THE FUNDAMENTAL GROUP OFTHE AUTOMORPHISM GROUP OFA NONCOMMUTATIVE TORUSTHE FUNDAMENTAL GROUP OFTHE AUTOMORPHISM GROUP OFA NONCOMMUTATIVE TORU

1. IntroductionGiven a locally compact abelian group G and a multiplier p on G, one can associate tothem the twisted group C*-algebra C*(G, p), which is the universal object for unitary prepresentations of G. C* (Zm, p) is said to be a noncommutative torns of rank m and denotedby A.. The multiplier p determines a subgroup S. of G, called its symmetry group, andthe multiplier p is called totally skew if the symmetry group S. is trivial. And A. is calledcompletely irrational if p is totally…     

凸域内弦的平均长度

本文研究了凸域内弦的平均长度.通过广义支持函数与凸域的弦幂积分,建立了凸域内弦的平均长度的一般公式,并用此公式得出了圆域和矩形域内弦的平均长度.     

一个布朗运动最佳时机的选择

本文进一步讨论了文献所给出的布朗运动模型的最佳时机的选择问题，并用随机游动模型作为有趋势布朗运动的近似，给出了对应随机模型的最佳时机，其思想方法是有实际意义的．     

THE LIMIT SET OF A CONTINUOUS SELF-MAP OF THE TREE

Let f denote a continuous map of a tree T to itself. A point x ∈ T is called a 7-limit point of f if it is both an ω-limit point and an α-limit point. In the present paper, we show that (1) Ω-Γ is countable, (2) A -Γ and P - Γ are either empty or countably infinite, where P denotes the closure of the set of periodic points P.     

关于非亏损矩阵特征值的扰动

正规阵是非亏损矩阵的特殊情形.关于正规阵特征值的扰动,Hoffman和Wielandt在1957年提出了一个重要的定理:若N,A均为n×n正规阵,其特征值分别为{v_i}_i~n=1和{α_i}_i~n=1,则存在1,2,…,n的一个排列π(1),π(2),…,π(n),使得     

幂级数系数重排使型不变的必要条件

根据幂级数系数重排级不变的充要条件，对比研究了幂级数系数的重排与此级数的和函数的型之间的关系，得到了幂级数系数重排型不变的一些必要条件。     

关于正规矩阵特征值的扰动

设N与A均为n×n正规矩阵,其特征值分别为{v_i}_(i=1)~n与{α_i}_(i=1)~n。Hoffman和Wielandt证明了:存在1,2,…,n的一个排列π(1),π(2),…,π(n),使得|| ||_F表示Frobenius范数。 当N为n×n Hermite矩阵,A为n×n可对称化矩阵,即存在非奇异矩阵Q=I X,使得Q~(-1)AQ为Hermite矩阵时,Stewart证明了:如果N与A的特征值分别     

一个特征标环素谱的连通性

本文确定了一个有限群特征标环通过代数整数环扩张后素谱的结构，在此基础之上，利用与[1]中类似的方法证明了这个扩张后的特征标环素谱的连通性。同时还计算了有限群的复类函数空间的幂等元．     

A METHOD PROVING THE UNIQUENESS OF THE LIMIT CYCLE OF THE QUADRATIC SYSTEM

ＡＭＥＴＨＯＤＰＲＯＶＩＮＧＴＨＥＵＮＩＱＵＥＮＥＳＳＯＦＴＨＥＬＩＭＩＴ　ＣＹＣＬＥＯＦＴＨＥＱＵＡＤＲＡＴＩＣＳＹＳＴＥＭＸｕＳｉｌｉｎ（徐思林）（ＱｉｎｇｄａｏＵｎｉｖｅｒｓｉｔｙ，青岛大学，邮编：２６６０７１）ＺｈｕＹｕｇｅｎ（朱豫根）（Ｎａ...     

阵的模数最大的特征根的幅角

<正> 设有元素为实数或复数的方阵(?)多项式(?)做 A 的特征多项式,这里 E 为么阵,λ为未知量,这个多项式的根叫做 A 的特征根.现在采用下面的一些记号.我们用 A~(?)表 A 的共轭转置阵;对于任意正整数 K,令(?)(?)Farnell 和 Gautscui 曾证明:若ω为阵 A 的具有最大模数的特征根,则ω的模数为数列(?)的极限,即     

THE DIMENSIONS OF A KIND OF FUNCTIONS

This paper giws the Bouligand dimensions of a kind of functions.     

一个淋病扩散模型的定性分析

本文利用奇点理论与Ｂｅｎｄｉｘｓｏｎ定理对淋病扩散模型进行了定性分析,给出了可行平衡点附近,特别是高阶平衡点附近轨线的定性结构,研究了可行平衡点的全局渐近稳定性,得到了完整的结果。     

A MODEL OF THE ENZOOTIOLOGY OF LYME DISEASE IN THE ATLANTIC NORTHEAST OF THE UNITED STATES

A mathematical model is presented for the dynamics of the rate of infection of the Lyme disease vector tick Ixodes dammini (Acari: Ixodidae) by the spirochete Borrelia burgdorferi, in the Atlantic Northeast of the United States. According to this model, moderate reductions in the abundance of white-tailed deer Odocoileus virginianus may either decrease or increase the spirochete infection rate in ticks, provided the deer are not reservoir hosts for Lyme disease. Expressions for the basic reproductive rate of the disease are computed analytically for special cases, and it is shown that as the basic reproductive rate increases, a proportional reduction in the tick population produces a smaller proportional reduction in the infection rate, so that vector control is less effective far above the threshold. The model also shows that control of the mouse reservoir hosts Peromyscus leucopus could reduce the infection rate if the survivorship of juvenile stages of ticks were reduced as a consequence. If the survivorship of juvenile stages does not decline as the rodent population is reduced, then rodent reduction can increase the spirochete infection rate in the ticks.     

A CHARACTERIZATION OF THE EMBEDDABILITY OF GRAPHS ON THE SURFACE OF GIVEN GENUS

§1.ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｓｙｍｂｏｌｓａｎｄｔｈｅｔｅｃｈｎｉｃａｌｔｅｒｍｓｎｏｔｅｘｐｌａｉｎｅｄｉｎｔｈｉｓｐａｐｅｒｃａｎｂｅｆｏｕｎｄｉｎ[1]ａｎｄ[3].ＡｇｒａｐｈｉｓｏｆｔｅｎｄｅｎｏｔｅｄｂｙＧ=(Ｖ,Ｅ),υ=｜Ｖ｜ａｎｄε=｜Ｅ｜ａｒｅｃａｌｌｅｄｉｔｓｏｒｄｅｒａｎｄｓｉｚｅｒｅｓｐｅｃｔｉｖｅｌｙ.ＩｔｈａｓｂｅｅｎｓｈｏｗｎｂｙＲ.Ｄｕｋｅ[4]ｔｈａｔｉｆａｃｏｎｎｅｃｔｅｄｇｒａｐｈＧｈａｓｅｍｂｅｄｄｉｎｇｓ(ｏｒ2-ｃｅｌｌｅｍｂｅｄｄｉｎｇｓｉｎＤｕｋｅ’ｓｔｅｒｍｉ…     

一类非线性系统解的有界性

研究了一类非线性微分系统解的有界性 ,所获结果可应用于Li啨ｎａｒｄ类型的方程 ,改进与扩展了众多已有文献中的结果