## 数学代写|黎曼曲面代写Riemann surface代考|MTH3022

statistics-lab™ 为您的留学生涯保驾护航 在代写黎曼曲面Riemann surface方面已经树立了自己的口碑, 保证靠谱, 高质且原创的统计Statistics代写服务。我们的专家在代写黎曼曲面Riemann surface代写方面经验极为丰富，各种代写黎曼曲面Riemann surface相关的作业也就用不着说。

• Statistical Inference 统计推断
• Statistical Computing 统计计算
• (Generalized) Linear Models 广义线性模型
• Statistical Machine Learning 统计机器学习
• Longitudinal Data Analysis 纵向数据分析
• Foundations of Data Science 数据科学基础

## 数学代写|黎曼曲面代写Riemann surface代考|THE MAIN LEMMA

In this section we will count the cells in the chains $\varphi, \tau$, and $\psi$ that were defined in the previous section. Note that
$$\begin{gathered} \varphi=\sum_r(A K)^r \eta \ \tau=\sum_r(-K A)^r H \varphi \ \psi=\sum_r(-K A)^r K \nu \end{gathered}$$
We will show that the number of nondegenerate cubical cells in one of these chains is bounded by $C^n$, by parametrizing the cells with trees.

Suppose $z$ is a point in $Z_I$, with $|I|=n$. Consider the chain $F(K A)^r z$. It is a sum of cells of the form
$$F K_{k_r} \alpha_r \ldots K_{k_1} \alpha_1 z$$
Each of these cells is an $r$-cube. Our main construction will be to describe the points in these cells using graphs (which are trees).

Fix a sequence $\alpha_1, \ldots, \alpha_r$. In particular there is a sequence of indices $I=$ $I_0, I_1, \ldots, I_r$ such that $\alpha_j: I_{j-1} \rightarrow I_j$. We will associate a graph to this choice as follows. The vertices are arrayed in $r+1$ rows, with the top row having $n+2$ vertices and bottom row having $n+r+2$ vertices. The $j$ th row from the top has $n+j+2$ vertices. The vertices are numbered from right to left in each row, beginning with 0 , and we denote the $k$ th vertex in the $j$ th row by $v_{j k}$. The vertices at the ends of the rows, $v_{j 0}$ and $v_{j(n+j+1)}$, are called side vertices. The edges of the graph go from vertices in one row to vertices in the next. There is an edge connecting $v_{j-1 i}$ to $v_{j k}$ if and only if $\alpha_j^{+}(k)=i$. Thus in each row except the bottom one, there is exactly one vertex with two edges emanating from below, and all of the other vertices have one edge below. The edges, when drawn as straight lines, do not intersect, because the maps $\alpha^{+}$ are order preserving. The edges drawn from $v_{j 0}$ to $v_{j+10}$ and from $v_{j(n+j+1)}$ to $v_{(j+1)(n+j+2)}$ are called side edges.

## 数学代写|黎曼曲面代写Riemann surface代考|THE MAIN LEMMA

We can decompose the graph into strands, with the strands joining forks. The forks are the vertices which are connected to three edges (in other words the vertices $v_{j k}$ such that $\alpha_{j+1}^{+}(k)=\alpha_{j+1}^{+}(k+1)=k$ ), as well as, by convention, the top and bottom vertices. The strands are the unbroken sequences of edges joining forks, in other words the sequences of edges which meet at interior vertices with only two edges. Side strands are those consisting of side edges. The graph formed by the forks and strands considered as vertices and edges, is a union of binary trees. If a number is assigned to each non-side edge, then one obtains a number for each non-side strand as follows. Suppose $\sigma$ is a strand, composed of edges $e_1, \ldots, e_m$. Set
$$t(\sigma)=\min \left(1, t\left(e_1\right)+\ldots+t\left(e_m\right)\right) .$$
In the above construction, the point $u$ depends only on the numbers $t(\sigma)$ assigned to the strands. Here is another description of the construction of $u$. For each strand $\sigma$ there are indices $i(\sigma)$ and $j(\sigma)$, representing the indices corresponding to the left and right sides of the edges in the strand, respectively. If the strand $\sigma$ contains an edge ending in a vertex $v_{j k}$, then $i(\sigma)=i_{j, k-1}$ and $j(\sigma)=i_{j, k}$. (The notation $i(e)$ and $j(e)$ will also be used for an edge $e$.) Realize the tree geometrically, with a strand $\sigma$ represented by a line segment of length 1. Let $T$ denote the geometric realization of the tree. Then the function $t$ from the set of strands into $[0,1]$, and the initial point $z$, determine a map $\Psi_{z, t}: T \rightarrow Z$. Write $z=\left(z_1, \ldots, z_n\right)$. The top vertices of the tree go to the points $z_k \in Z$. The left and right side strands are mapped to $P$ and $Q$ respectively. If $\sigma$ is any strand, $\Psi_{z, t}$ maps the segment corresponding to $\sigma$ into $Z$ using the flow $f_{i(\sigma) j(\sigma)}$, beginning with the point corresponding to the fork $v$ at the top of $\sigma$, and moving at speed $t(\sigma)$. The beginning point $\Psi_{z, t}(v)$ has already been constructed inductively. If $p$ is a point on the segment $\sigma$, at distance $y$ below the fork $v, \Psi_{z, t}(p)=f_{i(\sigma) j(\sigma)}\left(\Psi_{z, t}(v), t(\sigma) y\right)$. Finally, the the values of $\Psi_{z, t}$ on the $n+r$ bottom vertices provide the points $u_1, \ldots, u_{n+r}$ to determine $u=u(z, t) \in Z_{I_r}$.

# 黎曼曲面代考

## 数学代写|黎曼曲面代写Riemann surface代考|THE MAIN LEMMA

$$\varphi=\sum_r(A K)^r \eta \tau=\sum_r(-K A)^r H \varphi \psi=\sum_r(-K A)^r K \nu$$

$$F K_{k_r} \alpha_r \ldots K_{k_1} \alpha_1 z$$

## 数学代写|黎曼曲面代写Riemann surface代考|THE MAIN LEMMA

$$t(\sigma)=\min \left(1, t\left(e_1\right)+\ldots+t\left(e_m\right)\right) .$$

## 有限元方法代写

tatistics-lab作为专业的留学生服务机构，多年来已为美国、英国、加拿大、澳洲等留学热门地的学生提供专业的学术服务，包括但不限于Essay代写，Assignment代写，Dissertation代写，Report代写，小组作业代写，Proposal代写，Paper代写，Presentation代写，计算机作业代写，论文修改和润色，网课代做，exam代考等等。写作范围涵盖高中，本科，研究生等海外留学全阶段，辐射金融，经济学，会计学，审计学，管理学等全球99%专业科目。写作团队既有专业英语母语作者，也有海外名校硕博留学生，每位写作老师都拥有过硬的语言能力，专业的学科背景和学术写作经验。我们承诺100%原创，100%专业，100%准时，100%满意。

## MATLAB代写

MATLAB 是一种用于技术计算的高性能语言。它将计算、可视化和编程集成在一个易于使用的环境中，其中问题和解决方案以熟悉的数学符号表示。典型用途包括：数学和计算算法开发建模、仿真和原型制作数据分析、探索和可视化科学和工程图形应用程序开发，包括图形用户界面构建MATLAB 是一个交互式系统，其基本数据元素是一个不需要维度的数组。这使您可以解决许多技术计算问题，尤其是那些具有矩阵和向量公式的问题，而只需用 C 或 Fortran 等标量非交互式语言编写程序所需的时间的一小部分。MATLAB 名称代表矩阵实验室。MATLAB 最初的编写目的是提供对由 LINPACK 和 EISPACK 项目开发的矩阵软件的轻松访问，这两个项目共同代表了矩阵计算软件的最新技术。MATLAB 经过多年的发展，得到了许多用户的投入。在大学环境中，它是数学、工程和科学入门和高级课程的标准教学工具。在工业领域，MATLAB 是高效研究、开发和分析的首选工具。MATLAB 具有一系列称为工具箱的特定于应用程序的解决方案。对于大多数 MATLAB 用户来说非常重要，工具箱允许您学习应用专业技术。工具箱是 MATLAB 函数（M 文件）的综合集合，可扩展 MATLAB 环境以解决特定类别的问题。可用工具箱的领域包括信号处理、控制系统、神经网络、模糊逻辑、小波、仿真等。

## 数学代写|黎曼曲面代写Riemann surface代考|MATH3405

statistics-lab™ 为您的留学生涯保驾护航 在代写黎曼曲面Riemann surface方面已经树立了自己的口碑, 保证靠谱, 高质且原创的统计Statistics代写服务。我们的专家在代写黎曼曲面Riemann surface代写方面经验极为丰富，各种代写黎曼曲面Riemann surface相关的作业也就用不着说。

• Statistical Inference 统计推断
• Statistical Computing 统计计算
• (Generalized) Linear Models 广义线性模型
• Statistical Machine Learning 统计机器学习
• Longitudinal Data Analysis 纵向数据分析
• Foundations of Data Science 数据科学基础

## 数学代写|黎曼曲面代写Riemann surface代考|CONSTRUCTION OF FLOWS

In this section we construct some flows on the one dimensional manifold $Z$. These will be used in following sections to move relative homology cycles. We will take some care in the construction of the flows, to obtain technically useful properties.

