内—p—闭群及其推广

非ｐ—闭群Ｇ叫拟ｐ—闭群，如果有Ｇ的真子群Ｈ，当(?)时．Ｋ就是ｐ—闭群。本文证明了下列定理：定理１拟ｐ—闭群有下述二型：Ⅰ当Ｇ可解时，２≤｜π（Ｇ）｜≤３。Ⅱ当Ｇ不可解时，ａ）Ｇ／Φ（Ｇ）为复阶单群。ｂ）(?)为复阶单群。定理２内—５—闭群有下述二大类型：Ⅰ ５^αｐ^β阶ｐ—基本群。Ⅱ Ｇ／Φ（Ｇ）同构于ＰＳＬ（２，５），Ｓ_ｚ（２^ｑ）（ｑ为奇素数）     

Dirac定理的局部化与Hamilton图

设Ｇ为一个ｎ阶２－连通图，ｎ≥３．若｜Ｄ_ｎ／２（Ｋ_１，３）｜≥２且满足下述条件之一：ｉ）｜Ｄ_ｎ／２（Ｋ_１，３＋ｅ）｜≥２，ii）若Ｋ_１，３＋ｅ→Ｇ，ｘｙ(?)Ｅ（Ｋ_１，３＋ｅ），则ｍａｘ｛ｄＧ（ｘ），ｄＧ（ｙ）｝≥ｎ／２，则Ｇ是一个Ｈａｍｉｌｔｏｎｉａｎ图或其闭包为ｓＰ|⊕Ｈ，这里ｓＰ⊕Ｈ是一类极小２－边连通图．     

非幂零极大子群指数为素数幂的有限群

本文证明了如下结果，１．设ｐ是一个素数，如果有限群Ｇ的每一非幂零的极大子群的指数都为ｐ的方幂，则Ｇ为可解群．２．如果有限群Ｇ的每一非幂零的极大子群的指数为素数幂，则Ｇ／Ｓ（Ｇ）１或ＰＳＬ（２，７），其中Ｓ（Ｇ）表示Ｇ的最大可解正规子群．     

体上右线性方程组的反问题

设Ｆ，Ｋ，Ω分别表示一个任意的体、一个具有对合反自同构的体和一个实四元数体，Ｆ^ｎ表示Ｆ上的ｎ维右向量空间．本文推广和改进了实线性方程组的反问题及一系列结果，解决了Ｆ上右线性方程组更具一般性的反问题（简称ＩＰＳ）：给定ｂ∈Ｆ^s和α_ｉ∈Ｆ^ｎ（ｉ＝１，…，ｍ≤ｎ）满足ｒａｎｋ［α₁，…，α_m］＝ｍ，求所有的ｓ×ｎ矩阵Ａ使Ａα_ｉ＝ｂ（ｉ＝１，…，ｍ）．当ｓ＝ｎ时     

φ－满射环上GLｎ（R）中元素的三角分解

本文结果是：设Ａ是φ－满射环Ｒ上的非拟纯量可逆ｎ×ｎ矩阵，β_j，γ_j（1≤ｊ≤ｎ）是Ｒ中任意元素，它们满足Π_j=1^{nβ_jγ_j＝ｄｅｔＡ，则存在ｎ阶阵Ｂ和Ｃ满足ＰＡＰ－１＝ＢＣ，其中Ｂ是下三角阵，Ｃ是上三角阵，Ｐ∈ＧＬ_ｎ（Ｒ）．进一步，可以取Ｂ使β_j（１≤ｊ≤ｎ）位于Ｂ的主对角线上，同时可以取Ｃ使γ_j（１≤ｊ≤ｎ）位于Ｃ的主对角线上．}     

在奇次Legendre多项式零点上的（0，2）*插值

设Ｐ_ｎ表示ｎ次Ｌｅｓｅｎｄｒｅ多项式，本文考虑多项式（１－ｘ²）Ｐ_ｎ．（ｘ）／ｘ（ｎ为奇数）零点上的（０，２）^*插值问题，得到了这种插值的正则性，显式表达式及收敛性．     

