On the Hull Number of the Composition of Graphs

Abstract

The convex hull of a subset $A$ of $V(G)$, where $G$ is a connected graph, is defined as the smallest convex set in $G$ containing $A$. The hull number of $G$ is the cardinality of a smallest set $A$ whose convex hull is $V(G)$. In this paper, we give the hull number of the composition of two connected graphs.