Suppose that $g$ is a holomorphic function on $Z$, such as one of the functions $g_{i j}(z)=g_i(z)-g_j(z)$. We want to construct a flow $f(z, t)$ with the property that $f(z, 0)=z$, and $g(f(z, t))$ is “downwind” of $g(z)$ in a certain desired direction. In other words, the time derivative of $g(f(z, t))$ is contained in an angular sector of the form
$$S(\pm \delta) \stackrel{\text { def }}{=}\left{r e^{i \theta}: \theta \in[\pi-\delta, \pi+\delta]\right}$$
so $g(f(z, t))$ is contained in an angular sector of the form
$$S(g(z), \pm \delta) \stackrel{\text { def }}{=}\left{g(z)+r e^{i \theta}: \theta \in[\pi-\delta, \pi+\delta]\right} .$$
We would also like to insure that at $t=1$, the flow has the effect of moving $g(f(z, t))$ a certain distance away from $g(z)$. This will be possible unless critical points of $g$ are encountered first. We require some special behaviour as the flow moves past critical points. There will be a one dimensional subset $\Lambda \subset \mathrm{C}$, the union of paths which are approximately paths of steepest descent leading away from critical points of $g$. The flow $f$ will have the effect of moving points to $\Lambda$, and then along $\Lambda$ away from the critical points.

Recall that we are admitting the possibility of rotating the $t$ or $\zeta$ planes. This is the same as multiplying the function $g$ by $e^{i \theta}$. After making such a rotation, we can assume that the desired direction of flow is in the negative real direction. Note that $g(P)=0$ for any of the functions $g_{i j}$ considered. Thus rotation preserves $g(P)$.

Our construction of flows will make reference to four numbers, a choice of angular error $\delta$, a choice of small number $\sigma$, a choice of number $L$, and a choice of radius $R$. The number $L$ represents the minimum amount by which the real part of $g$ should be decreased by the flow, unless a critical point is encountered. The angular error represents the maximum allowed deviation from the negative real direction, for the direction in which $g(z)$ moves when $z$ is moved by the flow. The $\sigma$ is a small number which indicates what happens when the flow goes past a critical point.

## 数学代写|黎曼曲面代写Riemann surface代考|MOVING RELATIVE HOMOLOGY CHAINS

In this section we will describe a formalism for moving relative homology chains. We will form a double complex to calculate relative homology, and then consider homotopies in this complex. It will be done explicitly, so as to facilitate getting bounds.
$Z$ is a complex manifold of dimension one, the universal cover of the original Riemann surface $S$. We consider indices $I=\left(i_0, \ldots, i_n\right)$, saying $|I|=n$. For each such index let $Z_I$ be the space $Z^n$. Let
$$Z_n=\coprod_{|I|=n} Z_I, \quad Z_*=\coprod_I Z_I .$$
We will work with chains which are combinations of singular and de Rham chains. Our manifolds will have linear structures, in other words embeddings as open sets in vector spaces. By a $k$-chain on such a manifold $Y$ we will mean a linear functional on the space of $C^{\infty}$ differential $k$-forms on $Y$ which can be expressed as a sum of components of the following form $h(u * H)$. Here $H$ is a $k+l$ dimensional space, compact, with linear structure and algebraic boundary, together with $h: H \rightarrow Y$ a smooth algebraic map (in other words the map is given by coordinate functions which are algebraic over the ring of polynomial functions on $H$ ). It is contracted with a smooth differential $l$-form $u$ on $H$. Such a chain provides a linear functional on the space of $k$-forms $a$ by the rule
$$\langle h(u * H), a\rangle=\int_H u \wedge h^*(a) .$$
The reader may think primarily of singular chains (corresponding to the case when $u$ is just the function 1). The more general singular-de Rham chains arise because we use cutoff functions later in the argument. Still, we usually denote $\langle\eta, a\rangle$ by $\int_\eta a$.

These algebraic singular-de Rham chains are functorial with respect to continuous piecewise polynomial maps (even though more general types of currents are not). Suppose $f: Y \rightarrow Y^{\prime}$ is continuous and piecewise polynomial, and suppose $h(u * H)$ is a $k$-chain on $Y$. The composition $f h: H \rightarrow Y^{\prime}$ is continuous and piecewise polynomial. We may further subdivide $H$ into finitely many pieces $H_i$ (with algebraic boundaries) such that on each $H_i, f h$ is polynomial. Let $u_i$ be the restriction of $u$ to $H_i$. Then define
$$f(h(u * H))=\sum(f h)\left(u_i * H_i\right)$$

# 黎曼曲面代考

## 数学代写|黎曼曲面代写Riemann surface代考|MOVING RELATIVE HOMOLOGY CHAINS

$Z$ 是一维复流形，原黎曼曲面的普覆盖 $S$. 我们考虑指数 $I=\left(i_0, \ldots, i_n\right)$ ，说 $|I|=n$. 对于每个这样的 索引让 $Z_I$ 成为空间 $Z^n$. 让
$$Z_n=\coprod_{|I|=n} Z_I, \quad Z_*=\coprod_I Z_I$$

$$\langle h(u * H), a\rangle=\int_H u \wedge h^*(a) .$$

$$f(h(u * H))=\sum(f h)\left(u_i * H_i\right)$$

## 有限元方法代写

tatistics-lab作为专业的留学生服务机构，多年来已为美国、英国、加拿大、澳洲等留学热门地的学生提供专业的学术服务，包括但不限于Essay代写，Assignment代写，Dissertation代写，Report代写，小组作业代写，Proposal代写，Paper代写，Presentation代写，计算机作业代写，论文修改和润色，网课代做，exam代考等等。写作范围涵盖高中，本科，研究生等海外留学全阶段，辐射金融，经济学，会计学，审计学，管理学等全球99%专业科目。写作团队既有专业英语母语作者，也有海外名校硕博留学生，每位写作老师都拥有过硬的语言能力，专业的学科背景和学术写作经验。我们承诺100%原创，100%专业，100%准时，100%满意。

## MATLAB代写

MATLAB 是一种用于技术计算的高性能语言。它将计算、可视化和编程集成在一个易于使用的环境中，其中问题和解决方案以熟悉的数学符号表示。典型用途包括：数学和计算算法开发建模、仿真和原型制作数据分析、探索和可视化科学和工程图形应用程序开发，包括图形用户界面构建MATLAB 是一个交互式系统，其基本数据元素是一个不需要维度的数组。这使您可以解决许多技术计算问题，尤其是那些具有矩阵和向量公式的问题，而只需用 C 或 Fortran 等标量非交互式语言编写程序所需的时间的一小部分。MATLAB 名称代表矩阵实验室。MATLAB 最初的编写目的是提供对由 LINPACK 和 EISPACK 项目开发的矩阵软件的轻松访问，这两个项目共同代表了矩阵计算软件的最新技术。MATLAB 经过多年的发展，得到了许多用户的投入。在大学环境中，它是数学、工程和科学入门和高级课程的标准教学工具。在工业领域，MATLAB 是高效研究、开发和分析的首选工具。MATLAB 具有一系列称为工具箱的特定于应用程序的解决方案。对于大多数 MATLAB 用户来说非常重要，工具箱允许您学习应用专业技术。工具箱是 MATLAB 函数（M 文件）的综合集合，可扩展 MATLAB 环境以解决特定类别的问题。可用工具箱的领域包括信号处理、控制系统、神经网络、模糊逻辑、小波、仿真等。

## 数学代写|黎曼曲面代写Riemann surface代考|KMA152

statistics-lab™ 为您的留学生涯保驾护航 在代写黎曼曲面Riemann surface方面已经树立了自己的口碑, 保证靠谱, 高质且原创的统计Statistics代写服务。我们的专家在代写黎曼曲面Riemann surface代写方面经验极为丰富，各种代写黎曼曲面Riemann surface相关的作业也就用不着说。

• Statistical Inference 统计推断
• Statistical Computing 统计计算
• (Generalized) Linear Models 广义线性模型
• Statistical Machine Learning 统计机器学习
• Longitudinal Data Analysis 纵向数据分析
• Foundations of Data Science 数据科学基础

## 数学代写|黎曼曲面代写Riemann surface代考|ORDINARY DIFFERENTIAL EQUATIONS ON A PdEMANN SURFACE

Let $S$ be a compact Riemann surface. We will consider systems of first order ordinary differential equations on $S$
$$(d-t A-B) m=0$$
where $A$ and $B$ are $k \times k$ matrices of holomorphic one-forms on $S, t$ is a complex parameter, and $m$ is a column vector or $k \times k$ matrix of functions. We make the following assumption:
$A$ is a diagonal matrix with one-forms $a_1, \ldots, a_k$ along the diagonal. The diagonal entries of $B$ are equal to zero.

The solutions of the system of differential equations are multivalued holomorphic functions on $S$, so it is more convenient to introduce the universal cover $Z=\tilde{S}$. This is complex analytically equivalent to a domain in the complex plane, and it is sometimes useful to keep such an embedding in mind.

