图的顶点个数与完美对集及色数间的关系和应用

本文从另一角度一顶点个数来研究完美对集及图的色数之间的关系及应用，通过对特殊图形；偶图，完全图的研究，最终推导出一般情况下图的顶点个数与完美对集及色数问的关系及一些实际问题的应用。     

Finding all efficient extreme points for multiple objective linear programs

In this paper we develop a method for finding all efficient extreme points for multiple objective linear programs. Simple characterizations of the efficiency of an edge incident to a nondegenerate or a degenerate efficient vertex are given. These characterizations form the basis of an algorithm for enumerating all efficient vertices. The algorithm appears to have definite computational advantages over other methods. Some illustrative examples are included.     

Generalized Green Correspondence of Graded Modules

The author studies the Green correspondence and quasi-Green correspondence for indecomposable modules over strongly graded rings. The motivation is to investigate the influence of induction and restriction processes on indecomposability of graded modules.     

On the vertices of the -additive core

The core of a game v on N, which is the set of additive games φ dominating v such that φ(N)=v(N), is a central notion in cooperative game theory, decision making and in combinatorics, where it is related to submodular functions, matroids and the greedy algorithm. In many cases however, the core is empty, and alternative solutions have to be found. We define the k-additive core by replacing additive games by k-additive games in the definition of the core, where k-additive games are those games whose Möbius transform vanishes for subsets of more than k elements. For a sufficiently high value of k, the k-additive core is nonempty, and is a convex closed polyhedron. Our aim is to establish results similar to the classical results of Shapley and Ichiishi on the core of convex games (corresponds to Edmonds’ theorem for the greedy algorithm), which characterize the vertices of the core.     

低度平面图的边面全色数

平面图G(V,E,F)的边面全色数X,(G)是使得集合E(G)∪ F(G)中相邻和相关联的元素均染为不同颜色的最少颜色数。本文提出猜想:对任何平面图G,有△(G)≤X,(G)≤△(G)+3;并对顶点度不超过3或面度均为3的平面图证明了这个猜想为真。     

The Zariski Topology-Graph of Modules Over Commutative Rings

Let M be a module over a commutative ring, and let Spec(M) be the collection of all prime submodules of M. We topologize Spec(M) with Zariski topology, which is analogous to that for Spec(R), and for a nonempty subset T of Spec(M), we introduce a new graph G(τ _T ), called the Zariski topology-graph. This graph helps us to study the algebraic (resp. topological) properties of M (resp. Spec(M)) by using the graph theoretical tools.     

Least distance methods for the scheme of polytopes

Methods are described and APL-codes are supplied to find vertices, edges, other faces and facets of polytopes given by point sets. The basic subroutine is a simplicial decomposition version of least distance, i.e. quadratic, programming. Computational experience indicates high efficiency.     

On the Vertices of Simple Modules for Symmetric Groups

In this article, we are concerned with the computation of vertices of some series of simple modules for the symmetric group of n letters in odd characteristic. In the first, the second, and the third section of this work we recall some more or less general results that are needed in our proofs. The fourth section contains new ingredients (in terms of dimension) that play an important role in our proofs of the main results in the last section.     

Gauge bosons at zero and finite temperature

Gauge theories of the Yang–Mills type are the single most important building block of the standard model of particle physics and beyond. They are an integral part of the strong and weak interactions, and in their Abelian version of electromagnetism. Since Yang–Mills theories are gauge theories their elementary particles, the gauge bosons, cannot be described without fixing a gauge. Therefore, to obtain their properties a quantized and gauge-fixed setting is necessary.     

Master corner polyhedron: Vertices

We focus on the vertices of the master corner polyhedron (MCP), a fundamental object in the theory of integer linear programming. We introduce two combinatorial operations that transform vertices to their neighbors. This implies that each MCP can be defined by the initial vertices regarding these operations; we call them support vertices. We prove that the class of support vertices of all MCPs over a group is invariant under automorphisms of this group and describe MCP vertex bases. Among other results, we characterize its irreducible points, establish relations between a vertex and the nontrivial facets that pass through it, and prove that this polyhedron is of diameter 2.