具有两个生成元的SL2(C)的可解子群构造及对Fuchs系统的应用

本文给出ＳＬ₂（Ｃ）中具有两个生成元的可解子群的结构定理,并由单值群的可解性定义一类环面Ｔ²上Ｆｕｃｈｓ系统的可积性,进而研究该系统的解的一些大范围性质．     

投影下的Gronwall不等式

本文对Ｊ．Ｋ．Ｈａｌｅ曾提出的一类广泛的投影下的Ｇｒｏｎｗａｌ不等式问题作了讨论，对满足ｕ（ｔ）≤ａ（ｔ）＋∫_０^tｂ（ｔ－ｓ）ｕ（ｓ）ｄｓ＋∫_０^∞ｃ（ｓ）ｕ（ｔ＋ｓ）ｄｓ，(?)ｔ≥０的函数ｕ（ｔ）∈Ｃ_b⁰（Ｒ₊，Ｒ₊）作了估计．其结果对讨论微分方程的有界解、不变流形及其Ｆｏｌｉａｔｉｏｎ和进一步讨论奇性Ｇｒｏｎｗａｌ不等式都有意义     

三角域上分片二次函数Bernstein多项式的退化性

设Ｓ_２（Ｔ）为三角域Ｔ的二阶剖分，本文给出在Ｓ_２（Ｔ）下分片二次函数f(P)∈Ｃ¹（Ｔ）的Ｂｅｒｎｓｔｃｉｎ多项式的退化性及递推公式。这里的条件Ｓ_２（Ｔ）及Ｃ¹（Ｔ）类都是重要的。我们举例说明更一般情况下分片二次函数Ｂｅｒｎｓｔｃｉｎ多项式的复杂性。     

关于G-Matlis自反模的换环定理

设Ｒ和Ｔ是Ｎｏｅｔｈｅｒ完备半局部环，Ｒ→Ｔ是环同态．本文证明了，若Ｔ是有限生成或ＡｒｔｉｎＲ－模，Ｍ为Ｇ－Ｍａｔｌｉｓ自反Ｒ－模，则对所有ｎ≥０，Ｅｘｔ^Ｒ_ｎ（Ｔ，Ｍ），Ｅｘｔ^Ｒ_ｎ（Ｍ，Ｔ），Ｔｏｒ^Ｒ_ｎ（Ｔ，Ｍ）以及Ｔｏｒ^Ｒ_ｎ（Ｍ，Ｔ）均是Ｇ－Ｍａｔｌｉｓ自反Ｔ－模．所得结果推广了Ｒ．Ｂｅｌｓｈｏｆ的结果．     

Random and Deterministic Triangle Generation of Three-Dimensional Classical Groups III

Let p₁, p₂, p₃ be primes. This is the final paper in a series of three on the (p₁, p₂, p₃)-generation of the finite projective special unitary and linear groups PSU ₃(pⁿ), PSL ₃(pⁿ), where we say a noncyclic group is (p₁, p₂, p₃)-generated if it is a homomorphic image of the triangle group T_{p1, p2, p3} . This article is concerned with the case where p₁ = 2 and p₂ ≠ p₃. We determine for any primes p₂ ≠ p₃ the prime powers pⁿ such that PSU ₃(pⁿ) (respectively, PSL ₃(pⁿ)) is a quotient of T = T_{2, p2, p3} . We also derive the limit of the probability that a randomly chosen homomorphism in Hom(T, PSU ₃(pⁿ)) (respectively, Hom(T, PSL ₃(pⁿ))) is surjective as pⁿ tends to infinity.     

Random and Deterministic Triangle Generation of Three-Dimensional Classical Groups II

Let p ₁, p ₂, p ₃ be primes. This is the second article in a series of three on the (p ₁, p ₂, p ₃)-generation of the finite projective special unitary and linear groups PSU₃(p ⁿ ), PSL₃(p ⁿ ), where we say a noncyclic group is (p ₁, p ₂, p ₃)-generated if it is a homomorphic image of the triangle group T _{p 1, p 2, p 3} . This paper is concerned with the case where p ₁ = 2 and p ₂ = p ₃. We determine for any prime p ₂ the prime powers p ⁿ such that PSU₃(p ⁿ ) (respectively, PSL₃(p ⁿ )) is a quotient of T = T _{2, p 2, p 2} . We also derive the limit of the probability that a randomly chosen homomorphism in Hom(T, PSU₃(p ⁿ )) (respectively, Hom(T, PSL₃(p ⁿ ))) is surjective as p ⁿ tends to infinity.     