Fix a base point $P$ in $Z$ (lying above a base point which we also denote by $P$ in $S$ ). There is a unique matrix valued solution $m(z)$ defined for $z \in Z$, specified by initial conditions $m(P)=I$. For any point $Q$ on $Z$, the value $m(Q)$ is well defined. It depends on the parameter $t$, so we obtain an entire matrix valued function $m(t)=m(Q, t)$ of the complex variable $t$.

Our aim is to investigate the behavior of $m(t)$ as $t \rightarrow \infty$. We can state a theorem which is essentially the main result. Restrict to positive real values of t. Recall that an asymptotic expansion for $m(t)$ is an expression
$$m(t) \sim \sum_{i=1}^{\Gamma} \sum_{j=J}^{\infty} \sum_{k=0}^{K(j)} c_{i j k} e^{\lambda_i t} t^{-\frac{1}{N}}(\log t)^k$$
where the real parts of the exponents are equal-say $\Re \lambda_i=\xi$ for all $i$, such that for each $M$ there is a $y(M)$ and a constant $C(M)$ such that for $t \geq y(M)$,
$$\left|m(t)-\sum_{i=1}^r \sum_{j=J}^{N M} \sum_{k=0}^{K(j)} c_{i j k} e^{\lambda, t} t^{-\frac{1}{N}}(\log t)^k\right| \leq C(M) e^{\xi t} t^{-M} .$$
Call the numbers $\lambda_i$ the complex exponents of the expansion, and the number $\xi$ the real exponent or just the exponent.

## 数学代写|黎曼曲面代写Riemann surface代考|LAPLACE TRANSFORM, ASYMPTOTIC EXPANSIONS

Classically, the method of the stationary phase (or steepest descent) provided asymptotic expansions for integrals such as
$$\int f(z) e^{-t x^2} d z .$$
In this paper we are interested in obtaining asymptotic expansions for more general integrals such as
$$m(t)=\int_\eta b e^{t g},$$
where $g$ is a holomorphic function on a complex manifold, $b$ is a holomorphic differential form of top degree, and $\eta$ is a cycle in homology or relative homology (of real dimension equal to the complex dimension of the manifold). Instead of applying the method of stationary phase directly to such an integral, it will be more useful to take the Laplace transform first. The Laplace transform keeps lower order information which is lost upon going to the asymptotic expansion. If several such integrals are added together and their asymptotic expansions cancel, then an asymptotic expansion at lower exponent can be recovered from the sum of the Laplace transforms.

Suppose that $m(t)$ is an entire holomorphic function of order $\leq 1$. This means that there is a bound
$$|m(t)| \leq C e^{a|t|} .$$
The Laplace transform of $m$ is defined to be the integral
$$f(\zeta)=\int_0^{\infty} m(t) e^{-\zeta t} d t .$$
The integration is taken along a direction in which the integrand is rapidly decreasing. $f(\zeta)$ is defined and holomorphic for $|\zeta|>a$, and it vanishes at $\infty$. Conversely the function $m(t)$ can be recovered as the inverse Laplace transform
$$m(t)=\frac{1}{2 \pi i} \oint f(\zeta) e^{\zeta t} d \zeta .$$
Here the path of integration is a large circle running once counterclockwise around the annulus $|\zeta|>a$.

# 黎曼曲面代考

## 数学代写|黎曼曲面代写Riemann surface代考|ORDINARY DIFFERENTIAL EQUATIONS ON A PdEMANN SURFACE

$$(d-t A-B) m=0$$

$A$ 是具有一种形式的对角矩阵 $a_1, \ldots, a_k$ 沿着对角线。的对角线条目 $B$ 等于零。

$$m(t) \sim \sum_{i=1}^{\Gamma} \sum_{j=J}^{\infty} \sum_{k=0}^{K(j)} c_{i j k} e^{\lambda_i t} t^{-\frac{1}{N}}(\log t)^k$$

$$\left|m(t)-\sum_{i=1}^r \sum_{j=J}^{N M} \sum_{k=0}^{K(j)} c_{i j k} e^{\lambda, t} t^{-\frac{1}{N}}(\log t)^k\right| \leq C(M) e^{\xi t} t^{-M}$$

## 数学代写|黎曼曲面代写Riemann surface代考|LAPLACE TRANSFORM, ASYMPTOTIC EXPANSIONS

$$\int f(z) e^{-t x^2} d z$$

$$m(t)=\int_\eta b e^{t g},$$

$$|m(t)| \leq C e^{a|t|} .$$

$$f(\zeta)=\int_0^{\infty} m(t) e^{-\zeta t} d t$$

$$m(t)=\frac{1}{2 \pi i} \oint f(\zeta) e^{\zeta t} d \zeta .$$

## 有限元方法代写

tatistics-lab作为专业的留学生服务机构，多年来已为美国、英国、加拿大、澳洲等留学热门地的学生提供专业的学术服务，包括但不限于Essay代写，Assignment代写，Dissertation代写，Report代写，小组作业代写，Proposal代写，Paper代写，Presentation代写，计算机作业代写，论文修改和润色，网课代做，exam代考等等。写作范围涵盖高中，本科，研究生等海外留学全阶段，辐射金融，经济学，会计学，审计学，管理学等全球99%专业科目。写作团队既有专业英语母语作者，也有海外名校硕博留学生，每位写作老师都拥有过硬的语言能力，专业的学科背景和学术写作经验。我们承诺100%原创，100%专业，100%准时，100%满意。

## MATLAB代写

MATLAB 是一种用于技术计算的高性能语言。它将计算、可视化和编程集成在一个易于使用的环境中，其中问题和解决方案以熟悉的数学符号表示。典型用途包括：数学和计算算法开发建模、仿真和原型制作数据分析、探索和可视化科学和工程图形应用程序开发，包括图形用户界面构建MATLAB 是一个交互式系统，其基本数据元素是一个不需要维度的数组。这使您可以解决许多技术计算问题，尤其是那些具有矩阵和向量公式的问题，而只需用 C 或 Fortran 等标量非交互式语言编写程序所需的时间的一小部分。MATLAB 名称代表矩阵实验室。MATLAB 最初的编写目的是提供对由 LINPACK 和 EISPACK 项目开发的矩阵软件的轻松访问，这两个项目共同代表了矩阵计算软件的最新技术。MATLAB 经过多年的发展，得到了许多用户的投入。在大学环境中，它是数学、工程和科学入门和高级课程的标准教学工具。在工业领域，MATLAB 是高效研究、开发和分析的首选工具。MATLAB 具有一系列称为工具箱的特定于应用程序的解决方案。对于大多数 MATLAB 用户来说非常重要，工具箱允许您学习应用专业技术。工具箱是 MATLAB 函数（M 文件）的综合集合，可扩展 MATLAB 环境以解决特定类别的问题。可用工具箱的领域包括信号处理、控制系统、神经网络、模糊逻辑、小波、仿真等。

## 数学代写|黎曼几何代写Riemannian geometry代考|KMA152

statistics-lab™ 为您的留学生涯保驾护航 在代写黎曼几何Riemannian geometry方面已经树立了自己的口碑, 保证靠谱, 高质且原创的统计Statistics代写服务。我们的专家在代写黎曼几何Riemannian geometry代写方面经验极为丰富，各种代写黎曼几何Riemannian geometry相关的作业也就用不着说。

• Statistical Inference 统计推断
• Statistical Computing 统计计算
• (Generalized) Linear Models 广义线性模型
• Statistical Machine Learning 统计机器学习
• Longitudinal Data Analysis 纵向数据分析
• Foundations of Data Science 数据科学基础

## 数学代写|黎曼几何代写Riemannian geometry代考|Gauss–Bonnet Theorem: Global Version

Now we state the global version of the Gauss-Bonnet theorem. In other words we want to generalize (1.33) to the case when $\Gamma$ is a region of $M$ that is not necessarily homeomorphic to a disk; see for instance Figure 1.4. As we will find, the result depends on the Euler characteristic $\chi(\Gamma)$ of this region.

In what follows, by a triangulation of $M$ we mean a decomposition of $M$ into curvilinear polygons (see Definition 1.31). Notice that every compact surface admits a triangulation. ${ }^{3}$

Definition $1.34$ Let $M \subset \mathbb{R}^{3}$ be a compact oriented surface with piecewise smooth boundary $\partial M$. Consider a triangulation of $M$. We define the Euler characteristic of $M$ as
$$\chi(M):=n_{2}-n_{1}+n_{0},$$
where $n_{i}$ is the number of $i$-dimensional faces in the triangulation.
The Euler characteristic can be defined for every region $\Gamma$ of $M$ in the same way. Here, by a region $\Gamma$ on a surface $M$ we mean a closed domain of the manifold with piecewise smooth boundary.

