Displaying similar documents to “Locally C n k graphs.”

The perfection and recognition of bull-reducible Berge graphs

Hazel Everett, Celina M. H. de Figueiredo, Sulamita Klein, Bruce Reed (2005)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

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The recently announced Strong Perfect Graph Theorem states that the class of perfect graphs coincides with the class of graphs containing no induced odd cycle of length at least 5 or the complement of such a cycle. A graph in this second class is called Berge. A bull is a graph with five vertices x , a , b , c , d and five edges x a , x b , a b , a d , b c . A graph is bull-reducible if no vertex is in two bulls. In this paper we give a simple proof that every bull-reducible Berge graph is perfect. Although this result follows...