从一个积分不等式证明到一般性结论的推广

采用积分的区间可加性和保序性对一个积分不等式进行了证明,该证明虽然比经典证明复杂,但是从其证明过程中可探索出更加一般的积分不等式.     

证明“有关比例线段”的几种技巧

有关比例线段的几何证明,是证明相似三角形的常见问题,也是初中几何证明的难点.有相当的学生对这方面的几何证明往往是无从下笔.在此,笔者根据多年的教学经验谈谈有关比例线段的几种证明技巧.     

拉格朗日中值定理在方程有根证明题中的应用

对微分中值定理证明方程有根的题型作了分类,分析并讨论了证明中的技巧,及证明中所采用的方法,并对不同例子进行了相应的拓展.     

积分不等式证明技巧解析

基于定积分不等式的证明是高等数学教学中的一个难点的认识,重点解析定积分不等式证明过程中所涉及的知识点,并对不等式证明技巧进行分析与归纳,阐述定积分不等式证明的基本思路和解题技巧．     

关于“费尔马最后定理的证明”一文的评注

本文对“费尔马最后定理的证明”一文作出几点评注，主要结论是该证明仅仅是对费尔马最后定理的部分情形的证明，即并没有完全证明费尔马最后定理     

从一个数学问题的简证谈起

《数学通报》2004年第12期刊登了李明老师对1525号数学问题的证明,由于证明的技巧性较高,《数学通报》2006年第10期发表了刘永钦老师的一个简便证明,但刘老师的证明方法具有局限     

从一个数学问题的简证谈起

《数学通报》2004年第12期刊登了李明老师对1525号数学问题的证明,由于证明的技巧性较高,《数学通报》2006年第10期发表了刘永钦老师的一个简便证明,但刘老师的证明方法具有局限性,不易推广．为此,本文介绍解决这类问题非常有效且十分简明的证明方法．     

二重积分变量代换公式证明的探讨

在一般教材中二重积分变量代换公式的证明通常采用几何的方法,也有部分数学分析教材给与了严格的分析证明,但证明不便直观的几何说明.本文对二重积分变量代换公式进行了一些探讨,给出了一个较简洁直观的分析证明方法.     

有关凸函数的一个定理的改进证明

文[1]．P5．引理1．1．3的证明过程比较复杂、难以理解,本文用另外一种方法(利用函数的单调性、凹凸性和拉格朗日中值定理)对该定理进行了证明．其证明方法比文[1]的证明方法简单、明了,并对定理的结论进行了推广．     

关于Weierstrass定理的证明

对于Weierstrass聚点定理．部分教材通常多采用二分法加区间套定理进行证明．也有教材通过在有界数列中寻找一个单调子列来证明Weierstrass聚点定理,可惜证明过程存在问题．通过对证明过程中出现的问题进行分析．可得到基于单调有界定理的Weierstrass定理的证明．     

An instability theorem for a certain sixth order nonlinear delay differential equation

The aim of this paper is to establish an instability theorem for a certain sixth order nonlinear delay differential equation. The proof of the theorem is based on the use of Lyapunov–Krasovskii functional approach. By this work, we improve an instability result obtained in the literature for a certain sixth order nonlinear differential equation without delay to the instability of the zero solution of a certain sixth order nonlinear delay differential equation.     

关于Lagrange微分中值定理的逆问题

近年来,若干文章对“Lagrange微分中值定理的逆问题”进行了讨论,但其表述均不完整,且证明也较繁琐。本文使用严格凸（严格凹）函数的性质,给出该问题一个条件较弱且表述较完整的结果,其证明也较简洁。     

Gaps in the essential spectrum of pseudo differential operators

A gap theorem of Eastham is extended to pseudo differential operators. The generalized gap theorem is then used to study the essential spectra of pseudo differential operators.     

A new look at Bergström’s theorem on convergence in distribution for sums of dependent random variables

In his 1972Periodica Mathematica Hungarica paper, H. Bergström stated a theorem on convergence in distribution for triangular arrays of dependent random variables satisfying, a ?-mixing condition. A gap in his proof of this theorem is explained and a more general version is proved under weakened hypotheses. The method used consists of comparisons between the given array and associated arrays which are parameterized by a truncation variable. In addition to the main theorem, this method yields a proof of equality of limiting finite-dimensional distributions for processes generated by the given associated arrays as well as the result that if a limit distribution for the centered row sums does exist, it must be infinitely divisible. Several corollaries to the main theorem specialize this result for convergence to distributions within certain subclasses of the infinitely divisible laws.     

de Rham－Hodge－Signature算子的局部指标定理

整体的Ａｔｉｙａｈ－Ｓｉｎｇｅｒ指标定理对于一般的椭圆微分算子都成立．但对于局部指标定理来说，人们只能对具体的算子给予证明．并且各种情况需个别处理．由［６］知本文中证得的ｄｅＲｈａｍ－Ｈｏｄｇｅ－Ｓｉｇｎａｔｕｒｅ算子的局部指标既不是α型也不是β型的．这和经典的椭圆算子情形不同．     

An analytical proof of Ogawa’s determinantal theorem

In this note, we propose a short proof, essentially based on differential calculus, of the Ogawa’s determinantal theorem, which itself is an improvement of another similar theorem.     

On gap rigidity problems for compact Hermitian symmetric spaces

We prove a gap rigidity theorem for diagonal curves in maximal polyspheres of irreducible compact Hermitian symmetric spaces of tube type, which is a dual analog to a theorem obtained by Mok. Motivated by the proof we show that the Chow space of certain totally geodesic submanifolds is affine algebraic, which gives a weaker version of gap rigidity for a class of higher dimensional submanifolds.     

A differential graded approach to the silting theorem

A silting theorem was established by Buan and Zhou as a generalisation of the classical tilting theorem of Brenner and Butler. In this paper, we give an alternative proof of the theorem by using differential graded algebras.     

Quantum resurgence for a class of Airy type differential equations

In this article, we investigate the resurgent properties of divergent WKB solutions of a class of Airy type perturbed differential equations. In particular, we extend and propose a new proof of a reduction theorem, due to Aoki et al. [T. Aoki, T. Kawai, Y. Takei, The Bender-Wu analysis and the Voros theory, in: Special Functions, ICM-90 Satell. Conf. Proc., Okayama, 1990, Springer, Tokyo, 1991, pp. 1-29], near a simple turning point, in the framework of exact WKB analysis. Our scheme of proof is based on a Laplace-integral representation derived from an existence theorem of holomorphic solutions for a singular linear partial differential equation.     

The Hodge–de Rham decomposition theorem and an application to a partial differential equation

The Hodge–de Rham Theorem is introduced and discussed. This result has implications for the general study of several partial differential equations. Some propositions which have applications to the proof of this theorem are used to study some related results concerning a class of partial differential equation in a novel way.