Tutte polynomial

Summary

The Tutte polynomial $T(x, y)$ is a polynomial in two variables attached to a graph or, more generally, to a matroid. It is the most general invariant that satisfies the deletion–contraction recurrence, and many counting invariants are specializations of it. Among them are the number of spanning trees, the chromatic polynomial, the flow polynomial and the reliability polynomial. The partition function of the Potts model in statistical physics is another specialization.