In 1996 Kouider and Lonc proved the following natural generalization of Dirac’s Theorem: for any integer k > 2, if G is an n-vertex graph with minimum degree at least n/k, then there are k − 1 cycles in G that together cover all the vertices. This is tight in the sense that there are n-vertex graphs that have minimum degree n/k − 1 and that do not contain k − 1 cycles with this property. A conc...

PURPOSE The purpose of this study was to evaluate, in situ, the initial adhesion of microorganisms to as well as the surface roughness and chemical composition of ProBase Hot (Ivoclar Vivadent), a hard acrylic resin, and Vertex Soft (Vertex-Dental), an acrylic-based soft liner, used in removable dental prostheses. MATERIALS AND METHODS Equal sized disks of ProBase Hot and Vertex Soft were pre...

we present a matching and lp based heuristic algorithm that decides graph non-hamiltonicity. each of the n! hamilton cycles in a complete directed graph on n + 1 vertices corresponds with each of the n! n-permutation matrices p, such that pu,i = 1 if and only if the ith arc in a cycle enters vertex u, starting and ending at vertex n + 1. a graph instance (g) is initially coded as exclusion set ...

Let G be a 4-connected graph. For an edge e of G, we do the following operations on G: first, delete the edge e from G, resulting the graph G e; second, for all vertices x of degree 3 in G e, delete x from G e and then completely connect the 3 neighbors of x by a triangle. If multiple edges occur, we use single edges to replace them. The final resultant graph is denoted by G e. If G e is 4-conn...

We investigate minimum vertex degree conditions for 3-uniform hypergraphs which ensure the existence of loose Hamilton cycles. A loose Hamilton cycle is a spanning cycle in which consecutive edges intersect in a single vertex. We prove that every 3-uniform n-vertex (n even) hypergraph H with minimum vertex degree δ1(H) ≥ ( 7 16 + o(1) ) (n 2 ) contains a loose Hamilton cycle. This bound is asym...

Increased life span of humans and dynamic development of prosthetic treatment has caused that increased number of people are using removable dentures for longer periods of time. The materials used to make those prosthesis are becoming a potential pathogen factor for oral mucosa being in contact with this material. Prosthetic stomatopathy occurs in 20% to 70% of the patients who are using remova...

We investigate minimum vertex degree conditions for 3-uniform hypergraphs which ensure the existence of loose Hamilton cycles. A loose Hamilton cycle is a spanning cycle in which consecutive edges intersect in a single vertex. We prove that every 3-uniform n-vertex (n even) hypergraph H with minimum vertex degree δ1(H) ≥ ( 7 16 + o(1) ) ( n 2 ) contains a loose Hamilton cycle. This bound is asy...

A cycle packing in a (directed) multigraph is a vertex disjoint collection of (directed) elementary cycles. If D is a demiregular multidigraph we show that the arcs of D can be partitioned into Ai. cycle packings where Ain is the maximum indegree of a vertex in D. We then show that the maximum length cycle packings in any digraph contain a common vertex.