Chromaticity of two‐trees
Earl Glen Whitehead · Journal of Graph Theory · 1985
Abstract The graphs called 2‐trees are defined by recursion. The smallest 2‐tree is the complete graph on 2 vertices. A 2‐tree on n + 1 vertices (where n ≥ 2) is obtained by adding a new vertex adjacent to each of 2 arbitrarily selected adjacent vertices in a 2‐tree on n vertices. A graph G is a 2‐tree on n(≥2) vertices if and only if its chromatic polynomial is equal to γ(γ ‐ 1)(γ ‐ 2)n—2.