L—Fuzzy群的同态与同构及其性质

本文在Ｌ－ｆｕｚｚｙ群的概念的基础上，用集合套概念定义了Ｌ－ｆｕｚｚｙ群间的同态与同构。进而给出了它们的一些性质。最后，我们给出了Ｌ－ｆｕｚｚｙ群的同态基本定理。     

模糊S-拟正规子群及其同态与同构

[1]中给出了模糊S-拟正规子群的一种定义,同时研究了它的一些基本性质。本文利用既约集合套理论提出了模糊S-拟正规子群的另一种定义,并且讨论了上述两种定义的等价性。同时基于本文给出的定义,讨论了模糊S-拟正规子群的一些性质,并讨论了相应的同态与同构性质。     

正则幂环的同态与同构

随着模糊数学的发展,各种代数结构的提升为得越来越重要,李洪兴教授在「１,２」中首次提出并研究了幂群及ＨＸ环,本文在文「３～６」的基础上深入讨论了幂环的一些性质,并在正则幂环中建立了几个同态与同构定理。     

正则HX群的同态与同构

模糊数学的发展突出了集值映射的重要性,各种数学结构需要由论域向其幂集上提升,如序结构的提升,可测结构的提升,拓扑结构的提升等等。文[1]考虑了代数结构的提升问题,首次提出了HX群的概念,随后,文[2]又给出了HX环的定义,本文将在“正则”的条件下,研究HX群中的同态与同构形式。     

L—Fuzzy群的同志和同构

本文研究了Ｌ—Ｆｕｚｚｙ群的同态和同构，给出了它们的一些性质，并把群论中的同态定理和同构定理推广到Ｌ—Ｆｕｚｚｙ群上     

群的模糊同态与模糊商群的同构定理

利用模糊映射,给出群的模糊同态的概念,并得到模糊同态基本定理,同时建立模糊商群的同构定理。     

关于“L—Fuzzy群同态与同构及其性质”一文的注记

文（１）给出了Ｌ－Ｆｕｚｚｙ群间的同态映射，满同态映射以及Ｌ－Ｆｕｚｚｙ群的Ｌ－正规子群等概念。本文指出以上三种定义的不合理性，并给出它们的合理性定义。     

广义同态与算子群

设G1,G2是群,映射f:G1→G2叫作G1到G2的广义同态映射,如果a,b∈G1,等式(ab)f=afbf和(ab)f=bfaf至少有一个成立.利用广义同态映射的概念,本文将算子群的算子集进行扩充,得到一系列有关算子群的结果,从而推广经典的算子群理论.     

一类新无限维李子代数的同构和同态

构造了一类由三个基本元生成的无限维李代数.证明了这类无限维李代数是Virasoro-like李代数的推广.此外,研究了这类李子代数同构和同态.     

On the algorithmic construction of classifying spaces and the isomorphism problem for biautomatic groups

We show that the isomorphism problem is solvable in the class of central extensions of word-hyperbolic groups,and that the isomorphism problem for biautomatic groups reduces to that for biautomatic groups with finite centre.We describe an algorithm that,given an arbitrary finite presentation of an automatic group Γ,will construct explicit finite models for the skeleta of K(Γ,1) and hence compute the integral homology and cohomology of Γ.     

On finite groups with the cayley isomorphism property

Let G be a finite group, and let Cay(G, S) be a Cayley digraph of G. If, for all T ⊂ G, Cay(G, S) ≅ Cay(G, T) implies S^α = T for some α ∈ Aut(G), then Cay(G, S) is called a CI-graph of G. For a group G, if all Cayley digraphs of valency m are CI-graphs, then G is said to have the m-DCI property; if all Cayley graphs of valency m are CI-graphs, then G is said to have the m-CI property. It is shown that every finite group of order greater than 2 has a nontrivial CI-graph, and all finite groups with the m-CI property and with the m-DCI property are characterized for small values of m. A general investigation is made of the structure of Sylow subgroups of finite groups with the m-DCI property and with the m-CI property for large values of m. © 1998 John Wiley & Sons, Inc. J Graph Theory 27: 21–31, 1998     

On the restricted homomorphism problem

The restricted homomorphism problem asks: given an input digraph G and a homomorphism g:G→Y, does there exist a homomorphism f:G→H? We prove that if H is hereditarily hard and YH, then is NP-complete. Since non-bipartite graphs are hereditarily hard, this settles in the affirmative a conjecture of Hell and Nešetřil.     

The restricted isomorphism problem for metacyclic restricted Lie algebras

Let be a restricted Lie algebra with the restricted enveloping algebra over a perfect field of positive characteristic . The restricted isomorphism problem asks what invariants of are determined by . This problem is the analogue of the modular isomorphism problem for finite -groups. Bagiński and Sandling have given a positive answer to the modular isomorphism problem for metacyclic -groups. In this paper, we provide a positive answer to the restricted isomorphism problem in case is metacyclic and -nilpotent.

     

矩阵C*代数上的群作用与*-同构

通过矩阵C^*代数上的不变群作用,给出了决定C^*结构的一个充分条件。     

Graph homomorphism reconfiguration and frozen H-colorings

We say that a graph $F$ strongly arrows a pair of graphs $\left(G,H\right)$ and write $\text{◂→▸}F\stackrel{\text{ind}}{\to }\left(G,H\right)$ if any coloring of its edges with red and blue leads to either a red $G$ or a blue $H$ appearing as induced subgraphs of $F$. The induced Ramsey number, $\text{◂...▸}\text{IR}\left(G,H\right)$, is defined as $\text{◂lim▸}\min \text{◂{}▸}\{|V\left(F\right)|:\text{◂→▸}F\stackrel{\text{ind}}{\to }\left(G,H\right)\}$. We consider the connection between the induced Ramsey number for a pair of two connected graphs $\text{◂...▸}\text{IR}\left(G,H\right)$ and the induced Ramsey number for multiple copies of these graphs $\text{IR}\text{◂()▸}\left(sG,tH\right)$, where $xG$ denotes the pairwise vertex-disjoint union of $x$ copies of $G$. It is easy to see that if $\text{◂→▸}F\stackrel{\text{ind}}{\to }\left(G,H\right)$, then $\text{◂⋅▸}\left(s+t-1\right)F\stackrel{\text{ind}}{\to }\text{◂()▸}\left(sG,tH\right)$. This implies that $$\text{◂...▸}\text{IR}\text{◂≤▸}\text{◂()▸}\left(sG,tH\right)\le \left(s+t-1\right)\text{IR}\left(G,H\right).$$ For several specific graphs, such as a path on three vertices vs a complete multipartite graph, a matching vs a complete graph, or a matching vs another matching, it is known that the above inequality is tight. On the other hand, the inequality is also strict for some graphs. However, even in the simplest case when $H$ is an edge and $t=2$, it is not known for what $G$ and for what $s$ the above inequality is tight. We show that it is tight if $G$ is connected and $s$ is at least as large as the order of $G$. In addition, we make further progress in determining induced Ramsey numbers for multiple copies of graphs, such as paths and triangles.     

Cayley groups

The classical Cayley map, , is a birational isomorphism between the special orthogonal group SO and its Lie algebra , which is SO-equivariant with respect to the conjugating and adjoint actions, respectively. We ask whether or not maps with these properties can be constructed for other algebraic groups. We show that the answer is usually ``no", with a few exceptions. In particular, we show that a Cayley map for the group SL exists if and only if , answering an old question of LUNA.

     

FR^A模的Fuzzy同态的几个重要结果

证明了ＦＲ＾Ａ模的第一同构定理、第二同构定理、同构扩展定理以及其他一些重要性质。