On the essential graph of a poset

Document Type : Original paper

Authors

1 Department of Mathematics, Jundi-Shapur University of Technology, Dezful, Iran

2 Department of Physics, Technical and Vocational University (TVU), Tehran, Iran

Abstract

Let (P,) be an atomic partially ordered set (briefly, a poset) with a minimum element 0, and let I(P) be the set of all nontrivial ideals of P. The essential graph of P, denoted by Ge(P), is an undirected, simple graph with the vertex set I(P) and two distinct vertices I,JI(P) are adjacent in Ge(P) if and only if IJ is an essential ideal of P. We study the connections between the graph-theoretic properties of this graph and the algebraic properties of a poset. We prove that Ge(P) is connected with diameter at most three. Furthermore, all posets are characterized based on the diameters of their essential graphs. Also, all posets with planar Ge(P) are classified. Among other results, the clique number and chromatic number of Ge(P) are determined.

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