A Symmetric Presentation for J 1

Abstract

We give a computer-free proof that the sporadic simple group J ₁ is a isomorphic to the progenitor 2*⁵ : A ₅ factorized over a single relation. Precisely, we prove that J ₁ is defined by the presentation ?x, y, t ∣ x ⁵ = y ³ = (xy)² = 1 = t ² = [y, t] = [y, t ^{x 3} ] = (xt)⁷?.     

Quantum Dynamical coBoundary Equation for finite dimensional simple Lie algebras

For a finite dimensional simple Lie algebra g, the standard universal solution R(x)∈Uq(g)^⊗2 of the Quantum Dynamical Yang-Baxter Equation quantizes the standard trigonometric solution of the Classical Dynamical Yang-Baxter Equation. It can be built from the standard R-matrix and from the solution F(x)∈Uq(g)^⊗2 of the Quantum Dynamical coCycle Equation as . F(x) can be computed explicitly as an infinite product through the use of an auxiliary linear equation, the ABRR equation.Inspired by explicit results in the fundamental representation, it has been conjectured that, in the case where g=sl(n+1)(n?1) only, there could exist an element M(x)∈Uq(sl(n+1)) such that the dynamical gauge transform RJ of R(x) by M(x),

RJ=M₁⁻¹(x)M₂(xqh₁⁾⁻¹R(x)M₁(xqh₂)M₂(x),     

On the convex hull of the multiform numerical range

Let A ₁,…,A_m be nxn hermitian matrices. Definine

W(A ₁,…,A_m )={(xA₁x ^?,…xA_mx ^?):x?C ⁿ ,xx ^?=1}. We will show that every point in the convex hull of W(A ₁,…,A_m ) can be represented as a convex combination of not more than k(m,n) points in W(A ₁,…,A_m ) where k(m,n)=min{n,[√m]+δ _n ² _m+1}.     

P. Hall's covering group and embeddings of countable cc-groups

Let A be an elementary abelian group of order at least p ³ acting on a finite p′-group G that is soluble with derived length d. Assume that γ _c (C _G (a)) has exponent dividing m for any a ∈ A ^#. It is proved that there exist {p, d, c, m}-bounded numbers c ₁ and m ₁ such that γ _{c 1} (G) has exponent dividing m ₁.     

Finite groups with some given systems of Xm‐semipermutable subgroups

Let X be a nonempty subset of a group G. We call a subgroup A of G an X_m‐semipermutable subgroup of G if A has a minimal supplement T in G such that for every maximal subgroup M of any Hall subgroup T₁ of T there exists an element x ∈ X such that AM^x = M^xA. In this paper, we study the structure of finite groups with some given systems of X_m‐semipermutable subgroups (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Adian-Lisenok groups and (U) condition

A group G possesses the property (U) with respect to S if there exists a number M = M(G) such that for each generating set P of the group G there exists an element t ? G for which max _x?S |t ^?1 xt| _P ≤ M. It is proved that the well-known Adian-Lisenok groups possess the property (U). In connection with the problem on finding infinite groups with the property (U), which is stated in a joint unpublishedwork by D.Osin and D. Sonkin, it is shown that for any odd n ≥ 1003 there is a continuum set of non-isomorphic, i.e. simple groups with the property (U) in the variety of groups satisfying the identity x ⁿ = 1.     

Two Conditions for Infinite Groups to Satisfy Certain Laws

Let G be an infinite group and m {2^k | k N^*}. In this paper, we prove that G satisfies the law [x_m, y_m] = 1 if and only if in any two infinite subsets X and Y of G, there exist a X and b Y such that [a^m,b^m] = 1. We also prove that G satisfies the law (x₁^mx₂^m x_n^m)² = 1 if and only if in any n infinite subsets X₁, X₂,..., X_n, there exist a_i X_i (i = 1,..., n) such that (a₁^ma₂^m a_n^m)² = 1.2000 Mathematics Subject Classification: 20F99     

Bordism-Finiteness and Semi-simple Group Actions

We give bordism-finiteness results for smooth S ³-manifolds. Consider the class of oriented manifolds which admit an S ¹-action with isolated fixed points such that the action extends to an S ³-action with fixed point. We exhibit various subclasses, characterized by an upper bound for the Euler characteristic and properties of the first Pontryagin class p ₁, for example p ₁ = 0, which contain only finitely many oriented bordism types in any given dimension. Also we show finiteness results for homotopy complex projective spaces and complete intersections with S ³-action as above.