Chromatic polynomials,polygon trees,and outerplanar graphs

It is proved that all classes of polygon trees are characterized by their chromatic polynomials, and a characterization is given of those polynominals that are chromatic polynomials of outerplanar graphs. The first result yields an alternative proof that outerplanar graphs are recognizable from their vertex-deleted subgraphs. © 1929 John Wiley & Sons, Inc.