Displaying similar documents to “ Characterization of Cubic Graphs G with ir t (G) = Ir t (G) = 2 ”

Secure sets and their expansion in cubic graphs

Katarzyna Jesse-Józefczyk, Elżbieta Sidorowicz (2014)

Open Mathematics

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Consider a graph whose vertices play the role of members of the opposing groups. The edge between two vertices means that these vertices may defend or attack each other. At one time, any attacker may attack only one vertex. Similarly, any defender fights for itself or helps exactly one of its neighbours. If we have a set of defenders that can repel any attack, then we say that the set is secure. Moreover, it is strong if it is also prepared for a raid of one additional foe who can strike...

Graphs with disjoint dominating and paired-dominating sets

Justin Southey, Michael Henning (2010)

Open Mathematics

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A dominating set of a graph is a set of vertices such that every vertex not in the set is adjacent to a vertex in the set, while a paired-dominating set of a graph is a dominating set such that the subgraph induced by the dominating set contains a perfect matching. In this paper, we show that no minimum degree is sufficient to guarantee the existence of a disjoint dominating set and a paired-dominating set. However, we prove that the vertex set of every cubic graph can be partitioned...

On total vertex irregularity strength of graphs

K. Muthu Guru Packiam, Kumarappan Kathiresan (2012)

Discussiones Mathematicae Graph Theory

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Martin Bača et al. [2] introduced the problem of determining the total vertex irregularity strengths of graphs. In this paper we discuss how the addition of new edge affect the total vertex irregularity strength.

The ramsey number for theta graph versus a clique of order three and four

M.S.A. Bataineh, M.M.M. Jaradat, M.S. Bateeha (2014)

Discussiones Mathematicae Graph Theory

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For any two graphs F1 and F2, the graph Ramsey number r(F1, F2) is the smallest positive integer N with the property that every graph on at least N vertices contains F1 or its complement contains F2 as a subgraph. In this paper, we consider the Ramsey numbers for theta-complete graphs. We determine r(θn,Km) for m = 2, 3, 4 and n > m. More specifically, we establish that r(θn,Km) = (n − 1)(m − 1) + 1 for m = 3, 4 and n > m

Gallai and anti-Gallai graphs of a graph

S. Aparna Lakshmanan, S. B. Rao, A. Vijayakumar (2007)

Mathematica Bohemica

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The paper deals with graph operators—the Gallai graphs and the anti-Gallai graphs. We prove the existence of a finite family of forbidden subgraphs for the Gallai graphs and the anti-Gallai graphs to be H -free for any finite graph H . The case of complement reducible graphs—cographs is discussed in detail. Some relations between the chromatic number, the radius and the diameter of a graph and its Gallai and anti-Gallai graphs are also obtained.