A maximum clique of a graph is a clique (i.e., a complete subgraph) of maximum possible size for
. Some authors refer to maximum cliques simply as "cliques." The size of a maximum clique is the clique
number. Computing this size is an NP-hard problem;
the decision problem of whether a graph contains a clique
of size at least
is an NP-complete problem (Skiena 1997).
A maximum clique in a given graph can be found in the Wolfram
Language using FindClique[g][[1]].
The command Sort[FindClique[g,
Length /@ FindClique[g], All]] will find all maximum
cliques.
A complete k-partite graph with nonempty parts has maximum clique size
. A graph on
vertices
having the maximum possible edge count among those
that do not contain the complete graph
as a subgraph is called the
Turán's graph
(Gross and Yellen 2006, pp. 476-477; note the
slightly nonstandard indexing
by Skiena 1990, p. 218 and Pemmaraju and Skiena
2003, pp. 247-248).