HU Zhiquan
Journal of Systems Science and Complexity. 1996, 9(1): 43-049.
Let F be a unique graph with degree sequence(1, 1, 1,3,3, 3). The pendent vertices of F are given by a1, a2 and a3. We say a subgraph H of G satisfies property \phi(u,v) if(N(u) ∩ N(v)) - V(H) ≠ \emptyset. In [1], Broersma and Veldman conjectured that if G is a 2-connected K1,3-be graph and if every induced F of G satisfies (\phi(a1, a2) and \phi(a1, a3)) or (\phi(a1, a2) and \phi(2, Q3)) or (\phi(a1, a3) and \phi(a2, a3)), then G is hamiltonian.In this paper,we show that this conjecture is true. This result generalizes an earlier work of Duffus, Gould and Jacobson. It is (also) applicable to the showing of the hamiltofority of K_{1,3}-free graphs with low edge density and few degrees.