KdV方程的延拓结构

利用外微分形式系统和Lie代数表示理论提出了求解非线性波方程Lax对的延拓结构理论,该方法是构造非线性波方程Lax对的系统最有效的方法.其关键在于如何给出延拓代数的具体表示,如微分算子表示或矩阵表示.如果一个非线性波方程具有非平凡的延拓代数,则称其延拓代数可积,本篇论文主要利用延拓结构理论,讨论KdV方程的解,同时给出...     

最小阻力功路径方程的Lei群分类及其对称性化简

重新考察虑了,最早由Pakdemirli [Pakdemirli M.Proceedings of the Institution of Mechanical Engineers,Part C :Journal of Mechanical Engineering Science,2009 ,223(5):1113-1116]提出的描述最小阻力功的路径方程.将Lie群理论应用于一般方程,提出了关系任意高程函数群的分类.利用对称性,确定群不变解,并利用正则坐标,降低方程的阶次.     

耦合KdV方程的延拓结构

主要利用延拓结构理论,对Hirota-Satsuma耦合KdV方程进行研究,得到了该方程延拓代数对应的Lax对.     

基于纤维丛表述的李变换群延拓群算子

本文提出积流形李变换群延拓群的概念，并应用纤维丛方法解决延拓群算子中的系数问题，进而讨论其在黎曼流形中的一个应用．     

欧氏群与二次曲线方程的化简

讨论欧氏群E(2)在二次曲线方程化简理论中的应用.在此背景下,给出二次方程化简的方法;讨论了二次曲线方程的若干性质.     

非线性户田晶格方程的延拓结构（英文）

本文研究户田晶格方程的延拓结构.利用非交换微分和求差分微分方程延拓结构的方法,得到户田晶格方程的拉克斯对.     

Carnot群上的Hardy型不等式和唯一延拓性

给出了一般Carnot群上的L~p加权Hardy型不等式,1p+∞,由此导出了Hardy-Sobolev型不等式.作为对该不等式的一个应用,考虑了一类带奇异位势的p-sub-Laplace方程,对其弱解建立了二重性和唯一延拓性.     

SL(3,C)中一类子群的可解群的结构与Fuchs方程的可积性

给出了SL(3,C)的一类子群中具有两个生成元的可解群的结构,并应用于方程W"'-λp(z)w'=0.对此方程,由Fuchs方程的单值群的可解性与其可积性的关系,得到了几个结果.     

复域双周期Riccati方程解空间极限集的复杂性

研究了一个复域上双周期系数的Riccati方程,证明了其解空间可分成三个不相交的子空间,其中一个子空间为闭集,所有周期解的全解析延拓的闭包包含在这个子空间内并形成一个完备子集。该子集在解的延拓变换群下是最小不变闭集,可能具有分形结构,而任一周期解的全解析延拓均在此子集内稠密。     

SL(2,R)和Ernst方程

近年来,利用孤子理论的方法从不同角度对Ernst方程进行的研究,取得了不少进展我们将指出,基于作者们在Wahlquist和Estabrook工作的基础上提出的延拓结构理论,可以全面而系统地概括这些成果,并推进这方面的研究. 我们将以Harrison曾讨论过的情形为例,通过求解延拓结构的基本方程,得到Ernst方程的一个SL(2,R)×R′(l)延拓结构,这是Harrison 所没有完成的.我     

Gröbner–Shirshov Basis for HNN Extensions of Groups and for the Alternating Group

In this article, we generalize the Shirshov's Composition Lemma by replacing the monomial order for others. By using Gröbner–Shirshov bases, the normal forms of HNN extension of a group and the alternating group are obtained.     

Curve selection Lemma for semianalytic sets and conjugacy classes of finite order in Lie groups

Using a strong version of the Curve Selection Lemma for real semianalytic sets, we prove that for an arbitrary connected Lie group G, each connected component of the set E_n(G)of all elements of order n in G is a conjugacy class in G. In particular, all conjugacy classes of finite order in G are closed. Some properties of connected components of E_n(G) are also given.     

关于Thompson的一个结果的注记

本文改进了J .G .Thompson在JournalofCombinatorialTheory ,1 (1 96 6 )中得到的一个有用的引理的结果 .     

Relative hyperbolicity and Artin groups

This paper considers the question of relative hyperbolicity of an Artin group with regard to the geometry of its associated Deligne complex. We prove that an Artin group is weakly hyperbolic relative to its finite (or spherical) type parabolic subgroups if and only if its Deligne complex is a Gromov hyperbolic space. For a two-dimensional Artin group the Deligne complex is Gromov hyperbolic precisely when the corresponding Davis complex is Gromov hyperbolic, that is, precisely when the underlying Coxeter group is a hyperbolic group. For Artin groups of FC type we give a sufficient condition for hyperbolicity of the Deligne complex which applies to a large class of these groups for which the underlying Coxeter group is hyperbolic. The key tool in the proof is an extension of the Milnor-Svarc Lemma which states that if a group G admits a discontinuous, co-compact action by isometries on a Gromov hyperbolic metric space, then G is weakly hyperbolic relative to the isotropy subgroups of the action.      

Wiener's lemma for twisted convolution and Gabor frames

We prove non-commutative versions of Wiener's Lemma on absolutely convergent Fourier series (a) for the case of twisted convolution and (b) for rotation algebras. As an application we solve some open problems about Gabor frames, among them the problem of Feichtinger and Janssen that is known in the literature as the ``irrational case'.

     

A proof of the Morse-Bott Lemma

It is often said that the Morse-Bott Lemma can be viewed as a “parameterized” Morse Lemma, and its proof should follow from the differentiability of the methods used to prove the Morse Lemma. The goal of this expository paper is to fill in the details. We present Palais' proof of the Morse Lemma using Moser's path method, which yields the necessary differentiability.     

On the structure of linear semigroups

Green's Lemma [1, Lemma 2.2] is one of the most important theorems in the theory of semigroups. The main purpose of this note is to establish a generalized Green's Lemma and a generalized Clifford and Miller's Theorem [1, p. 59] in linear semigroups. A generalized Green's Lemma describes the behavior of certain mappings between two distinct D-classes.     

关于一类随机矩阵特征根极限分布的注记

一 引言 考虑k个p维总体X_1,X_2,…,X_k。假定它们都服从正态分布,其均值向量分别是(ξ_(1i),ξ_(2i),…,ξ_(pi)),i=1,2,…,k,且具有共同的协方差矩阵∑=(σ_(ij)),i,j=1,2,…,p。考虑矩阵