Identifying domatic partitions via graph dynamical systems

Abstract

For a graph $G=(V,E),$ a set of vertices $D\subseteq V$ is called a dominating set if every vertex in $V\backslash D$ is adjacent to a vertex in $D.$ A domatic-$2$-partition of $G$ is a partition of its vertices into two disjoint dominating sets. In this paper, for a finite simple connected graph $G,$ we construct a graph dynamical system $F$ and show that the set of dominating sets of $G$ are in one-to-one correspondence with the image of the action map of $F$. Moreover, we obtain the set of all domatic-$2$-partitions of $G$ from the set of all periodic orbits of $F.$ Finally, we extended actions of two dynamical systems to an action of a free semigroup on two letters, and determine independent dominating sets and idomatic partitions using its maximal invariant subset with a reversible action.

12pages. Title changed according to the changing focus. New auxiliary results added