极大子因子

若N是一个Ⅱ1型因子,G是一个有限群且在N上有一个真外作用α,则当G的阶是素数对,N是Ⅱ1型因子M=N(?)αG的极大子因子．另一方面,假设 N(?) M是Ⅱ1型因子的一个包含,M(?)M1是N(?)M的基本构造,[M:N]= p∈N是素数,N’∩ M=CI,N’∩M1是交换的,N,(?)M深度为2,则N是M的极大子因子．     

N=2^t点DFT的快速卷积算法

从所周知,循环卷积和离散富里叶变换(DFT)可以互相计算,只要得到其中一个的快速算法就可导出另一个的快速算法。循环卷积目前已有乘法量为O(N)的最佳算法(特别是当N较小时),为此关键是如何将DFT转化为循环卷积,当DFT的长度N=p(p为素数),Rader利用有限域GF(p)的乘法群是循环群就成功地将p点DFT转化为Q(p)(F(p)为户的Euler函数)点循环卷积;当N=p~e时,由于商环Z/(p~e)存在F(p~c)阶元素,人们也成功地将p~c点DFT转化为P(p~(c-1))一系列循环卷积,即一个y(p~c)点循环卷积,二个P(p~(c-1))点     

On the Normal Subgroup with Exactly Two G-Conjugacy Class Sizes

Let G be a finite group with a non-central Sylow r-subgroup R,Z(G) the center of G,and N a normal subgroup of.G.The purpose of this paper is to determine the structure of N under the hypotheses that N contains R and the G-conjugacy class size of every element of N is either 1 or m.Particularly,it is shown that N is Abelian if N ∩ Z(G)=1 and the Goeonjugacy class size of every element of N is either 1 or m.     

A GENERALIZATION OF COMPLETE GROUPS

Let G be a finite group and let G be the semi-direct product of a normal subgroup N and a subgroup K. In [1], conditions were found which are equivalent to the existence of a normal complement to N in G. We consider the structure of groups N for which the above condition always holds. Thus we use Bechtell's results to gain information on groups N such that if G is a semi-direct product of N and a subgroup K, then N is a direct factor of G, for all G. It is an old result that a group N is complete if and only if whenever N is a normal subgroup of G, then N is a direct factor of G, [4]. Hence it is not surprising that complete groups are part of our result. Moreover a group N is complete if and only if N is isomorphic to Aut(N) under the mapping σ(n) = σ _n , where σ _n is the inner automorphism induced by n. This remark leads us to consider groups N which contain a subgroup H such that H is isomorphic to Aut(N) under σ: H → Aut(N). All groups considered here are finite. The results found here do not parallel the results found in the author's dissertation for Lie algebras. There it is shown that only complete Lie algebras have the desired property. Thus, these results provide an example of when the theory of Lie algebras diverges from that of groups.     

内交换p群的中心扩张(Ⅱ)

设N,H是任意的群.若存在群G,它具有正规子群N≤Z(G),使得N≌N且G/N≌H,则称群G为N被H的中心扩张.本文完全分类了当N为循环p群,H为内交换p群时,N被H的中心扩张得到的所有不同构的群.     

Multiparametric Families of Solutions of the Kadomtsev–Petviashvili-I Equation,the Structure of Their Rational Representations,and Multi-Rogue Waves

We construct solutions of the Kadomtsev–Petviashvili-I equation in terms of Fredholm determinants. We deduce solutions written as a quotient of Wronskians of order 2N. These solutions, called solutions of order N, depend on 2N?1 parameters. They can also be written as a quotient of two polynomials of degree 2N(N +1) in x, y, and t depending on 2N?2 parameters. The maximum of the modulus of these solutions at order N is equal to 2(2N + 1)². We explicitly construct the expressions up to the order six and study the patterns of their modulus in the plane (x, y) and their evolution according to time and parameters.     

套代数理想的距离公式

设Ｎ是Ｈｉｌｂｅｒｔ空间Ｈ上的一个完备套,是Ｎ上的标准谱测度．本文给出了Ｈ上任一有界线性算子Ｔ到套代数Ａｌｇ　Ｎ的Ｌａｒｓｏｎ理想ＲＮ的距离公式为ＡｌｇＮ的半根理想,则ｄ（Ｔ,ＲＮ）＝ｓｕｐ｛ｉＮ（Ｔ）：Ｎ｝．     

表大偶數為一個素數及一個不超過四個素數的乘積之和——廣義Riemann猜測下之結果

<正> 引言 本文之目的是在證明作者在[1]內所提及的若干結果,本文所有的結果,均在廣義的Riemann猜測之下,而獲得的. 現在,先將廣義的Riemann猜測述於下:     

The Bergman‐Shelah preorder on transformation semigroups

Let $\mathbb {N}^\mathbb {N}Let $\mathbb {N}^\mathbb {N}$ be the semigroup of all mappings on the natural numbers $\mathbb {N}$, and let U and V be subsets of $\mathbb {N}^\mathbb {N}$. We write U?V if there exists a countable subset C of $\mathbb {N}^\mathbb {N}$ such that U is contained in the subsemigroup generated by V and C. We give several results about the structure of the preorder ?. In particular, we show that a certain statement about this preorder is equivalent to the Continuum Hypothesis. The preorder ? is analogous to one introduced by Bergman and Shelah on subgroups of the symmetric group on $\mathbb {N}$. The results in this paper suggest that the preorder on subsemigroups of $\mathbb {N}^\mathbb {N}$ is much more complicated than that on subgroups of the symmetric group.     