## 数学代写|黎曼几何代写Riemannian geometry代考|Consequences of the Gauss–Bonnet Theorems

Definition $1.39$ Let $M, M^{\prime}$ be two surfaces in $\mathbb{R}^{3}$. A smooth map $\phi: \mathbb{R}^{3} \rightarrow$ $\mathbb{R}^{3}$ is called a local isometry between $M$ and $M^{\prime}$ if $\phi(M)=M^{\prime}$ and for every $q \in M$ it satisfies
$$\langle v \mid w\rangle=\left\langle D_{q} \phi(v) \mid D_{q} \phi(w)\right\rangle, \quad \forall v, w \in T_{q} M .$$
If, moreover, the map $\phi$ is a bijection then $\phi$ is called a global isometry. Two surfaces $M$ and $M^{\prime}$ are said to be locally isometric (resp. globally isometric) if there exists a local isometry (resp. global isometry) between $M$ and $M^{\prime}$. Notice that the restriction $\phi$ of an isometry of $\mathbb{R}^{3}$ to a surface $M \subset \mathbb{R}^{3}$ always defines a global isometry between $M$ and $M^{\prime}=\phi(M)$.

Formula (1.52) says that a local isometry between two surfaces $M$ and $M^{\prime}$ preserves the angles between tangent vectors and, a fortiori, the lengths of curves and the distances between points.

By Corollary 1.33, thanks to the fact that the angles and the volumes are preserved by isometries, one obtains that the Gaussian curvature is invariant under local isometries, in the following sense.

Theorem $1.40$ (Gauss’ theorema egregium) Let $\phi$ be a local isometry between $M$ and $M^{\prime}$. Then for every $q \in M$ one has $\kappa(q)=\kappa^{\prime}(\phi(q))$, where $\kappa$ (resp. $\kappa^{\prime}$ ) is the Gaussian curvature of $M$ (resp. $M^{\prime}$ ).

This result says that the Gaussian curvature $\kappa$ depends only on the metric structure on $M$ and not on the specific fact that the surface is embedded in $\mathbb{R}^{3}$ with the induced inner product.

## 数学代写|黎曼几何代写Riemannian geometry代考|Gauss–Bonnet Theorem: Global Version

$$\chi(M):=n_{2}-n_{1}+n_{0}$$

## 数学代写|黎曼几何代写Riemannian geometry代考|Consequences of the Gauss–Bonnet Theorems

$$\langle v \mid w\rangle=\left\langle D_{q} \phi(v) \mid D_{q} \phi(w)\right\rangle, \quad \forall v, w \in T_{q} M .$$

## 有限元方法代写

tatistics-lab作为专业的留学生服务机构，多年来已为美国、英国、加拿大、澳洲等留学热门地的学生提供专业的学术服务，包括但不限于Essay代写，Assignment代写，Dissertation代写，Report代写，小组作业代写，Proposal代写，Paper代写，Presentation代写，计算机作业代写，论文修改和润色，网课代做，exam代考等等。写作范围涵盖高中，本科，研究生等海外留学全阶段，辐射金融，经济学，会计学，审计学，管理学等全球99%专业科目。写作团队既有专业英语母语作者，也有海外名校硕博留学生，每位写作老师都拥有过硬的语言能力，专业的学科背景和学术写作经验。我们承诺100%原创，100%专业，100%准时，100%满意。

## MATLAB代写

MATLAB 是一种用于技术计算的高性能语言。它将计算、可视化和编程集成在一个易于使用的环境中，其中问题和解决方案以熟悉的数学符号表示。典型用途包括：数学和计算算法开发建模、仿真和原型制作数据分析、探索和可视化科学和工程图形应用程序开发，包括图形用户界面构建MATLAB 是一个交互式系统，其基本数据元素是一个不需要维度的数组。这使您可以解决许多技术计算问题，尤其是那些具有矩阵和向量公式的问题，而只需用 C 或 Fortran 等标量非交互式语言编写程序所需的时间的一小部分。MATLAB 名称代表矩阵实验室。MATLAB 最初的编写目的是提供对由 LINPACK 和 EISPACK 项目开发的矩阵软件的轻松访问，这两个项目共同代表了矩阵计算软件的最新技术。MATLAB 经过多年的发展，得到了许多用户的投入。在大学环境中，它是数学、工程和科学入门和高级课程的标准教学工具。在工业领域，MATLAB 是高效研究、开发和分析的首选工具。MATLAB 具有一系列称为工具箱的特定于应用程序的解决方案。对于大多数 MATLAB 用户来说非常重要，工具箱允许您学习应用专业技术。工具箱是 MATLAB 函数（M 文件）的综合集合，可扩展 MATLAB 环境以解决特定类别的问题。可用工具箱的领域包括信号处理、控制系统、神经网络、模糊逻辑、小波、仿真等。

## 数学代写|黎曼几何代写Riemannian geometry代考|MTH3022

statistics-lab™ 为您的留学生涯保驾护航 在代写黎曼几何Riemannian geometry方面已经树立了自己的口碑, 保证靠谱, 高质且原创的统计Statistics代写服务。我们的专家在代写黎曼几何Riemannian geometry代写方面经验极为丰富，各种代写黎曼几何Riemannian geometry相关的作业也就用不着说。

• Statistical Inference 统计推断
• Statistical Computing 统计计算
• (Generalized) Linear Models 广义线性模型
• Statistical Machine Learning 统计机器学习
• Longitudinal Data Analysis 纵向数据分析
• Foundations of Data Science 数据科学基础

## 数学代写|黎曼几何代写Riemannian geometry代考|Gauss–Bonnet Theorems

In this section we will prove both the local and the global version of the GaussBonnet theorem. A strong consequence of these results is the celebrated Gauss’ theorema egregium, which says that the Gaussian curvature of a surface is independent of its embedding in $\mathbb{R}^{3}$.

Definition $1.29$ Let $\gamma:[0, T] \rightarrow M$ be a smooth curve parametrized by arclength. The geodesic curvature of $\gamma$ is defined as
$$\rho_{\gamma}(t)=\omega_{\dot{\gamma}(t)}(\ddot{\gamma}(t))$$
Nótice that if $\gamma$ is a géodésic, thên $\rho_{\gamma}(t)=0$ fố everry $t \in[0, T]$. Thé geodesic curvature measures how far a curve is from being a geodesic.

Remark $1.30$ The geodesic curvature changes sign if we move along the curve in the opposite direction. Moreover, if $M=\mathbb{R}^{2}$, it coincides with the usual notion of the curvature of a planar curve.

## 数学代写|黎曼几何代写Riemannian geometry代考|Gauss–Bonnet Theorem: Local Version

A regular polygon in $\mathbb{R}^{2}$ is a polygon that is equiangular and equilateral. We include disks among regular polygons (as a limiting case, when the number of edges is infinite).

Definition 1.31 A curvilinear polygon $\Gamma$ on an oriented surface $M$ is the image of a regular polygon in $\mathbb{R}^{2}$ under a diffeomorphism. We assume that $\partial \Gamma$ is oriented consistently with the orientation of $M$.

Notice that a curvilinear polygon is always homeomorphic to a disk, and the case when $\partial \Gamma$ is smooth (and $\Gamma$ is diffeomorphic to the disk) is included in the definition.

In what follows, given a curvilinear polygon $\Gamma$ on an oriented surface $M$ (see Figure 1.2), we denote by

• $\gamma_{i}: I_{i} \rightarrow M$, for $i=1, \ldots, m$, the smooth curves parametrized by arc length, with orientation consistent with $\partial \Gamma$, such that $\partial \Gamma=\cup_{i=1}^{m} \gamma_{i}\left(I_{i}\right)$,
• $\alpha_{i}$, for $i=1, \ldots, m$, the external angles at the points where $\partial \Gamma$ is not $C^{1}$.
Theorem 1.32 (Gauss-Bonnet, local version) Let $\Gamma$ be a curvilinear polygon on an oriented surface $M$. Then we have
$$\int_{\Gamma} \kappa d V+\sum_{i=1}^{m} \int_{I_{i}} \rho_{\gamma_{i}}(t) d t+\sum_{i=1}^{m} \alpha_{i}=2 \pi$$
Proof (a) The case where $\partial \Gamma$ is smooth. In this case $\Gamma$ is the image of the unit (closed) ball $B_{1}$, centered at the origin of $\mathbb{R}^{2}$, under a diffeomorphism
$$F: B_{1} \rightarrow M . \quad \Gamma=F\left(B_{1}\right) .$$
In what follows we denote by $\gamma: I \rightarrow M$ the curve such that $\gamma(I)=\partial \Gamma$. We consider on $B_{1}$ the vector field $V(x)=x_{1} \partial_{x_{2}}-x_{2} \partial_{x_{1}}$ which has an isolated zero at the origin and whose flow is a rotation around zero. Denote by $X:=F_{*} V$ the induced vector field on $M$ with critical point $q_{0}=F(0)$.

