关于图B（m,n,p）的优美性

在［１］［２］中已证明“除去三种特殊情形，连结两个顶点的三条独立路所成简单图Ｂ（ｍ，ｎ，ｐ）是优美图”，并猜想：对除去的三种情形，Ｂ（ｍ，ｎ，ｐ）也是优美的。本文证实了上术猜想。这样一来，也就证明了［３］中的猜想：有－ｈ－链弦的圈是优美的（ｈ≥２）。     

On the Maximum Spectral Radius of （m, n）-trees with Given Diameter

Let (V, U) be the vertex-partition of tree T as a bipartite graph. T is called an (m,n)-tree if |V|=m and |U| = n. For given positive integers m,n and d, the maximum spectral radius of all (m,n)-trees on diameter d are obtained, and all extreme graphs are determined.     

A Note on L（2, 1）-labelling of Trees

An L(2,1)-labelling of a graph G is a function from the vertex set V (G) to the set of all nonnegative integers such that |f(u) f(v)| ≥ 2 if d G (u,v)=1 and |f(u) f(v)| ≥ 1 if d G (u,v)=2.The L(2,1)-labelling problem is to find the smallest number,denoted by λ(G),such that there exists an L(2,1)-labelling function with no label greater than it.In this paper,we study this problem for trees.Our results improve the result of Wang [The L(2,1)-labelling of trees,Discrete Appl.Math.154 (2006) 598-603].     

Gorenstein-Projective Modules over T_（m,n）（A）

A new class of Gorenstein algebras T _m,n (A) is introduced, their module categories are described, and all the Gorenstein-projective T _m,n (A)-modules are explicitly determined.     

A Note on the Dimension Theory of ℤ n -Graded Rings

In this note we want to generalize some of the results in [1 Brewer , J. , Montgomery , P. , Rutter E. , Heinzer , W. ( 1973 ). Krull dimension of polynomial rings in “Conference on Commutative Algebra, Lawrence 1972.” . Springer Lecture Notes in Mathematics 311 : 26 – 45 .[Crossref] , [Google Scholar]] from polynomial rings in several indeterminates to arbitrary ? ⁿ -graded commutative rings. We will prove an analogue of Jaffard's Special Chain Theorem and a similar result for the height of a prime ideal 𝔭 over its graded core 𝔭*.     

A Note on Higher Cohomology Groups of Kähler Quotients

Consider a holomorphic $#x2102;^×-action on a possibly noncompact Kähler manifold. We show that the highercohomology groups appearing in the geometric quantization of thesymplectic quotient are isomorphic to the invariant parts of thecorresponding cohomology groups of the original manifold. Fornon-Abelian group actions on compact Kähler manifolds, this resultwas proved recently by Teleman. Our approach is applying the holomorphicinstanton complex to the prequantum line bundles over the symplecticcuts. We also settle a conjecture of Zhang and the present author on theexact sequence of higher cohomology groups in the context of symplecticcutting.     

（mg＋m—1,mf—m＋1）—图的（g,f）—因子

本文证明了（ｍｇ＋ｍ－１,ｍｆ－ｍ＋１）－图具有一些特殊的（ｇ,ｆ）－因子,从而推广到了关于（ｇ,ｆ）－覆盖图和（ｇ,ｆ）－消去图的有关结果,有助于进一步研究（ｍｇ＋ｍ－１,ｍｆ－ｍ＋１）－图的正交因子分解问题。     

RESEARCH ANNOUNCEMENTS——Strong Discreteness of Subgroups of SL（2, Гn）

As in [1,6], let Гn be the n-dimensional Clifford group, i.e., the set of all elements in n-dimensional Clifford algebra An, which can be expressed as a finite product of non-zero-vertors and SL(2, Гn) denote the group of n-dimensional Clifford matrices A=(α b c d)which satisfy:     

SCORE LISTS IN （h, k）-BIPARTITE HYPERTOURNAMENTS

Given non-negative integers m,n,h and k with m ≥ h ＞ 1 and n ≥ k ＞ 1, an (h, k)-bipartite hypertournament on m n vertices is a triple (U, V, A), where U and V are two sets of vertices with |U| = m and |V| = n, and A is a set of (h k)-tuples of vertices,called arcs, with at most h vertices from U and at most k vertices from V, such that for any h k subsets U1 ∪ V1 of U ∪ V, A contains exactly one of the (h k)! (h k)-tuples whose entries belong to U1 ∪ V1. Necessary and sufficient conditions for a pair of non-decreasing sequences of non-negative integers to be the losing score lists or score lists of some(h, k)-bipartite hypertournament are obtained.     

