圆柱、正棱柱和长方体的一个有趣共性

文[1]讨论了“圆柱容球”、“圆台容球”和“圆锥容球”等常见旋转体的一个有趣共性,归纳如下共同性质:球与其外切圆柱、外切圆台、外切圆锥表面积之比等于体积之比.文[2]讨论了“多面体容球”的一个有趣共性,即球与其外切多面体的表面积之比等于体积之比.文[3]讨论了“一类旋转体容球”的一个有趣共性,即圆柱、圆锥及圆台的组合旋转体与其内切球的表面积之比等于体积之比.文[1]、文[2]及文[3]都是讨论几何体与其内切球的性质,笔者思考,若将内切球改为内切椭球,会有怎样的性质呢?本文将讨论圆柱、正棱柱及长方体容球与容椭球的关系,现叙述如…     

关于矩阵族G~n(θ,△t)一致有界性的局部(J)条件

本文第一个作者曾基于Kreiss预解条件给出稳定性问题的(J)条件([1]).本文应用[2]中的局部化技巧得到了矩阵族G~n(θ,△t)一致有界(稳定)的局部(J)条件.作为一个有趣的应用,我们在较弱的条件下改进了[2]、[3]、[4]中的主要结果.     

切点三角形的性质初探

文[1]证明了关于三角形面积的一个有趣性质: 若△ABC的内切圆切各边于点D、E、F,且△ABC的外接圆、内切圆半径分别为R、r.则切点△DEF[2]面积.     

圆的切线的一个有趣性质

文[1]研究了准线与准圆的一个关联，受文[1]启发。笔者借助超级画板软件，发现圆的切线的一个有趣性质，现介绍如下．     

关于分层空间度量化的一个问题

利用g-函数研究广义度量空间和度量化,统一了近年来许多有趣的工作.本文回答了[2]中提出的一个问题.所讨论的拓扑空间是正则的.     

双曲线焦点三角形的一个性质

文[1]、[2]给出了双曲线焦点三角形的一些性质，受此启发，经过研究，本文得到双曲线焦点的三角形的一个有趣性质．     

圆锥曲线的一组定值

文[1]给出了椭圆、双曲线的一个有趣性质，笔者经过探究，发现该性质可以推广．     

向量性质的一个有趣推广

在文[1]中由一道高考试题得到了圆锥曲线的一个有趣的向量性质，下面对它作进一步的推广：     

一个数学期望不等式的探讨

利用Fubini定理,证明了两个独立同分布随机变量和与差绝对值之差的期望的精确表达式,该结论蕴含了[1]的主要结果,并讨论了该等式的一个有趣的等价形式.     

四面体内心和旁心的另外两个性质

文[1][3]对三角形内心，旁心的性质进行了研究，文[4]给出了四面体内心与旁心的一个有趣性质，笔者深受启发，探究出空间四面体内心和旁心的另外两个性质，为行文方便，我们把文[4]的两个结论作为本文的两个引理．     

Generalization of a theorem of Luxemburg and Zaanen

We give a generalization of a result of Luxemburg and Zaanen [6] and we deduce some interesting consequences.     

无穷维Banach空间上的逼近定理和弱内向映象的不动点定理

本文在适当的边界条件下证明了ｋｙＦａｎ［１，Ｔｈ，２］逼近定理对严格集压缩映象和凝聚映象在无穷维Ｂａｎａｃｈ空间中的圆环上也成立，作为应用，得到了弱内向映象的非零不动点定理。     

Some properties of E-m semigroups

In this note we study some properties of E-m semigroups, recently defined by Nordahl in [3]. In particular we study connections with power joined and strongly reversible semigroups. We prove, among other things, that an E-m semigroup is a disjoint union of power joined semigroups.The second part of the paper deals with case m = 2, which presents interesting properties. For undefined terminology and notation the reader is referred to [2].     

On the occurrence of the sine kernel in connection with the shifted moments of the Riemann zeta function

We point out an interesting occurrence of the sine kernel in connection with the shifted moments of the Riemann zeta function along the critical line. We discuss rigorous results in this direction for the shifted second moment and for the shifted fourth moment. Furthermore, we conjecture that the sine kernel also occurs in connection with the higher (even) shifted moments and show that this conjecture is closely related to a recent conjecture by Conrey, Farmer, Keating, Rubinstein, and Snaith (2003, 2005) [CFKRS1] and [CFKRS2].     

Strongly regular graphs and spin models for the Kauffman polynomial

We study spin models for invariants of links as defined by Jones [22]. We consider the two algebras generated by the weight matrices of such models under ordinary or Hadamard product and establish an isomorphism between them. When these algebras coincide they form the Bose-Mesner algebra of a formally self-dual association scheme. We study the special case of strongly regular graphs, which is associated to a particularly interesting link invariant, the Kauffman polynomial [27]. This leads to a classification of spin models for the Kauffman polynomial in terms of formally self-dual strongly regular graphs with strongly regular subconstituents [7]. In particular we obtain a new model based on the Higman-Sims graph [17].     

A note on the paper of Kohli and Vashistha

In [1] Kohli and Vashistha gave an analogue of probabilistic version of Pant‘s Theorem ([2], Theorem 1). We note that mappings defined in Examples 3.6 to 3.8 of [1] are not self maps as claimed in the Definitions 3.1 and 3.2. In this context, we provide some relevant examples to complete the interesting results.     

Mapping resolutions of length three I

We produce some interesting families of resolutions of length three by describing certain open subsets of the spectrum of the generic ring for such resolutions constructed in [6].     

The finite–horizon version for a partially–observed stochastic control problem of benesš & rishel

A Bayesian adaptive control problem with several interesting features, due to Bene? and Rishel, was treated as a stochastic control problem with partial observations – and on an infinite horizon with discounting – in thepapers [2] and [10]. We discuss here in full detail the finite–horizon version of that problem, by solving fairly explicitly the associated, fully nonlinear and degenerate, Hamilton-Jacobi-Bellman equation of parabolic type     

On the Converse of Aliprantis and Burkinshaw's Theorem

We prove a complete converse of Aliprantis and Burkinshaw’s Theorem [2]. Also we obtain a generalization of Wickstead’s Theorem [9] about this converse, and we give some interesting consequences. revised 4 April, 18 October, and 26 December 2005     

A real variable restatement of Riemann’s hypothesis

We show that Riemann’s hypothesis is related to the equality of certain interesting subspaces ofL ^p (0,1). Our results generalize an earlier theorem of A. Beurling [2]. Supported in part by grants from the National Science Foundation.