4一致反超图的最小边数问题

混合超图是在超图的基础上添加一个反超边得到的图．超边和反超边的区别主要体现在着色要求上．在着色中,要求每一超边至少要有两个点着不同的颜色,而每一反超边至少有两个点着相同的颜色．最大最小颜色数分别称为混合超图的上色数和下色数。本文主要研究反超图,即只含反超边的超图。讨论了上色数为3的4一致超图的最小边数问题．给出了上色数为3的4一致反超图的最小边数的一个上界和一个下界．     

反超图的笛卡儿积的上色数

讨论反超图的笛卡儿积的着色理论 ,求出了满足一定条件的反超图的笛卡儿积的上色数 .     

图的最大亏格与2-因子

图Ｇ的一个２因子Ｆ就是Ｇ的这样一个支撑子图，使其任何节点ｖ∈Ｖ的次ｄＦ（ｖ）＝２．易见，Ｇ的每个２因子均为无公共节点的圈之并．若Ｆ的每个圈的长均为３（或４），则称Ｇ含有一个三角形（或四边形）２因子．Ｍ．ｋ∨ｏｖｉｅｒａ［５］得到了含有三角形２因子的３－正则图的最大亏格．本文在３－正则图上，引进了扩张运算和讨论了与最大亏格和Ｂｅｔｉ亏数之间的关系．利用这些运算，得到了所有含四边形２因子的连通３－正则图是上可嵌入的，即γＭ（Ｇ）＝ｎ４（ｎ为Ｇ的节点数ｎ＝｜Ｖ（Ｇ）｜）．然后，基于此证明了含四边形２因子且所有节点ｖ∈Ｖ的次ｄＧ（ｖ）＝３（ｍｏｄ４）的图Ｇ均为上可嵌入的     

复合图的1－因子分解

本文研究了复合图１－因子分解问题，给出了复合图可１－因子分解的几个充分条件．设图Ｇ和Ｈ都是正则因，那么Ｇ和Ｈ的复合图Ｇ［Ｈ］可１－因子分解，如果Ｇ和Ｈ满足下列三个条件之一：（１）Ｇ可１－因子分解；（２）Ｇ至少有　１－因子，Ｈ为偶阶正则图［Ｖ（Ｈ）｜≥２；（３）Ｇ可以分解为一些１－因子和２－因子之并，Ｈ为偶阶正则图且至少有ｍａｘ｛０，△（Ｈ）－４｝个１－因子．     

强正则图的一些性质

文[3]给出了强正则图的概念及有关性质,本文在此基地上利用图的谱性质,得到了强正则图的又一些性质。     

三度边正则图的三个无限族

图X称为边正则图，若X的自同构群Aut(X)在X的边集上的作用是正则的．本文考察了三度边正则图与四度Cayley图的关系，给出了一个由四度Cayley图构造三度边正则图的方法，并且构造了边正则图的三个无限族．     

6度1-正则Cayley图

试图对6度1-正则Cayley图给一个完全分类．利用无核的概念将图自同构群归结到对称群S6的子群．然后根据1-正则图的性质构造出所有可能的具有非交换点稳定子群的无核6度1-正则Cayley图,进一步证明了构造出的图都是有核的,由此给出了这一类图的一个完全分类．     

关于{P2, Ci| i≥3}-覆盖图

设 Ｇ是一个图,若对于 Ｇ的任意一边 Ｇ都有｛Ｐ_２,Ｃｉ｜ｉ－＞３｝－因子含有这条边,则称Ｇ是｛Ｐ_２,Ｃｉ｜ｉ－＞３｝－覆盖图．本文给出连通非二分图Ｇ是｛Ｐ２,Ｃｉ｜ｉ－＞３｝－覆盖图的充要条件为任给Ｓ■Ｖ（Ｇ）,Ｖ（Ｇ）≠Ｓ≠■有ｉ（Ｇ－Ｓ）＿＞｜Ｓ｜－１成立．     

一类变换图的连通性

本文定义了一类由给定的一个３－正则平面偶图的全体完美匹配所构成的变换图，并证明了该变换图是连通的．由此可得出结论：从任一给定的３－正则平面偶图的完美匹配出发，通过一种所谓的旋转运算，就可以生成全部其它的完美匹配．     

图的完全正则自同态

作为图的代数分析的一部分，对图的自同态幺半群的研究近年来有一定的进展（参见［３］及［４］）。这类研究的主要目的在于将半群理论应用于图论。文献［５］研究了图的正则自同态及其逆。在此基础上本文进一步描述了图的完全正则自同态的组合特征；同时对含有完全正则自同态ｆ的极大子群，文中也明确给出了其单位元素及ｆ的逆     

Completely reducible Lie subalgebras

Let G be a connected and reductive group over the algebraically closed field K. J-P. Serre has introduced the notion of a G-completely reducible subgroup H ⊂ G. In this paper, we give a notion of G-complete reducibility—G-cr for short—for Lie subalgebras of Lie(G), and we show that if the closed subgroup H ⊂ G is G-cr, then Lie(H) is G-cr as well.     