## 数学代写|黎曼几何代写Riemannian geometry代考|Gauss–Bonnet Theorems

$$\rho_{\gamma}(t)=\omega_{\dot{\gamma}(t)}(\ddot{\gamma}(t))$$

## 数学代写|黎曼几何代写Riemannian geometry代考|Gauss–Bonnet Theorem: Local Version

• $\gamma_{i}: I_{i} \rightarrow M$ ，为了 $i=1, \ldots, m$, 由弧长参数化的平滑曲线，方向与 $\partial \Gamma$, 这样 $\partial \Gamma=\cup_{i=1}^{m} \gamma_{i}\left(I_{i}\right)$,
定理 $1.32$ (Gauss-Bonnet，本地版本) 让 $\Gamma$ 是有向曲面上的曲线多边形 $M$. 然后我们有
$$\int_{\Gamma} \kappa d V+\sum_{i=1}^{m} \int_{I_{i}} \rho_{\gamma_{i}}(t) d t+\sum_{i=1}^{m} \alpha_{i}=2 \pi$$
证明 (a) 情况 $\partial \Gamma$ 是光滑的。在这种情况下 $\Gamma$ 是单位（封闭) 球的形象 $B_{1}$ ，以原点为中心 $\mathbb{R}^{2}$ ，在微分同胚下
$$F: B_{1} \rightarrow M . \quad \Gamma=F\left(B_{1}\right) .$$
下面我们用 $\gamma: I \rightarrow M$ 曲线使得 $\gamma(I)=\partial \Gamma$. 我们考虑 $B_{1}$ 向量场 $V(x)=x_{1} \partial_{x_{2}}-x_{2} \partial_{x_{1}}$ 它在原点有一个 孤立的零，其流动是围绕零旋转。表示为 $X:=F_{*} V$ 上的诱导矢量场 $M$ 有临界点 $q_{0}=F(0)$.

## 有限元方法代写

tatistics-lab作为专业的留学生服务机构，多年来已为美国、英国、加拿大、澳洲等留学热门地的学生提供专业的学术服务，包括但不限于Essay代写，Assignment代写，Dissertation代写，Report代写，小组作业代写，Proposal代写，Paper代写，Presentation代写，计算机作业代写，论文修改和润色，网课代做，exam代考等等。写作范围涵盖高中，本科，研究生等海外留学全阶段，辐射金融，经济学，会计学，审计学，管理学等全球99%专业科目。写作团队既有专业英语母语作者，也有海外名校硕博留学生，每位写作老师都拥有过硬的语言能力，专业的学科背景和学术写作经验。我们承诺100%原创，100%专业，100%准时，100%满意。

## MATLAB代写

MATLAB 是一种用于技术计算的高性能语言。它将计算、可视化和编程集成在一个易于使用的环境中，其中问题和解决方案以熟悉的数学符号表示。典型用途包括：数学和计算算法开发建模、仿真和原型制作数据分析、探索和可视化科学和工程图形应用程序开发，包括图形用户界面构建MATLAB 是一个交互式系统，其基本数据元素是一个不需要维度的数组。这使您可以解决许多技术计算问题，尤其是那些具有矩阵和向量公式的问题，而只需用 C 或 Fortran 等标量非交互式语言编写程序所需的时间的一小部分。MATLAB 名称代表矩阵实验室。MATLAB 最初的编写目的是提供对由 LINPACK 和 EISPACK 项目开发的矩阵软件的轻松访问，这两个项目共同代表了矩阵计算软件的最新技术。MATLAB 经过多年的发展，得到了许多用户的投入。在大学环境中，它是数学、工程和科学入门和高级课程的标准教学工具。在工业领域，MATLAB 是高效研究、开发和分析的首选工具。MATLAB 具有一系列称为工具箱的特定于应用程序的解决方案。对于大多数 MATLAB 用户来说非常重要，工具箱允许您学习应用专业技术。工具箱是 MATLAB 函数（M 文件）的综合集合，可扩展 MATLAB 环境以解决特定类别的问题。可用工具箱的领域包括信号处理、控制系统、神经网络、模糊逻辑、小波、仿真等。

## 数学代写|黎曼几何代写Riemannian geometry代考|MAST90029

statistics-lab™ 为您的留学生涯保驾护航 在代写黎曼几何Riemannian geometry方面已经树立了自己的口碑, 保证靠谱, 高质且原创的统计Statistics代写服务。我们的专家在代写黎曼几何Riemannian geometry代写方面经验极为丰富，各种代写黎曼几何Riemannian geometry相关的作业也就用不着说。

• Statistical Inference 统计推断
• Statistical Computing 统计计算
• (Generalized) Linear Models 广义线性模型
• Statistical Machine Learning 统计机器学习
• Longitudinal Data Analysis 纵向数据分析
• Foundations of Data Science 数据科学基础

## 数学代写|黎曼几何代写Riemannian geometry代考|Parallel Transport

In this section we want to introduce the notion of parallel transport on a surface (along a curve), which allows us to define its main geometric invariant: the Gaussian curvature.

Definition $1.14$ Let $\gamma:[0, T] \rightarrow M$ be a smooth curve. A smooth curve of tangent vectors $\xi(t) \in T_{\nu(t)} M$ is said to be parallel if $\dot{\xi}(t) \perp T_{\gamma(t)} M$.

This notion generalizes the notion of parallelism of vectors on the plane, where it is possible to canonically identify every tangent space to $M=\mathbb{R}^{2}$ with $\mathbb{R}^{2}$ itself. ${ }^{2}$ In this case a smooth curve of tangent vectors $\xi(t) \in T_{\gamma(t)} M$ is parallel if and only if $\dot{\xi}(t)=0$.

When $M$ is the zero level of a smooth function $a: \mathbb{R}^{3} \rightarrow \mathbb{R}$, as in (1.14), we have the following description:

Proposition $1.15$ A smooth curve of tangent vectors $\xi(t)$ defined along $\gamma:[0, T] \rightarrow M$ is parallel if and only if it satisfies
$$\dot{\xi}(t)=-\frac{\dot{\gamma}(t)^{T}\left(\nabla_{\gamma(t)}^{2} a\right) \xi(t)}{\left|\nabla_{\gamma(t)} a\right|^{2}} \nabla_{\gamma(t)} a, \quad \forall t \in[0, T] .$$
Proof As in Remark 1.7, $\xi(t) \in T_{\gamma(t)} M$ implies that $\left\langle\nabla_{\gamma(t)} a, \xi(t)\right\rangle=0$. Moreover, by assumption, $\dot{\xi}(t)=\alpha(t) \nabla_{\gamma(t)} a$ for some smooth function $\alpha$. With computations analogous to those in the proof of Proposition $1.8$ we get that
$$\dot{\gamma}(t)^{T}\left(\nabla_{\gamma(t)}^{2} a\right) \xi(t)+\alpha(t)\left|\nabla_{\gamma(t)} a\right|^{2}=0,$$
from which the statement follows.

## 数学代写|黎曼几何代写Riemannian geometry代考|Parallel Transport and the Levi-Civita Connection

Definition 1.19 An orientation of a surface $M$ is a smooth map $v: M \rightarrow \mathbb{R}^{3}$, défineed globally on $M$, such that $v(q) \perp T_{q} M$ and $|v(q)|=1$ for every $q \in M$. Notice that if $v$ is an orientation of $M$, then $-v$ also defines an orientation of $M$.

A surface $M$ is oriented if it is given (when this exists) an orientation. On an oriented surface $M$, an orthonormal frame $\left{e_{1}, e_{2}\right}$ of $T_{q} M$ is said to be positively oriented (resp. negatively oriented) if $e_{1} \wedge e_{2}=k v(q)$ with $k>0$ (resp. $k<0$ ).
In the following we assume that $M$ is an oriented surface.
Definition $1.20$ The spherical bundle $S M$ on $M$ is the disjoint union of all unit tangent vectors to $M$ :
$$S M=\bigsqcup_{q \in M} S_{q} M, \quad S_{q} M=\left{v \in T_{q} M,|v|=1\right}$$
The spherical bundle $S M$ can be endowed with the structure of a smooth manifold of dimension 3 , and more precisely of a fiber bundle with base manifold $M$, typical fiber $S^{1}$ and canonical projection
$$\pi: S M \rightarrow M, \quad \pi(v)=q \quad \text { if } v \in T_{q} M$$

Remark $1.21$ Fix a positively oriented local orthonormal frame $\left{e_{1}(q), e_{2}(q)\right}$ on $M$. Since every vector in the fiber $S_{q} M$ has norm 1, we can write every $v \in S_{q} M$ as $v=(\cos \theta) e_{1}(q)+(\sin \theta) e_{2}(q)$ for $\theta \in S^{1}$.

The choice of such an orthonormal frame then induces coordinates $(q, \theta)$ on $S M$. Notice that the choice of a different positively oriented local orthonormal frame $\left{e_{1}^{\prime}(q), e_{2}^{\prime}(q)\right}$ induces coordinates $\left(q^{\prime}, \theta^{\prime}\right)$ on $S M$, where $q^{\prime}=q$ and $\theta^{\prime}=\theta+\phi(q)$ for $\phi \in C^{\infty}(M)$

The orientation of $M$ permits us, once a unit tangent vector is given, to define a canonical orthonormal frame.

