截集形式的模糊粗糙集及其性质

用模糊集的截集构造了模糊集的粗糙集,给出了模糊粗糙集的更加严格的数学定义,证明了与文[1]中的等价性,并用新的定义给出模糊粗糙集的相应性质.     

The structure of (theta,pyramid, 1-wheel, 3-wheel)-free graphs

In this paper, we study the class of graphs defined by excluding the following structures as induced subgraphs: theta, pyramid, 1-wheel, and 3-wheel. We describe the structure of graphs in , and we give a polynomial-time recognition algorithm for this class. We also prove that -free graphs in are 4-colorable. We remark that includes the class of chordal graphs, as well as the class of line graphs of triangle-free graphs.     

A Class of Three‐Colorable Triangle‐Free Graphs

The chromatic number of a triangle‐free graph can be arbitrarily large. In this article, we show that if all subdivisions of K_{2, 3} are also excluded as induced subgraphs, then the chromatic number becomes bounded by 3. We give a structural characterization of this class of graphs, from which we derive an coloring algorithm, where n denotes the number of vertices and m the number of edges of the input graph.     

直觉 Fuzzy集的基本定理

提出直觉 Fuzzy集的截集的概念 ,并详细讨论其基本性质 ,在此基础上建立直觉 Fuzzy集的一系列分解定理、表现定理与扩张原理 .