相对半投射和直投射模

In this paper, the ＂relative＂ version of semi-projectivity is considered. Let M and N be modules. N is called M-semi-projective, if any homomorphism from N to an M-eyclie submodule f（M） of N can be factored through to a homomorphism from N to M and f, where f∈[M, N]. Some properties of relative semi-projectivity are obtained. Next, we consider a wider class of ＂elatively semi-projective＂ modules such as ＂elatively direct-projective＂ modules which were introduced by Nicholson and Zhou. Several properties of their homomorphisms are also obtained.     

Ass（M／N） and Ann（M／N） on the Noetherian Module M

Let R is a noetherian ring,M is a finitely generated R-module.This paper studies the relationbetween associated prime Ass(M/N)and annihilator Ann(M/N),and has given the necessary andsufficient conditions of Ass(M/N)=Ann(M/N).     

Wavelet Transforms for Semidirect Product Groups with Not Necessarily Commutative Normal Subgroups

Let G be the semidirect product group of a separable locally compact unimodular group N of type I with a closed subgroup H of Aut(N). The group N is not necessarily commutative. We consider irreducible subrepresentations of the unitary representation of G realized naturally on L²(N), and investigate the wavelet transforms associated to them. Furthermore, the irreducible subspaces are characterized by certain singular integrals on N analogous to the Cauchy-Szegö integral.     

幂零Hall π-子群的存在性

本文首先将Ｈａｌ定理推广为：设Ｎ为Ｇ的正规子群，若Ｎ为Ｅｎπ群，Ｇ／Ｎ为Ｄπ群，则Ｇ为Ｄπ群．在此基础上得到了群Ｇ为Ｅｎπ群的充要条件为：（１）Ｇ存在正规子群Ｎ，满足Ｎ及Ｇ／Ｎ为Ｅｎπ群；（２）对任意ｐ∈π，任意ｑ∈π ｛ｐ｝及任意ｐ 元素ｘ，ＣＧ（ｘ）含Ｇ的Ｓｙｌｏｗｑ 子群．另外，我们对非Ａｂｌｅ单群的情形也进行了一些讨论．     

Classification of Special Anosov Endomorphisms of Nil-manifolds

In this paper we give a classification of special endomorphisms of nil-manifolds:Let f:N/Γ → N/Γ be a covering map of a nil-manifold and denote by A:N/Γ → N/Γ the nil-endomorphism which is homotopic to f. If f is a special T A-map, then A is a hyperbolic nil-endomorphism and f is topologically conjugate to A.     

A FAST SINE TRANSFORM ALGORITHM FOR TOEPLITZ MATRICES AND ITS APPLICATIONS

In this paper, a fast algorithm for the discrete sine transform(DST) of a Toeplitz matrix of order N is derived. Only O(N log N) O(M) time is needed for the computation of M elements. The auxiliary storage requirement is O(N). An application of the new fast algorithm is also discussed.     

套代数的直和分解

本文主要研究套代数的直和分解。刻划了满足条件的交换子空间格Ｌ的结构，其中Ｒ是套代数的某一特殊子空间；得到了套代数分解成对角代数与某些特殊理想（例如：Ｊａｃｏｂｓｏｎ根或者Ｌａｒｓｏｎ理想）的直和的充要条件，同时也刻划了的一个范数闭左理想上Ｊ＿Ｎ最后，研究了对角代数与某些超因果理想直和的结构。     

内交换p群的中心扩张(Ⅳ)

设N,H是任意的群.若存在群G,它具有正规子群≤Z(G),使得≌N且G/≌H,则称群G为N被H的中心扩张.本文完全分类了当N为p~3阶初等交换p群及H为内交换p群时,N被H的中心扩张得到的所有不同构的群.从而我们完全分类了初等交换p群被内交换p群的中心扩张得到的所有不同构的群.     

Inverse Near Permutation Semigroups

A transformation semigroup over a set X with N elements is said to be a near permutation semigroup if it is generated by a group G of permutations on N elements and by a set H of transformations of rank N - 1. In this paper we give necessary and sufficient conditions for a near permutation semigroup S = ‹G,H›, where H is a group, to be inverse. Moreover, we obtain conditions which guarantee that its semilattice of idempotents is generated by the idempotents of S of rank greater than N - 2 or N - 3.     

具偏差变元的中立型微分方程正周期解的存在性

By means of an abstract continuation theorem, the existence criteria are established for the positive periodic solutions of a neutral functional differential equation dN/dt=N(t)[a(t)-β(t)N(t)-b(t)N(t-a(t))-c(t)N(t-τ(t))]     

THE SPECTRAL PROPERTIES OF THE ITERATION MATRIX OF REGULAR SPLITTINGS FOR AN M-MATRIX

Let A=M-N be a regular splitting of an M-matrix. We study the spectral properties of the ineration matrix M-1N. Under a mild assumption on M-1 N. some necessary and sufficent conditions such that p(M-1N)=1 are obtained and the algebraic multiplicity and the index associated with eigenvalue 1 in M-1N are considered.