A characterization of diameter-2-critical graphs with no antihole of length four
نویسندگان
چکیده
A graph G is diameter-2-critical if its diameter is two and the deletion of any edge increases the diameter. In this paper we characterize the diameter-2-critical graphs with no antihole of length four, that is, the diameter-2-critical graphs whose complements have no induced 4-cycle. Murty and Simon conjectured that the number of edges in a diameter-2-critical graph of order n is at most n2/4 and that the extremal graphs are complete bipartite graphs with equal size partite sets. As a consequence of our characterization, we prove the Murty–Simon Conjecture for graphs with no antihole of length four. MSC: 05C12, 05C35, 05C69
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