clique
A maximal http://planetmath.org/node/1757complete subgraph
of a graph is a clique, and the clique number
of a graph is the \\PMlinkescapephrasemaximal order
maximal order of a clique in . Simply, is the maximal order of a subgraph of . Some authors however define a clique as any subgraph of and refer to the other definition as maximum clique.
Adapted with permission of the author from by Béla Bollobás, published by Springer-Verlag New York, Inc., 1998.