An upper bound on the size of a largest clique in a graph
Dennis P. Geoffroy, David P. Sumner · Journal of Graph Theory · 1978
Abstract A graph is point determining if distinct vertices have distinct neighborhoods. The nucleus of a point‐determining graph is the set GO of all vertices, v, such that G–v is point determining. In this paper we show that the size, ω(G), of a maximum clique in G satisfies ω(G) ⩽ 2|π (G)O|, where π(G) (the point determinant of G) is obtained from G by identifying vertices which have the same neighborhood.