## 数学代写|黎曼几何代写Riemannian geometry代考|Parallel Transport

$$\dot{\xi}(t)=-\frac{\dot{\gamma}(t)^{T}\left(\nabla_{\gamma(t)}^{2} a\right) \xi(t)}{\left|\nabla_{\gamma(t)} a\right|^{2}} \nabla_{\gamma(t)} a, \quad \forall t \in[0, T] .$$

$$\dot{\gamma}(t)^{T}\left(\nabla_{\gamma(t)}^{2} a\right) \xi(t)+\alpha(t)\left|\nabla_{\gamma(t)} a\right|^{2}=0,$$

## 数学代写|黎曼几何代写Riemannian geometry代考|Parallel Transport and the Levi-Civita Connection

Uleft{e_{1}, e_{2} \right } } \text { 的 } T _ { q } M \text { 如果 } e _ { 1 } \wedge e _ { 2 } = k v ( q ) \text { 和 } k > 0 \text { (分别。 } k < 0 \text { )。 }

S M=\bigsqcup_{q \in M $} S_{-}{q} M, \backslash q u a d S_{-}{q} M=\backslash \mid e f t\left{v \backslash\right.$ in $T_{-}{q} M,|v|=1 \backslash$ right $}$

$$\pi: S M \rightarrow M, \quad \pi(v)=q \quad \text { if } v \in T_{q} M$$

## 有限元方法代写

tatistics-lab作为专业的留学生服务机构，多年来已为美国、英国、加拿大、澳洲等留学热门地的学生提供专业的学术服务，包括但不限于Essay代写，Assignment代写，Dissertation代写，Report代写，小组作业代写，Proposal代写，Paper代写，Presentation代写，计算机作业代写，论文修改和润色，网课代做，exam代考等等。写作范围涵盖高中，本科，研究生等海外留学全阶段，辐射金融，经济学，会计学，审计学，管理学等全球99%专业科目。写作团队既有专业英语母语作者，也有海外名校硕博留学生，每位写作老师都拥有过硬的语言能力，专业的学科背景和学术写作经验。我们承诺100%原创，100%专业，100%准时，100%满意。

## MATLAB代写

MATLAB 是一种用于技术计算的高性能语言。它将计算、可视化和编程集成在一个易于使用的环境中，其中问题和解决方案以熟悉的数学符号表示。典型用途包括：数学和计算算法开发建模、仿真和原型制作数据分析、探索和可视化科学和工程图形应用程序开发，包括图形用户界面构建MATLAB 是一个交互式系统，其基本数据元素是一个不需要维度的数组。这使您可以解决许多技术计算问题，尤其是那些具有矩阵和向量公式的问题，而只需用 C 或 Fortran 等标量非交互式语言编写程序所需的时间的一小部分。MATLAB 名称代表矩阵实验室。MATLAB 最初的编写目的是提供对由 LINPACK 和 EISPACK 项目开发的矩阵软件的轻松访问，这两个项目共同代表了矩阵计算软件的最新技术。MATLAB 经过多年的发展，得到了许多用户的投入。在大学环境中，它是数学、工程和科学入门和高级课程的标准教学工具。在工业领域，MATLAB 是高效研究、开发和分析的首选工具。MATLAB 具有一系列称为工具箱的特定于应用程序的解决方案。对于大多数 MATLAB 用户来说非常重要，工具箱允许您学习应用专业技术。工具箱是 MATLAB 函数（M 文件）的综合集合，可扩展 MATLAB 环境以解决特定类别的问题。可用工具箱的领域包括信号处理、控制系统、神经网络、模糊逻辑、小波、仿真等。

## 数学代写|黎曼几何代写Riemannian geometry代考|MATH3405

statistics-lab™ 为您的留学生涯保驾护航 在代写黎曼几何Riemannian geometry方面已经树立了自己的口碑, 保证靠谱, 高质且原创的统计Statistics代写服务。我们的专家在代写黎曼几何Riemannian geometry代写方面经验极为丰富，各种代写黎曼几何Riemannian geometry相关的作业也就用不着说。

• Statistical Inference 统计推断
• Statistical Computing 统计计算
• (Generalized) Linear Models 广义线性模型
• Statistical Machine Learning 统计机器学习
• Longitudinal Data Analysis 纵向数据分析
• Foundations of Data Science 数据科学基础

## 数学代写|黎曼几何代写Riemannian geometry代考|Geodesics and Optimality

Let $M \subset \mathbb{R}^{3}$ be a surface and $\gamma:[0, T] \rightarrow M$ be a smooth curve in $M$. The length of $\gamma$ is defined as
$$\ell(\gamma):=\int_{0}^{T}|\dot{\gamma}(t)| d t,$$
where $|v|=\sqrt{\langle v \mid v\rangle}$ denotes the norm of a vector $v$ in $\mathbb{R}^{3}$.
Notice that the definition of length in (1.1) is invariant under reparametrizations of the curve. Indeed, let $\varphi:\left[0, T^{\prime}\right] \rightarrow[0, T]$ be a smooth monotonic function. Define $\gamma_{\varphi}:\left[0, T^{\prime}\right] \rightarrow M$ by $\gamma_{\varphi}:-\gamma \circ \varphi$. Using the change of variables $t=\varphi(s)$, one gets
$$\ell\left(\gamma_{\varphi}\right)=\int_{0}^{T^{\prime}}\left|\dot{\gamma}{\varphi}(s)\right| d s=\int{0}^{T^{\prime}}|\dot{\gamma}(\varphi(s))||\dot{\varphi}(s)| d s=\int_{0}^{T}|\dot{\gamma}(t)| d t=\ell(\gamma) .$$
The definition of length can be extended to piecewise-smooth curves on $M$ by adding the length of every smooth piece of $\gamma$.

When the curve $\gamma$ is parametrized in such a way that $|\dot{\gamma}(t)| \equiv c$ for some $c>0$ we say that $\gamma$ has constant speed. If moreover $c=1$, we say that $\gamma$ is parametrized by arclength (or arclength parametrized).

The distance between two points $p, q \in M$ is the infimum of the lengths of curves that join $p$ to $q$ :
$d(p, q)=\inf {\ell(\gamma) \mid \gamma:[0, T] \rightarrow M$ piecewise-smooth, $\gamma(0)=p, \gamma(T)=q} .$
Now we focus on length-minimizers, i.e., piecewise-smooth curves $\gamma:[0, T]$ $\rightarrow M$ realizing the distance between their endpoints, i.e., satisfying $\ell(\gamma)=$ $d(\gamma(0), \gamma(T))$.

## 数学代写|黎曼几何代写Riemannian geometry代考|Existence and Minimizing Properties of Geodesics

As a direct consequence of Proposition $1.8$ one obtains the following existence and uniqueness theorem for geodesics.

Corollary 1.10 Let $q \in M$ and $v \in T_{q} M$. There exists a unique geodesic $\gamma:[0, \varepsilon] \rightarrow M$, for $\varepsilon>0$ small enough, such that $\gamma(0)=q$ and $\dot{\gamma}(0)=v$.
Proof By Proposition 1.8, geodesics satisfy a second-order ordinary differential equation (ODE), hence they are smooth curves characterized by their initial position and velocity.

To end this section we show that small pieces of geodesics are always global minimizers.

Theorem $1.11$ Let $\gamma:[0, T] \rightarrow M$ be a geodesic. For every $\tau \in[0, T[$ there exists $\varepsilon>0$ such that
(i) $\left.\gamma\right|{[\tau, \tau+\varepsilon]}$ is a minimizer, i.e., $d(\gamma(\tau), \gamma(\tau+\varepsilon))=\ell\left(\left.\gamma\right|{[\tau, \tau+\varepsilon]}\right)$,
(ii) $\left.\gamma\right|_{[\tau, \tau+\varepsilon]}$ is the unique minimizer joining $\gamma(\tau)$ and $\gamma(\tau+\varepsilon)$ in the class of piecewise-smooth curves, up to reparametrization.

Proof Without loss of generality let us assume that $\tau=0$ and that $\gamma$ is arclength parametrized. Consider an arclength parametrized curve $\alpha$ on $M$, such that $\alpha(0)=\gamma(0)$ and $\dot{\alpha}(0) \perp \dot{\gamma}(0)$, and denote by $(t, s) \mapsto x_{s}(t)$ a smooth variation of geodesics such that $x_{0}(t)=\gamma(t)$ and (see also Figure 1.1)
$$x_{s}(0)=\alpha(s), \quad \dot{x}{s}(0) \perp \frac{\partial}{\partial s} \alpha(s) .$$ The map $\psi:(t, s) \mapsto x{s}(t)$ is smooth and is a local diffeomorphism near $(0,0)$. Indeed, we can compute the partial derivatives
$$\left.\frac{\partial \psi}{\partial t}\right|{t=s=0}=\left.\frac{\partial}{\partial t}\right|{t=0} x_{0}(t)=\dot{\gamma}(0),\left.\quad \frac{\partial \psi}{\partial s}\right|{t=s=0}=\left.\frac{\partial}{\partial s}\right|{s=0} x_{s}(0)=\dot{\alpha}(0),$$ and they are linearly independent. Thus $\psi$ maps a neighborhood $U$ of $(0,0)$ to a neighborhood $W$ of $\gamma(0)$. We now consider a function $\phi$ and a vector field $X$ defined on $W$ by
$$\phi: x_{s}(t) \mapsto t, \quad X: x_{s}(t) \mapsto \dot{x}_{s}(t) .$$

