Pentagonal 3-polytopal graphs with edges of only two types and shortness parameters Original Research Article

We consider the class of pentagonal 3-polytopal graphs all of whose edges are incident either with two 3-valent vertices or with a 3-valent vertex and a q-valent vertex. For most values of q, (i) we find a small non-hamiltonian graph in the class and (ii) we show that the shortness exponent of the class and the shortness coefficient of a special subclass are less than one. For q=4, we find a positive lower bound for the shortness coefficient.