具有逆断面的正则半群的同余的表示

具有道断面S°的正则半群可表示为有Saito's结构的半群W（I，S°，Λ，*，α，β）.我们利用由I，S°和Λ上的同余构成的所谓同余聚抽象地表示这类半群上的同余，进而给出了这类半群的同态象的构造法．     

Representation of congruences on regular semigroups with inverse transversals

For a regular semigroup with an inverse transversal, we have Saito’s structureW(I,S ^o, Λ, *, {α, β}). We represent congruences on this kind of semigroups by the so-called congruence assemblage which consist of congruences on the structure component partsI,S ^o and Λ. The structure of images of this type of semigroups is also presented. This work is supported by Natural Science Foundation of Guangdong Province     

The overpartition function modulo small powers of 2

In a recent paper, Fortin et al. (Jagged Partitions, arXivmath. CO/0310079, 2003) found congruences modulo powers of 2 for the values of the overpartition function in arithmetic progressions. The moduli for these congruences ranged as high as 64. This note shows that for a set of integers of arithmetic density 1.     

幂格的同余关系

研究分配格的幂格的同余关系,给出幂格的同余关系格的一些重要性质,并得到幂格的一个同余类和同余关系格的两个交半格。     

K11-代数的主同余关系的可补性

研究K11-代数的主同余关系的可补性,给出K11-代数的主同余关系是可补的充要条件。     

Computing congruence lattices of finite lattices

An inequality between the number of coverings in the ordered set of join irreducible congruences on a lattice and the size of is given. Using this inequality it is shown that this ordered set can be computed in time , where .

     

集对代数软代数的集对表示

指出文[1]中的软代数表示定理（定理2．2）的错误,给出修改后的软代数表示定理。另外,讨论了集对代数的理想、同余关系和同余理想。     

正则纯整群带的算子半群和同余网

正则半群Ｓ的同余格（Ｓ）上的算子Ｋ，ｋ，Ｔ和ｔ定义如下：对于ρ∈Ｓ，ρＫ和ρｋ（ρＴ和ρｔ）分别是与ρ有相同核（迹）的最大和最小同余．我们确定了所有正则纯整群带的同余格上由Ｋ，ｋ，Ｔ和ｔ生成的算子半群．并确定了正则纯整群带上任意同余的同余网．     

Congruence lattices of algebras--- the signed labelling

For an arbitrary algebra a new labelling, called the signed labelling, of the Hasse diagram of is described. Under the signed labelling, each edge of the Hasse diagram of receives a label from the set . The signed labelling depends completely on a subset of the unary polynomials of and its inspiration comes from semigroup theory. For finite algebras, the signed labelling complements the labelled congruence lattices of tame congruence theory (TCT). It provides a different kind of information about those algebras than the TCT labelling particularly with regard to congruence semimodularity. The main result of this paper shows that the congruence lattice of any algebra admits a natural join congruence, denoted , such that satisfies the semimodular law. In an application of that result, it is shown that for a regular semigroup , for which in , is actually a lattice congruence, coincides with , and satisfies the semimodular law.

     

W－理想与W－软代数

本文给出了Ｗ－理想与Ｗ－软代数的定义，主要结果有（Ⅰ）：（ｄ］，（ｄ＿１］分别是软代数Ｆ的同余理想，ｄ＿１≥ｄ，若（ｄ］是Ｗ－理想，则（ｄ＿１］是Ｗ－理想。（Ⅱ）：分别给出了软代数Ｆ，商软代数Ｆ／θ、软代数的直积Ｆ＝ПＦ＿ｉ是Ｗ－软代数的充分必要条件。     

Quadratic forms and congruences for ℓ-regular partitions modulo 3, 5 and 7

Let $b_{\ell }(n)$ be the number of ℓ-regular partitions of n. We show that the generating functions of $b_{\ell }(n)$ with $\ell =3,5,6,7$ and 10 are congruent to the products of two items of Ramanujan's theta functions $\psi (q)$, $f(-q)$ and ${(q;q)}_{\infty }^3$ modulo 3, 5 and 7. So we can express these generating functions as double summations in q. Based on the properties of binary quadratic forms, we obtain vanishing properties of the coefficients of these series. This leads to several infinite families of congruences for $b_{\ell }(n)$ modulo 3, 5 and 7.     

幂交半格上的交同余及其性质

给出了幂交半格上几个具体的交同余,证明了任意多个交同余的并是交同余,并指出幂交半格的交同余类是子交半格,介绍了幂交半格上由θ诱导的交同余具有保并性和保序性。     

A Characterization for Windowed Fourier Orthonormal Basis with Compact Support

Let g(x) ∈L ²(R) and ğ(ω) be the Fourier transform of g(x). Define g _mn (x) = e ^imx g(x−2πn). In this paper we shall give a sufficient and necessary condition under which {g _mn (x)} constitutes an orthonormal basis of L ²(R) for compactly supported g(ω) or ˘(ω). Received March 25, 1999, Revised November 5, 1999, Accepted September 6, 2000     

平衡半拟补Ockham代数的滤子

一个平衡半拟补Ockham代数(简称bdpO-代数)是一个〈2,2,1,1,0,0〉类型的代数(L;∧,∨,f,*,0,1).其中(L;f)是Ockham代数,(L;*)是半拟补代数,且一元运算f和*由恒等式[f(x)]*=f2(x)与f(x*)=x**所连结.本文讨论bdpO-代数中滤子的性质及其同余特征,并刻画某些同余一致与同余凝聚性质.     

Normalizers of the congruence subgroups of the Hecke group II

Let . Let be an ideal of and let be the maximal ideal of such that . Then . In particular, if is square free, then is self-normalized in .

     

Normalizers of the congruence subgroups of the Hecke group

Let cos and let be the Hecke group associated to . In this article, we show that for a prime ideal in , the congruence subgroups of are self-normalized in .

     

On recurrences for sums of powers of binomial coefficients

The recurrence for sums of powers of binomial coefficients is considered and a lower bound for the minimal length of the recurrence is obtained by using the properties of congruence.

Video abstract

For a video summary of this paper, please visit http://www.youtube.com/watch?v=jwy6B4aYR-Q.     

模糊半群上的模糊同余及其扩张

给出模糊半群上的模糊同余的概念，并进一步研究它的一些基本代数性质。同时研究带有模糊半群上的模糊同余扩张性质(FCEPF)的半群类，得到一个半群有模糊半群上的模糊同余扩张性质、有模糊同余扩张性质(FCEP)、有同余扩张性质(CEP)三个条件是等价的。     

Characterizing the number of coloured m-ary partitions modulo m,with and without gaps

In a pair of recent papers, Andrews, Fraenkel and Sellers provide a complete characterization for the number of $m$-ary partitions modulo $m$, with and without gaps. In this paper we extend these results to the case of coloured $m$-ary partitions, with and without gaps. Our method of proof is different, giving explicit expansions for the generating functions modulo $m$.