Cleft extensions in braided categories

Majid in [14] and Bespalov in [2] obtain a braided interpretation of Radford’s theorem about Hopf algebras with projection ([19]). In this paper we introduce the notion of H-cleft comodule (module) algebras (coalgebras) for a Hopf algebra H in a braided monoidal category, and we characterize it as crossed products (coproducts). This allows us give very short proofs for know results in our context, and to introduce others stated for the category of R-modules about of Hopf algebra extensions. In particular we give a proof of the result by Bespalov [2] for a braided monoidal category with co(equalizers).     

A Non-existence problemn for degenerate elliptic pde's

We consider a non-linear subelliptic problem in a bounded open set of Rⁿ. We give a very weak notion of solution and we prove a non-existence result for the problem. This result generalizes the analogous elliptic case already considered by H. Brezis and X. Cabré     

A New by the Characterization of Mobius Transformations Use of Apollonius Points of （2n-1）-gons

In this paper, we give a new characterization of Mobius transformations. To do this, we extend the notion of Apollonius points of a triangle and of a pentagon, to the notion of Apollonius points of an arbitrary （2n-1）-gon.     

Tilting subcategories in extriangulated categories

Extriangulated category was introduced by H.Nakaoka and Y.Palu to give a unification of properties in exact categories anjd triangulated categories.A notion of tilting(resp.,cotilting)subcategories in an extriangulated category is defined in this paper.We give a Bazzoni characterization of tilting(resp.,cotilting)subcategories and obtain an Auslander-Reiten correspondence between tilting(resp.,cotilting)subcategories and coresolving covariantly(resp.,resolving contravariantly)finite subcatgories which are closed under direct summands and satisfy some cogenerating(resp.,generating)conditions.Applications of the results are given:we show that tilting(resp.,cotilting)subcategories defined here unify many previous works about tilting modules(subcategories)in module categories of Artin algebras and in abelian categories admitting a cotorsion triples;we also show that the results work for the triangulated categories with a proper class of triangles introduced by A.Beligiannis.     

On the generalized derivations of bimodules

Recently, we introduced the notion of a generalized derivation from a bimodule to a bimodule. In this paper, we give a more general notion based on commutators which covers generalized derivations as a special case. Using it, we show that the separability of an algebra extension is characterized by generalized derivations.     

Well-setness and scalarization in set optimization

In this paper, we consider a notion of global well-setness for a set optimization problem using the excess function. We give sufficient conditions for well-setness and establish Dontchev–Zolezzi type measure for well-setness. Moreover, we relate this notion with well-setness notion for a scalar problem obtained by using generalized Gerstewitz’s function.     

Self-dual weak Hopf algebras

In this paper, we define the notion of self-dual graded weak Hopf algebra and self-dual semilattice graded weak Hopf algebra. We give characterization of finite-dimensional such algebras when they are in structually simple forms in the sense of E. L. Green and E. N. Morcos. We also give the definition of self-dual weak Hopf quiver and apply these types of quivers to classify the finite- dimensional self-dual semilattice graded weak Hopf algebras. Finally, we prove partially the conjecture given by N. Andruskiewitsch and H.-J. Schneider in the case of finite-dimensional pointed semilattice graded weak Hopf algebra H when grH is self-dual.     

A new lower bound on the strong connectivity of an oriented graph. Application to diameters with a particular case related to Caccetta Häggkvist conjecture

In this paper, by using minimum out-degree and minimum in-degree, we give a new lower bound on the vertex-strong connectivity of an oriented graph. In the case of a tournament, our lower bound improves that of Thomassen obtained in 1980 and which use the notion of irregularity (see [C. Thomassen, Hamiltonian-connected tournaments, J. Combin. Theory Ser. B 28 (1980) 142–163]). As application, we determine a pertinent upper bound on the diameter of some oriented graphs, and in a particular case, related to Caccetta Häggkvist conjecture, we improve a result of Broersma and Li obtained in 2002 (see [H.J. Broersma, X. Li, Some approaches to a conjecture on short cycles in digraphs, Discrete Appl. Math. 120 (2002) 45–53]).     

The notion of exhaustiveness and Ascoli-type theorems

In this paper we introduce the notion of exhaustiveness which applies for both families and nets of functions. This new notion is close to equicontinuity and describes the relation between pointwise convergence for functions and -convergence (continuous convergence). Using these results we obtain some Ascoli-type theorems dealing with exhaustiveness instead of equicontinuity. Also we deal with the corresponding notions of separate exhaustiveness and separate -convergence. Finally we give conditions under which the pointwise limit of a sequence of arbitrary functions is a continuous function.