Nonsingularity on Level—2（r1,r2）—circulant Matrices of Type（m,n）

ＮｏｎｓｉｎｇｕｌａｒｉｔｙｏｎＬｅｖｅｌ－２（ｒ_１，ｒ_２）－ｃｉｒｃｕｌａｎｔＭａｔｒｉｃｅｓｏｆＴｙｐｅ（ｍ，ｎ）ＪｉａｎｇＺｈａｏｌｉｎ（江兆林）（Ｄｅｐｔ．ｏｆＭａｔｈ．，ＬｉｎｙｉＴｅａｃｈｅｒ＇ｓＣｏｌｌｅｇｅ，Ｓｈａｎｄｏｎｇ，Ｌｉｎ...     

完全图的广义Mycielski图的邻强边染色

对|V(G)|≥3的连通图G,若κ-正常边染色法满足相邻点的色集合不相同,则称该染色法为κ-邻强边染色,其最小的κ称为图G的邻强边色数。张忠辅等学者猜想:对|V(G)|≥3的连通图G,G≠C_5其邻强边色数至多为△(G)+2,利用组合分析的方法给出了完全图的广义Mycielski图的邻强边色数,从而验证了图的邻强边染色猜想对于此类图成立。     

一类3-正则图的邻强边染色

对简单图G(V,E),f是从V(G)∪E(G)到{1,2,…,k}的映射,k是自然数,若f满足(1)uv,uw∈E(G),u≠w,f(uv)≠f(uw);(2)uv∈E(G),C(u)≠C(v).则称f是G的一个邻强边染色,最小的k称为邻强边色数,其中C(u)={f(uv)|uv∈E(G)}.给出了一类3-正则重圈图的邻强边色数.     

图的邻点可区别无圈边染色的一个界

图G的一个正常边染色被称作邻点可区别无圈边染色,如果G中无二色圈,且相邻点关联边的色集合不同.应用概率的方法得到了图G的一个邻点可区别无圈边色数的上界,其中图G为无孤立边的图.     

图的Smarandachely邻点边色数的界

对图G的一个k-正常变染色法f,若图G中任意相邻两点的相邻边色集合互相不包含,那么称f为图G的一个k-Smarandachely邻点边染色(简记为k-SEC),而最小的正整数k称为图G的Smarandachely邻点边色数.尝试应用Lovasz局部引理来得到了Smarandachely邻点边色数的上界.     

关于图的点可区别边染色猜想的一点注

图G的一个k-正常边染色f被称为点可区别的是指任意两点的点及其关联边所染色集合不同,所用最少颜色数被称为G的点可区别边色数,张忠辅教授提出一个猜想即对每一个正整数k≥3,总存在一个最大度为△(G)=k≥3的图G,图G一定有一个子图H,使得G的点可区别的边色数不超过子图的.本文证明了对于最大度△≤6时,猜想正确.     

关于图K_(2n)-E(C_4)的点可区别边色数

图G的一个k-正常边染色f被称为点可区别边染色是指任何两点的点及其关联边的色集合不同,所用最小的正整数k被称为G的点可区别边色数,记为x′_(vd)(G).用K_(2n)-E(C_4)表示2n阶完全图删去其中一条4阶路的边后得到的图,文中得到了K_(2n)-E(_4)的点可区别边色数.     

扇的倍图的邻点可区别边色数

设G(V,E)是阶数至少是3的简单连通图,若f是图G的k-正常边染色,使得对任意的uv∈E(G),C(u)≠C(v),那么称f是图G的k-邻点可区别边染色(k-ASEC),其中C(u)={f(uw)│uw∈E(G)},而χa′s(G)=min{k│存在G的一个k-ASEC},称为G的邻点可区别边色数.本文给出扇的倍图D(Fm)的邻点可区别边色数.     

完全二部图的广义Mycielski图的全染色与边染色

为了找到Km,n图的广义Mycielski图的全色数与边色数,用分析的方法,考虑不同情况,给出了它的全染色法与边染色法,得到了它的全色数与边色数.     

关于Sm∨Sn的边色数和邻强边色数

本文研究了m＋1阶的星Sm和n＋1阶的星Sn的联图Sm∨Sn的边染色和邻强边染色．得到了Sm∨Sn的边色数和邻强边色数。     

关于图P_n~k的均匀染色

对简单图G=〈V,E〉及自然数k,令V(Gk) =V(G) ,E(Gk) =E(G)∪{uv|d(u,v) =k},其中d(u,v)表示G中u,v的距离,称图Gk为G的k方图.本文讨论了路的k方图Pkn的均匀点染色、均匀边染色和均匀邻强边染色,利用图的色数的基本性质和构造染色函数的方法,得到相应的色数χev(Pkn) ,χ′ee(Pkn) ,χ′eas(Pkn) .并证明猜想“若图G有m -EASC,则一定有m +1 -EASC”对Pkn是正确的.