{ "id": "math/9912234", "version": "v1", "published": "1999-12-30T20:18:33.000Z", "updated": "1999-12-30T20:18:33.000Z", "title": "On $α$-Square-Stable Graphs", "authors": [ "Vadim E. Levit", "Eugen Mandrescu" ], "comment": "13 pages, 6 figures", "categories": [ "math.CO" ], "abstract": "The stability number of a graph G, denoted by alpha(G), is the cardinality of a maximum stable set, and mu(G) is the cardinality of a maximum matching in G. If alpha(G) + mu(G) equals its order, then G is a Koenig-Egervary graph. We call G an $\\alpha $-square-stable graph, shortly square-stable, if alpha(G) = alpha(G*G), where G*G denotes the second power of G. These graphs were first investigated by Randerath and Wolkmann. In this paper we obtain several new characterizations of square-stable graphs. We also show that G is an square-stable Koenig-Egervary graph if and only if it has a perfect matching consisting of pendant edges. Moreover, we find that well-covered trees are exactly square-stable trees. To verify this result we give a new proof of one Ravindra's theorem describing well-covered trees.", "revisions": [ { "version": "v1", "updated": "1999-12-30T20:18:33.000Z" } ], "analyses": { "subjects": [ "05C75", "05C69", "05C05", "05C70" ], "keywords": [ "square-stable graph", "ravindras theorem describing well-covered trees", "pendant edges", "cardinality", "second power" ], "note": { "typesetting": "TeX", "pages": 13, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "1999math.....12234L" } } }