Finding Efficient Domination for $(S_{1,2,5},S_{3,3,3}$-Free Chordal Bipartite Graphs in Polynomial Time

TL;DR

This paper proves that the Efficient Domination problem can be solved efficiently in polynomial time for a specific class of chordal bipartite graphs that are free of certain subgraph configurations.

Contribution

It introduces a polynomial-time algorithm for solving ED in $(S_{1,2,5},S_{3,3,3})$-free chordal bipartite graphs, expanding the classes of graphs where ED is tractable.

Findings

ED is polynomial-time solvable for $(S_{1,2,5},S_{3,3,3})$-free chordal bipartite graphs.

The complexity of ED varies with forbidden subgraph classes.

Certain restricted bipartite graph classes admit efficient ED algorithms.

Abstract

A vertex set $D$ in a finite undirected graph $G$ is an {\em efficient dominating set} (\emph{e.d.s.}\ for short) of $G$ if every vertex of $G$ is dominated by exactly one vertex of $D$. The \emph{Efficient Domination} (ED) problem, which asks for the existence of an e.d.s.\ in $G$, is known to be \NP-complete for chordal bipartite graphs as well as for $P_7$-free graphs, and even for very restricted $H$-free bipartite graph classes such as for $K_{1,4}$-free bipartite graphs as well as for $C_4$-free bipartite graphs while it is solvable in polynomial time for $P_8$-free bipartite graphs as well as for $S_{1,3,3}$-free bipartite graphs and for $S_{1,1,5}$-free bipartite graphs. Here we show that ED can be solved in polynomial time for $(S_{1,2,5},S_{3,3,3})$-free chordal bipartite graphs.