Cocomparability number

Cocomparability number --- число косравнимости.

The cocomparability number of a graph [math]\displaystyle{ G }[/math], denoted [math]\displaystyle{ ccp(G) }[/math], is the smallest integer [math]\displaystyle{ k }[/math] such that [math]\displaystyle{ G }[/math] admits a [math]\displaystyle{ k }[/math]-CCPO (a [math]\displaystyle{ k }[/math]-cocomparability ordering). Note that [math]\displaystyle{ ccp(G) = 1 }[/math] if and only if [math]\displaystyle{ \bar{G} }[/math] (the complement of [math]\displaystyle{ G }[/math]) is a comparability graph.