A Characterisation of Well-Covered Cubic Graphs

S. R. Campbell1, M. N. Ellingham2, Gordon F. Royle3
1Department of Mathematics and Computer Science Belmont University, 1900 Belmont Blvd Nashville, Tennessee 37212, U.S.A.
2Department of Mathematics, 1326 Stevenson Center Vanderbilt University, Nashville, Tennessee 37240, U.S.A.
3Department of Computer Science, University of Western Australia Nedlands, Western Australia 6009, Australia

Abstract

A graph is said to be \({well-covered}\) if all maximal independent sets of vertices in the graph have the same cardinality. Determining whether a graph is well-covered has recently been shown (independently by Chvátal and Slater and by Sankaranarayana and Stewart) to be a co-NP-complete problem. In this paper, we characterise all well-covered cubic (\(3\)-regular) graphs. Our characterisation yields a polynomial time algorithm for recognising well-covered cubic graphs.