A graph of order n is said to be pancyclic if it contains cycles of all lengths from three to n. Let G be a hamiltonian graph and let x and y be vertices of G that are consecutive on some hamiltonian cycle in G. Hakimi and Schmeichel showed [2] that if d(x)+d(y) n then either G is pancyclic, G has cycles of all lengths except n - 1 or G is isomorphic to a complete bipartite graph. In this paper, we study the existence of cycles of various lengths in a hamiltonian graph G given the existence of a pair of vertices that have a high degree sum but are not adjacent on any hamiltonian cycle in G. Keywords hamiltonian cycle
Michael Ferrara, Michael S. Jacobson, Angela Harri