Chromatic polynomial

Chromatic polynomial --- хроматический полином графа.

A chromatic polynomial [math]\displaystyle{ P_{G}(\lambda) }[/math] of a graph [math]\displaystyle{ G }[/math] is the number of good [math]\displaystyle{ \lambda }[/math]-colorings of [math]\displaystyle{ G }[/math] ([math]\displaystyle{ \lambda = 0, 1, \ldots }[/math]). This is a polynomial in [math]\displaystyle{ \lambda }[/math] (for a fixed [math]\displaystyle{ G }[/math]) and so, its definition can be extended to all real (or complex) values of [math]\displaystyle{ \lambda }[/math]. Note that two [math]\displaystyle{ \lambda }[/math]-colorings differing in the labeling of colors are considered as different.