the Table 1.