有限部分保序变换半群POn的具有某种性质的极大子半群

本文研究了有限链上的部分保序变换半群Pon.通过对其幂等元的分析,获得TPOn的极大正则子半群和极大幂等元生成子半群的结构与分类.     

全正则子半群构成链的正则半群(英文)

本文考虑全正则子半群构成链的正则半群,得到了正则半群具有全正则子半群构成链的一个充分必要条件,这推广了Jones关于具有全正则子半群构成链的逆半群的结果.特别地,建立了具有全正则子半群构成链的完全0-单半群的结构.     

模糊正则子半群的度量

本文主要研究模糊正则子半群的度量问题,利用模糊正则子半群度讨论了正则半群的模糊子集是模糊正则半群的程度。首先,文章通过[0,1]上的蕴含给出了模糊正则子半群度的定义。其次,利用正则半群模糊集的(强)水平集得到了模糊正则子半群度的等价刻画。最后,讨论了任意多个模糊子集的交、直积的模糊正则子半群度以及正则半群的模糊子集在同态映射下像与原像的模糊正则子半群度的性质。     

幂等元生成子半群为完全正则半群的拟完全正则半群

论文主要刻画了幂等元生成子半群为完全正则半群的拟完全正则半群. 并讨论了满足该类半群的一些子类.     

半群M_n的主因子的极大正则子半群

设Sing_n是[n]上的奇异变换半群,得了变换半群M_n={α∈Sing_n:max{|xα~(-1)}≥|im(α)|(x∈im{α))}的主因子的极大正则子半群的完全分类.     

广义模糊子半群和广义模糊完全正则子半群

给出了广义模糊子半群和广义模糊完全正则子半群的定义并在此定义下推得了它们的一些重要性质.     

保等价部分变换半群的变种半群上的正则元

在现有的保等价部分变换半群的基础上,引入了一个新的运算,得出保等价部分变换半群的变种半群的概念,利用格林关系及幂等元的正则性,讨论了这类半群中元素的正则性,给出了保等价部分变换半群的变种半群中一个元是正则元的充要条件     

完全正则半群的直觉模糊软子半群

将直觉模糊软集运用在完全正则半群上,给出了完全正则半群的直觉模糊软子半群的新概念,研究了它的一些相关性质及若干等价刻画。最后,讨论了完全正则半群的直觉模糊软子半群的同态像与原像的性质。     

П正则半群的幂等元同余类

本文分别给出П正则半群的幂等元同余类和Пｏｒｔｈｏｄｏｘ半群［１］的幂等元同余类的П正则性刻画．其次，证明П逆半群或完全П正则半群Ｓ的幂等元同余类是Ｓ的П正则子半群．最后讨论ｏｒｔｈｏｄｏｘ半群的幂等元同合类的正则性．     

Ⅱ正则半群的幂等元同余类

本文分别给出Ⅱ正则半群的幂等元同余类和Ⅱｏｒｔｈｏｄｏｘ半群的幂等元同余类的Ⅱ正则性刻画，其次，证明Ⅱ逆半群或完全Ⅱ逆半群或完全Ⅱ正则半群Ｓ的幂等元同余类是Ｓ的Ⅱ正则子半群。最后讨论ｏｒｈｔｏｄｏｘ半群的幂等元同余类的正则性。     

Quasiregular and Baer lattices — II

Let L be a compactly generated multiplicative lattice with 1 compact in which every finite product of compact elements is compact and u ∈ L be a radical element. Under this hypothesis, in this paper we extend the concepts such as Baer lattices, quasiregular lattices etc. to what we respectively call Baer lattices w.r.t. u, quasiregular lattices w.r.t. u etc. and using these concepts we extend here the results proved by D. D. Anderson, C. Jayaram and P. A. Phiri. In the course of the development, we add many fruitful concepts and results. Also we study nature and characterizations of different elements.      

A dual-dual mixed formulation for nonlinear exterior transmission problems

We combine a dual-mixed finite element method with a Dirichlet-to-Neumann mapping (derived by the boundary integral equation method) to study the solvability and Galerkin approximations of a class of exterior nonlinear transmission problems in the plane. As a model problem, we consider a nonlinear elliptic equation in divergence form coupled with the Laplace equation in an unbounded region of the plane. Our combined approach leads to what we call a dual-dual mixed variational formulation since the main operator involved has itself a dual-type structure. We establish existence and uniqueness of solution for the continuous and discrete formulations, and provide the corresponding error analysis by using Raviart-Thomas elements. The main tool of our analysis is given by a generalization of the usual Babuska-Brezzi theory to a class of nonlinear variational problems with constraints.

     

Maeda-type Decomposition of CJ-generated Algebraic Lattices

We prove necessary and sufficient conditions for the decomposition of an arbitrary CJ-generated algebraic lattice into a direct product of subdirectly irreducible lattices. We generalize earlier results due to F. Maeda, T. Katriák and the present author. New structure theorems for two classes of CJ-generated algebraic lattices are also obtained.AMS Subject Classification (1991) 06B05 06B10Research partially supported by Hungarian National foundation for Scientific Research, Grant No. T029525 and T030243 and by János Bolyai Grant of Hungarian Academy of Science.     

Superalgebras with superinvolution whose symmetric or skewsymmetric elements are regular

We study semiprime superalgebras with superinvolution whose symmetric elements are not zero divisors, and semiprime superalgebras with superinvolution, with nonzero odd part, whose skewsymmetric elements are not zero divisors. We prove that, in both cases, such superalgebras are a domain or the subdirect sum of a domain and its opposite.     

Linear maps preserving Fredholm and Atkinson elements of C *-algebras

Let A be a unital C*-algebra of real rank zero and B be a unital semisimple complex Banach algebra. We characterize linear maps from A onto B preserving different essential spectral sets and quantities such as the essential spectrum, the (left, right) essential spectrum, the Weyl spectrum, the index and the essential spectral radius.     

A nodal coupling of finite and boundary elements

This article presents and analyzes a simple method for the exterior Laplace equation through the coupling of finite and boundary element methods. The main novelty is the use of a smooth parametric artificial boundary where boundary elements fit without effort together with a straight approximate triangulation in the bounded area, with the coupling done only in nodes. A numerically integrated version of the algorithm is also analyzed. Finally, an isoparametric variant with higher order is proposed. © 2003 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 19: 555–570, 2003     

Uniquely Clean Elements in Rings

It is well known that every uniquely clean ring is strongly clean. In this article, we investigate the question of when this result holds element-wise. We first construct an example showing that uniquely clean elements need not be strongly clean. However, in case every corner ring is clean the uniquely clean elements are strongly clean. Further, we classify the set of uniquely clean elements for various classes of rings, including semiperfect rings, unit-regular rings, and endomorphism rings of continuous modules.     

关于自同构作用下的不变元

文章主要讨论了代数（环）、（双）Ｈｏｐｆ代数中自同构作用下不变元素的性质，得到一些新的结果：设Ａ是有限维半单代数，则ＡｕｔＡ作用下的不变元属于中心，并且举出反例说明这个性质不能一般化到有限维代数、有限维半单（双）Ｈｏｐｆ代数．