A graph G is said to be 4-ordered if for any ordered set of four distinct vertices of G, there exists a cycle in G that contains all of the four vertices in the designated order. Furthermore, if we can find such a cycle as a Hamiltonian cycle, G is said to be 4-ordered Hamiltonian. It was shown that every 4-connected planar triangulation is (i) Hamiltonian (by Whitney) and (ii) 4-ordered (by Go...

A substantial amount of research in graph theory continues to concentrate on the existence of hamiltonian cycles and perfect matchings. A classic theorem of Dirac states that a sufficient condition for an n-vertex graph to be hamiltonian, and thus, for n even, to have a perfect matching, is that the minimum degree is at least n/2. Moreover, there are obvious counterexamples showing that this is...

A graph G is said to be 4-ordered if for any ordered set of four distinct vertices of G, there exists a cycle in G that contains all of the four vertices in the designated order. Furthermore, if we can find such a cycle as a Hamiltonian cycle, G is said to be 4-ordered Hamiltonian. It was shown that every 4-connected planar triangulation is (i) Hamiltonian (by Whitney) and (ii) 4-ordered (by Go...

The k-ary n-cubes, Qn, is one of the most well-known interconnection networks in parallel computers. Let n ≥ 1 be an integer and k ≥ 3 be an odd integer. It has been shown that any Qn is a 2n-regular, vertex symmetric and edge symmetric graph with a hamiltonian cycle. In this article, we prove that any k-ary n-cube contains 2n mutually independent hamiltonian cycles. More specifically, let vi ∈...

Let G be a k-regular 2-connected graph of order n. Jackson proved that G is hamiltonian if n 5 3k. Zhu and Li showed that the upper bound 3k on n can be relaxed to q k if G is 3-connected and k 2 63. We improve both results by showing that G is hamiltonian if n 5 gk 7 and G does not belong to a restricted class 3 of nonhamiltonian graphs of connectivity 2. To establish this result we obtain a v...

We consider the fair Hamiltonian cycle Maker-Breaker game, played on the edge set of the complete graph Kn on n vertices. It is known that Maker wins this game if n is sufficiently large. We are interested in the minimum number of moves needed for Maker in order to win the Hamiltonian cycle game, and in the smallest n for which Maker has a winning strategy for this game. We prove the following ...

Let G be a connected graph on n vertices, and let ; ; and be edge-disjoint cycles in G such that (i) ; (resp. ;) are vertex-disjoint and (ii) jj + jj = jj+ jj = n, where jj denotes the length of. We say that ; ; and yield two edge-disjoint hamiltonian cycles by edge exchanges if the four cycles respectively contain edges e; f; g and h such that each of (? feg) S (? ffg) S fg; hg and (? fgg) S (...