## 数学代写|黎曼几何代写Riemannian geometry代考|Geodesics and Optimality

$$\ell(\gamma):=\int_{0}^{T}|\dot{\gamma}(t)| d t$$

$$\ell\left(\gamma_{\varphi}\right)=\int_{0}^{T^{\prime}}|\dot{\gamma} \varphi(s)| d s=\int 0^{T^{\prime}}|\dot{\gamma}(\varphi(s))||\dot{\varphi}(s)| d s=\int_{0}^{T}|\dot{\gamma}(t)| d t=\ell(\gamma) .$$

-algebracaseitisnormaltoimposeacompatibilitycondition $\$ \$$在实流形的情况下是对称的。或者在复杂的情况下，如果我们知道 (,, 是对称的，则该条件可以看作是现实条件。 经典地，我们通常也会想要 ( ， 是非退化的，或者在最好的情况下，是相关的张量 printwise-invertihle，我们倾向 于将此逆称为度量，或者如果我们没有施加对称性，则称为“广义度量”。这导致我们关注以下内容。 统计代写请认准statistics-lab™. statistics-lab™为您的留学生涯保驾护航。 ## 金融工程代写 金融工程是使用数学技术来解决金融问题。金融工程使用计算机科学、统计学、经济学和应用数学领域的工具和知识来解决当前的金融问题，以及设计新的和创新的金融产品。 ## 非参数统计代写 非参数统计指的是一种统计方法，其中不假设数据来自于由少数参数决定的规定模型；这种模型的例子包括正态分布模型和线性回归模型。 ## 广义线性模型代考 广义线性模型（GLM）归属统计学领域，是一种应用灵活的线性回归模型。该模型允许因变量的偏差分布有除了正态分布之外的其它分布。 术语 广义线性模型（GLM）通常是指给定连续和/或分类预测因素的连续响应变量的常规线性回归模型。它包括多元线性回归，以及方差分析和方差分析（仅含固定效应）。 ## 有限元方法代写 有限元方法（FEM）是一种流行的方法，用于数值解决工程和数学建模中出现的微分方程。典型的问题领域包括结构分析、传热、流体流动、质量运输和电磁势等传统领域。 有限元是一种通用的数值方法，用于解决两个或三个空间变量的偏微分方程（即一些边界值问题）。为了解决一个问题，有限元将一个大系统细分为更小、更简单的部分，称为有限元。这是通过在空间维度上的特定空间离散化来实现的，它是通过构建对象的网格来实现的：用于求解的数值域，它有有限数量的点。边界值问题的有限元方法表述最终导致一个代数方程组。该方法在域上对未知函数进行逼近。[1] 然后将模拟这些有限元的简单方程组合成一个更大的方程系统，以模拟整个问题。然后，有限元通过变化微积分使相关的误差函数最小化来逼近一个解决方案。 tatistics-lab作为专业的留学生服务机构，多年来已为美国、英国、加拿大、澳洲等留学热门地的学生提供专业的学术服务，包括但不限于Essay代写，Assignment代写，Dissertation代写，Report代写，小组作业代写，Proposal代写，Paper代写，Presentation代写，计算机作业代写，论文修改和润色，网课代做，exam代考等等。写作范围涵盖高中，本科，研究生等海外留学全阶段，辐射金融，经济学，会计学，审计学，管理学等全球99%专业科目。写作团队既有专业英语母语作者，也有海外名校硕博留学生，每位写作老师都拥有过硬的语言能力，专业的学科背景和学术写作经验。我们承诺100%原创，100%专业，100%准时，100%满意。 ## 随机分析代写 随机微积分是数学的一个分支，对随机过程进行操作。它允许为随机过程的积分定义一个关于随机过程的一致的积分理论。这个领域是由日本数学家伊藤清在第二次世界大战期间创建并开始的。 ## 时间序列分析代写 随机过程，是依赖于参数的一组随机变量的全体，参数通常是时间。 随机变量是随机现象的数量表现，其时间序列是一组按照时间发生先后顺序进行排列的数据点序列。通常一组时间序列的时间间隔为一恒定值（如1秒，5分钟，12小时，7天，1年），因此时间序列可以作为离散时间数据进行分析处理。研究时间序列数据的意义在于现实中，往往需要研究某个事物其随时间发展变化的规律。这就需要通过研究该事物过去发展的历史记录，以得到其自身发展的规律。 ## 回归分析代写 多元回归分析渐进（Multiple Regression Analysis Asymptotics）属于计量经济学领域，主要是一种数学上的统计分析方法，可以分析复杂情况下各影响因素的数学关系，在自然科学、社会和经济学等多个领域内应用广泛。 ## MATLAB代写 MATLAB 是一种用于技术计算的高性能语言。它将计算、可视化和编程集成在一个易于使用的环境中，其中问题和解决方案以熟悉的数学符号表示。典型用途包括：数学和计算算法开发建模、仿真和原型制作数据分析、探索和可视化科学和工程图形应用程序开发，包括图形用户界面构建MATLAB 是一个交互式系统，其基本数据元素是一个不需要维度的数组。这使您可以解决许多技术计算问题，尤其是那些具有矩阵和向量公式的问题，而只需用 C 或 Fortran 等标量非交互式语言编写程序所需的时间的一小部分。MATLAB 名称代表矩阵实验室。MATLAB 最初的编写目的是提供对由 LINPACK 和 EISPACK 项目开发的矩阵软件的轻松访问，这两个项目共同代表了矩阵计算软件的最新技术。MATLAB 经过多年的发展，得到了许多用户的投入。在大学环境中，它是数学、工程和科学入门和高级课程的标准教学工具。在工业领域，MATLAB 是高效研究、开发和分析的首选工具。MATLAB 具有一系列称为工具箱的特定于应用程序的解决方案。对于大多数 MATLAB 用户来说非常重要，工具箱允许您学习应用专业技术。工具箱是 MATLAB 函数（M 文件）的综合集合，可扩展 MATLAB 环境以解决特定类别的问题。可用工具箱的领域包括信号处理、控制系统、神经网络、模糊逻辑、小波、仿真等。 ## 数学代写|黎曼几何代写Riemannian geometry代考|MATH3405 如果你也在 怎样代写黎曼几何Riemannian geometry这个学科遇到相关的难题，请随时右上角联系我们的24/7代写客服。 黎曼几何是研究黎曼流形的微分几何学分支，黎曼流形是具有黎曼公制的光滑流形，即在每一点的切线空间上有一个内积，从一点到另一点平滑变化。 statistics-lab™ 为您的留学生涯保驾护航 在代写黎曼几何Riemannian geometry方面已经树立了自己的口碑, 保证靠谱, 高质且原创的统计Statistics代写服务。我们的专家在代写黎曼几何Riemannian geometry代写方面经验极为丰富，各种代写黎曼几何Riemannian geometry相关的作业也就用不着说。 我们提供的黎曼几何Riemannian geometry及其相关学科的代写，服务范围广, 其中包括但不限于: • Statistical Inference 统计推断 • Statistical Computing 统计计算 • Advanced Probability Theory 高等概率论 • Advanced Mathematical Statistics 高等数理统计学 • (Generalized) Linear Models 广义线性模型 • Statistical Machine Learning 统计机器学习 • Longitudinal Data Analysis 纵向数据分析 • Foundations of Data Science 数据科学基础 ## 数学代写|黎曼几何代写Riemannian geometry代考|Differentials on an Algebra In differential geometry one equips a topological space with the structure of a differentiable manifold M. This means that locally we have coordinates x^{1}, \ldots, x^{n} identifying an open set with a region of \mathbb{R}^{n} (for some fixed n which is the dimension of the manifold), and that we can apply the usual methods of the calculus of several variables. Further, these local coordinates fit together so that we can talk of differentiable constructions globally over the whole manifold. Locally, on each coordinate patch, we have vector fields \sum_{i} v^{i}(x) \frac{\partial}{\partial x^{i}}, which give a vector at every point of M. Together these vectors span the tangent bundle T M to M. The cotangent bundle T^{*} M is dual to this and the space of ‘1-forms’ \Omega^{1}(M) is spanned by elements of the form \sum_{i} \omega_{i}(x) \mathrm{d} x^{i} in each local patch. Here the \mathrm{d} x^{i} are a dual basis to \frac{\partial}{\partial x^{i}} at each point. One also has an abstract map \mathrm{d} which turns a function f into a differential 1-form$$
\mathrm{d} f=\sum_{i} \frac{\partial f}{\partial x_{i}} \mathrm{~d} x^{i} .
$$We denote by C^{\infty}(M) the smooth (i.e differentiable an arbitrary number of times) real-valued functions on M. This is an algebra, so we can add and multiply such functions. In this book the role of functions on a manifold is going to be played by a ‘coordinate algebra’ A, except that there need not be an actual manifold or even an actual space in the picture. For example, the algebra could be noncommutative. One can still develop a theory of differential geometry over algebras in this case, and in this chapter we look its first layer, which is the differentiable structure. In most approaches to noncommutative geometry this amounts to defining a suitable space of 1-forms \Omega^{1} by its desired properties as an implicit definition of a ‘noncommutative differentiable structure’, as there are no actual open sets or local coordinates. This leads to a much cleaner development of differential geometry as a branch of algebra. We will look at the construction and classification of such 1forms on a variety of algebras and also at the construction of n-forms in general as a differential graded algebra (\Omega, \mathrm{d}, \wedge). ## 数学代写|黎曼几何代写Riemannian geometry代考|First-Order Differentials The reader will likely be familiar with the idea that the smooth real-valued functions C^{\infty}(M) on a manifold M, or the 2 \times 2 complex matrices with complex entries M_{2}(\mathbb{C}), are examples of algebras. A formal definition on an algebra A over a field k, which shall usually be the real numbers \mathbb{R} or the complex numbers \mathbb{C}, but could in principle be, for example, a finite field, is a vector space over k equipped with an associative product which is bilinear, and so satisfies the distributive rules$$
a(b+c)=a b+a c, \quad(a+b) c=a c+b c
$$for all a, b, c \in A. We will assume that our algebras are unital, i.e., have a multiplicative identity or unit 1 , unless otherwise stated. A module E for an algebra A is a vector space over the same field \mathrm{k} which has a \mathrm{k}-linear action of the algebra. The algebra can act on the left, and an example of this is the action of M_{2}(\mathbb{C}) on two-dimensional column vectors by matrix multiplication with the square matrix on the left. Similarly, the set of two-dimensional row vectors has a right action of M_{2}(\mathbb{C}) by matrix multiplication. The identity element in the algebra (in this case the 2 \times 2 identity matrix) has the trivial action. The vital part of the definition is that the action must be compatible with the algebra product,$$
a \cdot(b \cdot e)=(a b) \cdot e \quad \text { (left action), } \quad(e . a) \cdot b=e .(a b) \quad \text { (right action) }
$$for all a, b \in A and e \in E. For our matrix example, these are just associativity of matrix multiplication. A right module means there is a right action of the algebra, and a left module a left action of the algebra. Thus we may say that two-dimensional row vectors form a right module for M_{2}(\mathbb{C}) with action just the matrix product. A bimodule has both left and right module actions such that a \cdot(e . b)=(a \cdot e) . b for a, b \in A and e in the bimodule. Any algebra is a bimodule over itself, for example M_{2}(\mathbb{C}) with the actions of matrix multiplication from the left and from the right. Also we recall that the tensor product over a field is a way of taking products of vector spaces in such a way that it multiplies the dimension. Thus V with basis v_{1}, \ldots, v_{n} and W with basis w_{1}, \ldots, w_{m} have tensor product V \otimes W with basis v_{i} \otimes w_{j} for 1 \leq i \leq n and 1 \leq j \leq m. An example is the tensor product of the space of column 2-vectors with the space of row 2-vectors to give M_{2}(\mathbb{C}) as their tensor product vector space. Tensor product is a bilinear operation and also makes sense for infinite-dimensional vector spaces, where the key defining property is the identity v \otimes \lambda w=v \lambda \otimes w for all \lambda \in \mathbb{R}, v \in V, w \in W. ## 黎曼几何代考 ## 数学代写|黎曼几何代写Riemannian geometry代考|Differentials on an Algebra 在微分几何中，人们为拓扑空间配备了可微流形的结构 M. 这意味着我们在本地有坐标 x^{1}, \ldots, x^{n} 识别具有区域 的开集 \mathbb{R}^{n} (对于一些固定的 n 这是流形的维数），并且我们可以应用通常的几个变量的微积分方法。此外，这些 局部坐标组合在一起，因此我们可以在整个流形上全局讨论可微构造。 在本地，在每个坐标块上，我们都有向量场 \sum_{i} v^{i}(x) \frac{\partial}{\partial x^{i}} ，它在每个点给出一个向量 M. 这些向量一起跨越切线 束 T M 至 M. 余切丛 T^{*} M 与此和 ‘1-forms’ 的空间是双重的 \Omega^{1}(M) 由表单的元素跨越 \sum_{i} \omega_{i}(x) \mathrm{d} x^{i} 在每个本地 补丁中。这里 \mathrm{d} x^{i} 是双重基础 \frac{\partial}{\partial x^{i}} 在每个点。还有一张抽象地图d这变成了一个功能 f 成微分 1-形式$$
\mathrm{d} f=\sum_{i} \frac{\partial f}{\partial x_{i}} \mathrm{~d} x^{i}
$$我们表示 C^{\infty}(M) 上的平滑 (即可微分任意次数) 实值函数 M. 这是一个代数，所以我们可以将这些函数相加和 相乘。在本书中，函数在流形上的作用将由“坐标代数”来扮演 A ，除了在图片中不需要有一个实际的流形甚至是一 个实际的空间。例如，代数可以是不可交换的。在这种情况下，人们仍然可以在代数上发展微分几何理论，在本章 中，我们将研究它的第一层，即可微结构。在非对易几何的大多数方法中，这相当于定义一个合适的 1-形式空间 \Omega^{1} 通过其所需的属性作为“非交换可微结构”的隐式定义，因为没有实际的开集或局部坐标。这导致微分几何作为 代数的一个分支得到了更清晰的发展。我们将研究这种 1 形式在各种代数上的构造和分类，以及 n-一般形式为微 分分级代数 (\Omega, d, \wedge). ## 数学代写|黎曼几何代写Riemannian geometry代考|First-Order Differentials 读者可能熟尓平滑实值函数的概念 C^{\infty}(M) 在歧管上 M ，或者 2 \times 2 具有复杂条目的复杂矩阵 M_{2}(\mathbb{C}), 是代数的 例子。代数的正式定义 A 在一个领域 k ，这通常是实数 \mathbb{R} 或复数 \mathbb{C} ，但原则上可以是，例如，有限域，是 \mathrm{k} 上的向量 空间，具有双线性的关联积，因此满足分配规则$$
a(b+c)=a b+a c, \quad(a+b) c=a c+b c
$$对所有人 a, b, c \in A. 除非另有说明，否则我们将假设我们的代数是单位的，即具有乘法单位或单位 1 。 一个模块 E 对于代数 A 是同一场上的向量空间 \mathrm{k} 它有一个 \mathrm{k} – 代数的线性作用。代数可以作用在左边，一个例子是 M_{2}(\mathbb{C}) 通过矩阵乘法与左侧的方阵对二维列向量进行运算。类似地，二维行向量集的右动作为 M_{2}(\mathbb{C}) 通过矩阵 乘法。代数中的单位元 (在本例中为 2 \times 2 单位矩阵) 具有平凡的作用。定义的重要部分是动作必须与代数积兼 容,$$
a \cdot(b \cdot e)=(a b) \cdot e \quad(\text { left action) }, \quad(e . a) \cdot b=e .(a b) \quad \text { (right action) }


