The boundary-edges code for a benzenoid H is defined as the lexicographically maximum code obtained travelling around the boundary of H and noting the number of edges of each successive hexagon traveled. This code is extended to the class of all planar polyhexes by allowing in case of multiple-connectedness to travel from the boundary to each hole and around this hole. Its length is compared to that of other codes for benzenoids. It is then shown how the boundary-edges code can be used to find easily if a polyhex H is simply connected, cata-condensed, branched, has an equal number of peaks and valleys or has some symmetry.
Published July 1994 , 21 pages