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Subsemi-Eulerian graphs.

Suffel, Charles, Tindell, Ralph, Hoffman, Cynthia, Mandell, Manachem (1982)

International Journal of Mathematics and Mathematical Sciences

Sum of squares of degrees in a graph.

Ábrego, Bernardo M., Fernández-Merchant, Silvia, Neubauer, Michael G., Watkins, William (2009)

JIPAM. Journal of Inequalities in Pure & Applied Mathematics [electronic only]

Sur certaines équations fonctionnelles arithmétiques

Régis de La Bretèche, Gérald Tenenbaum (2000)

Annales de l'institut Fourier

Soit p k le k -ième nombre premier. Une fonction arithmétique complètement additive est définie sur * par la donnée des f ( p k ) et la formule f ( n ) = k 1 f ( p k ) v p k ( n ) ( n 1 ) , où v p désigne la...

The basis number of some special non-planar graphs

Salar Y. Alsardary, Ali A. Ali (2003)

Czechoslovak Mathematical Journal

The basis number of a graph G was defined by Schmeichel to be the least integer h such that G has an h -fold basis for its cycle space. He proved that for m , n 5 , the basis number b ( K m , n ) of the complete bipartite graph K m , n is equal to 4 except for K 6 , 10 , K 5 , n and K 6 , n with n = 5 , 6 , 7 , 8 . We determine the basis number of some particular non-planar graphs such as K 5 , n and K 6 , n , n = 5 , 6 , 7 , 8 , and r -cages for r = 5 , 6 , 7 , 8 , and the Robertson graph.

The cobondage number of a graph

V.R. Kulli, B. Janakiram (1996)

Discussiones Mathematicae Graph Theory

A set D of vertices in a graph G = (V,E) is a dominating set of G if every vertex in V-D is adjacent to some vertex in D. The domination number γ(G) of G is the minimum cardinality of a dominating set. We define the cobondage number b c ( G ) of G to be the minimum cardinality among the sets of edges X ⊆ P₂(V) - E, where P₂(V) = X ⊆ V:|X| = 2 such that γ(G+X) < γ(G). In this paper, the exact values of bc(G) for some standard graphs are found and some bounds are obtained. Also, a Nordhaus-Gaddum type...

The cost chromatic number and hypergraph parameters

Gábor Bacsó, Zsolt Tuza (2006)

Discussiones Mathematicae Graph Theory

In a graph, by definition, the weight of a (proper) coloring with positive integers is the sum of the colors. The chromatic sum is the minimum weight, taken over all the proper colorings. The minimum number of colors in a coloring of minimum weight is the cost chromatic number or strength of the graph. We derive general upper bounds for the strength, in terms of a new parameter of representations by edge intersections of hypergraphs.

The depression of a graph and k-kernels

Mark Schurch, Christine Mynhardt (2014)

Discussiones Mathematicae Graph Theory

An edge ordering of a graph G is an injection f : E(G) → R, the set of real numbers. A path in G for which the edge ordering f increases along its edge sequence is called an f-ascent ; an f-ascent is maximal if it is not contained in a longer f-ascent. The depression of G is the smallest integer k such that any edge ordering f has a maximal f-ascent of length at most k. A k-kernel of a graph G is a set of vertices U ⊆ V (G) such that for any edge ordering f of G there exists a maximal f-ascent of...

The diameter of paired-domination vertex critical graphs

Michael A. Henning, Christina M. Mynhardt (2008)

Czechoslovak Mathematical Journal

In this paper we continue the study of paired-domination in graphs introduced by Haynes and Slater (Networks 32 (1998), 199–206). A paired-dominating set of a graph G with no isolated vertex is a dominating set of vertices whose induced subgraph has a perfect matching. The paired-domination number of G , denoted by γ pr ( G ) , is the minimum cardinality of a paired-dominating set of G . The graph G is paired-domination vertex critical if for every vertex v of G that is not adjacent to a vertex of degree one,...

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