## 有限元方法代写

tatistics-lab作为专业的留学生服务机构，多年来已为美国、英国、加拿大、澳洲等留学热门地的学生提供专业的学术服务，包括但不限于Essay代写，Assignment代写，Dissertation代写，Report代写，小组作业代写，Proposal代写，Paper代写，Presentation代写，计算机作业代写，论文修改和润色，网课代做，exam代考等等。写作范围涵盖高中，本科，研究生等海外留学全阶段，辐射金融，经济学，会计学，审计学，管理学等全球99%专业科目。写作团队既有专业英语母语作者，也有海外名校硕博留学生，每位写作老师都拥有过硬的语言能力，专业的学科背景和学术写作经验。我们承诺100%原创，100%专业，100%准时，100%满意。

## MATLAB代写

MATLAB 是一种用于技术计算的高性能语言。它将计算、可视化和编程集成在一个易于使用的环境中，其中问题和解决方案以熟悉的数学符号表示。典型用途包括：数学和计算算法开发建模、仿真和原型制作数据分析、探索和可视化科学和工程图形应用程序开发，包括图形用户界面构建MATLAB 是一个交互式系统，其基本数据元素是一个不需要维度的数组。这使您可以解决许多技术计算问题，尤其是那些具有矩阵和向量公式的问题，而只需用 C 或 Fortran 等标量非交互式语言编写程序所需的时间的一小部分。MATLAB 名称代表矩阵实验室。MATLAB 最初的编写目的是提供对由 LINPACK 和 EISPACK 项目开发的矩阵软件的轻松访问，这两个项目共同代表了矩阵计算软件的最新技术。MATLAB 经过多年的发展，得到了许多用户的投入。在大学环境中，它是数学、工程和科学入门和高级课程的标准教学工具。在工业领域，MATLAB 是高效研究、开发和分析的首选工具。MATLAB 具有一系列称为工具箱的特定于应用程序的解决方案。对于大多数 MATLAB 用户来说非常重要，工具箱允许您学习应用专业技术。工具箱是 MATLAB 函数（M 文件）的综合集合，可扩展 MATLAB 环境以解决特定类别的问题。可用工具箱的领域包括信号处理、控制系统、神经网络、模糊逻辑、小波、仿真等。