On graphs with equal domination and 2-domination numbers
نویسندگان
چکیده
منابع مشابه
On graphs with equal domination and 2-domination numbers
Theorem 3. (Hansberg, Volkmann [4], 2007) Let G be a cactus graph. Then γ2(G) = γ(G) if and only if G is a C4-cactus. Let H be the family of graphs such that G ∈ H if and only if either G arises from a cartesian product Kp ×Kp of two complete graphs of order p for an integer p ≥ 3 by inflating every vertex but the ones on a transversal to a clique of arbitrary order, or G is a claw-free graph w...
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For a graph G a subset D of the vertex set of G is a k-dominating set if every vertex not in D has at least k neighbors in D. The k-domination number γk(G) is the minimum cardinality among the k-dominating sets of G. Note that the 1-domination number γ1(G) is the usual domination number γ(G). Fink and Jacobson showed in 1985 that the inequality γk(G) ≥ γ(G) + k − 2 is valid for every connected ...
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Let G = (V,E) be a graph. The distance between two vertices u and v in a connected graph G is the length of the shortest (u−v) path in G. A set D ⊆ V (G) is a dominating set if every vertex of G is at distance at most 1 from an element of D. The domination number of G is the minimum cardinality of a dominating set of G. A set D ⊆ V (G) is a 2-distance dominating set if every vertex of G is at d...
متن کاملClaw-Free Graphs with Equal 2-Domination and Domination Numbers
For a graph G a subsetD of the vertex set of G is a k-dominating set if every vertex not in D has at least k neighbors in D. The k-domination number γk(G) is the minimum cardinality among the k-dominating sets of G. Note that the 1-domination number γ1(G) is the usual domination number γ(G). Fink and Jacobson showed in 1985 that the inequality γk(G) ≥ γ(G) + k − 2 is valid for every connected g...
متن کاملOn graphs with equal total domination and connected domination numbers
A subset S of V is called a total dominating set if every vertex in V is adjacent to some vertex in S. The total domination number γt (G) of G is the minimum cardinality taken over all total dominating sets of G. A dominating set is called a connected dominating set if the induced subgraph 〈S〉 is connected. The connected domination number γc(G) of G is the minimum cardinality taken over all min...
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ژورنال
عنوان ژورنال: Discrete Mathematics
سال: 2008
ISSN: 0012-365X
DOI: 10.1016/j.disc.2007.04.057