Co-intersection graph of submodules of a module

Abstract

Let M be a unitary left R-module where R is a ring with identity. The co-intersection graph of proper submodules of M, denoted by Ω(M), is an undirected simple graph whose the vertex set V(Ω) is a set of all non-trivial submodules of M and there is an edge between two distinct vertices N and K if and only if N+K≠M. In this paper we investigate connections between the graph-theoretic properties of Ω(M) and some algebraic properties of modules . We characterize all of modules for which the co-intersection graph of submodules is connected. Also the diameter and the girth of Ω(M) are determined. We study the clique number and the chromatic number of Ω(M).