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Dirac type condition and Hamiltonian graphs

Zhao, Kewen (2011)

Serdica Mathematical Journal

2010 Mathematics Subject Classification: 05C38, 05C45.In 1952, Dirac introduced the degree type condition and proved that if G is a connected graph of order n і 3 such that its minimum degree satisfies d(G) і n/2, then G is Hamiltonian. In this paper we investigate a further condition and prove that if G is a connected graph of order n і 3 such that d(G) і (n-2)/2, then G is Hamiltonian or G belongs to four classes of well-structured exceptional graphs.

Disjoint 5-cycles in a graph

Hong Wang (2012)

Discussiones Mathematicae Graph Theory

We prove that if G is a graph of order 5k and the minimum degree of G is at least 3k then G contains k disjoint cycles of length 5.

Distance independence in graphs

J. Louis Sewell, Peter J. Slater (2011)

Discussiones Mathematicae Graph Theory

For a set D of positive integers, we define a vertex set S ⊆ V(G) to be D-independent if u, v ∈ S implies the distance d(u,v) ∉ D. The D-independence number β D ( G ) is the maximum cardinality of a D-independent set. In particular, the independence number β ( G ) = β 1 ( G ) . Along with general results we consider, in particular, the odd-independence number β O D D ( G ) where ODD = 1,3,5,....

Dominating bipartite subgraphs in graphs

Gábor Bacsó, Danuta Michalak, Zsolt Tuza (2005)

Discussiones Mathematicae Graph Theory

A graph G is hereditarily dominated by a class 𝓓 of connected graphs if each connected induced subgraph of G contains a dominating induced subgraph belonging to 𝓓. In this paper we characterize graphs hereditarily dominated by classes of complete bipartite graphs, stars, connected bipartite graphs, and complete k-partite graphs.

Domination in functigraphs

Linda Eroh, Ralucca Gera, Cong X. Kang, Craig E. Larson, Eunjeong Yi (2012)

Discussiones Mathematicae Graph Theory

Let G₁ and G₂ be disjoint copies of a graph G, and let f:V(G₁) → V(G₂) be a function. Then a functigraph C(G,f) = (V,E) has the vertex set V = V(G₁) ∪ V(G₂) and the edge set E = E(G₁) ∪ E(G₂) ∪ {uv | u ∈ V(G₁), v ∈ V(G₂),v = f(u)}. A functigraph is a generalization of a permutation graph (also known as a generalized prism) in the sense of Chartrand and Harary. In this paper, we study domination in functigraphs. Let γ(G) denote the domination number of G. It is readily seen that γ(G) ≤ γ(C(G,f))...

Domination in generalized Petersen graphs

Bohdan Zelinka (2002)

Czechoslovak Mathematical Journal

Generalized Petersen graphs are certain graphs consisting of one quadratic factor. For these graphs some numerical invariants concerning the domination are studied, namely the domatic number d ( G ) , the total domatic number d t ( G ) and the k -ply domatic number d k ( G ) for k = 2 and k = 3 . Some exact values and some inequalities are stated.

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