Sharp Upper Bounds on the Clar Number of Fullerene Graphs

Yang Gao; Heping Zhang

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Displaying similar documents to “Sharp Upper Bounds on the Clar Number of Fullerene Graphs”

Relations between the domination parameters and the chromatic index of a graph

Włodzimierz Ulatowski (2009)

Discussiones Mathematicae Graph Theory

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In this paper we show upper bounds for the sum and the product of the lower domination parameters and the chromatic index of a graph. We also present some families of graphs for which these upper bounds are achieved. Next, we give a lower bound for the sum of the upper domination parameters and the chromatic index. This lower bound is a function of the number of vertices of a graph and a new graph parameter which is defined here. In this case we also characterize graphs for which a respective...

Bound graph polysemy.

Tanenbaum, Paul J. (2000)

The Electronic Journal of Combinatorics [electronic only]

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Lower bounds for the domination number

Ermelinda Delaviña, Ryan Pepper, Bill Waller (2010)

Discussiones Mathematicae Graph Theory

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In this note, we prove several lower bounds on the domination number of simple connected graphs. Among these are the following: the domination number is at least two-thirds of the radius of the graph, three times the domination number is at least two more than the number of cut-vertices in the graph, and the domination number of a tree is at least as large as the minimum order of a maximal matching.

Bounds on the Signed 2-Independence Number in Graphs

Lutz Volkmann (2013)

Discussiones Mathematicae Graph Theory

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Let G be a finite and simple graph with vertex set V (G), and let f V (G) → {−1, 1} be a two-valued function. If ∑x∈N|v| f(x) ≤ 1 for each v ∈ V (G), where N[v] is the closed neighborhood of v, then f is a signed 2-independence function on G. The weight of a signed 2-independence function f is w(f) =∑v∈V (G) f(v). The maximum of weights w(f), taken over all signed 2-independence functions f on G, is the signed 2-independence number α2s(G) of G. In this work, we mainly present upper bounds...

On dominating the Cartesian product of a graph and K₂

Bert L. Hartnell, Douglas F. Rall (2004)

Discussiones Mathematicae Graph Theory

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In this paper we consider the Cartesian product of an arbitrary graph and a complete graph of order two. Although an upper and lower bound for the domination number of this product follow easily from known results, we are interested in the graphs that actually attain these bounds. In each case, we provide an infinite class of graphs to show that the bound is sharp. The graphs that achieve the lower bound are of particular interest given the special nature of their dominating sets and...

Upper and lower bounds for $F_{v} (4, 4; 5)$ .

Xu, Xiaodong, Luo, Haipeng, Shao, Zehui (2010)

The Electronic Journal of Combinatorics [electronic only]

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The bondage number of graphs: good and bad vertices

Vladimir Samodivkin (2008)

Discussiones Mathematicae Graph Theory

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The domination number γ(G) of a graph G is the minimum number of vertices in a set D such that every vertex of the graph is either in D or is adjacent to a member of D. Any dominating set D of a graph G with |D| = γ(G) is called a γ-set of G. A vertex x of a graph G is called: (i) γ-good if x belongs to some γ-set and (ii) γ-bad if x belongs to no γ-set. The bondage number b(G) of a nonempty graph G is the cardinality of a smallest set of edges whose removal from G results in a graph...

Offensive alliances in graphs

Odile Favaron, Gerd Fricke, Wayne Goddard, Sandra M. Hedetniemi, Stephen T. Hedetniemi, Petter Kristiansen, Renu C. Laskar, R. Duane Skaggs (2004)

Discussiones Mathematicae Graph Theory

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A set S is an offensive alliance if for every vertex v in its boundary N(S)- S it holds that the majority of vertices in v's closed neighbourhood are in S. The offensive alliance number is the minimum cardinality of an offensive alliance. In this paper we explore the bounds on the offensive alliance and the strong offensive alliance numbers (where a strict majority is required). In particular, we show that the offensive alliance number is at most 2/3 the order and the strong offensive...

The leafage of a chordal graph

In-Jen Lin, Terry A. McKee, Douglas B. West (1998)

Discussiones Mathematicae Graph Theory

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The leafage l(G) of a chordal graph G is the minimum number of leaves of a tree in which G has an intersection representation by subtrees. We obtain upper and lower bounds on l(G) and compute it on special classes. The maximum of l(G) on n-vertex graphs is n - lg n - 1/2 lg lg n + O(1). The proper leafage l*(G) is the minimum number of leaves when no subtree may contain another; we obtain upper and lower bounds on l*(G). Leafage equals proper leafage on claw-free chordal graphs. We use...

Signed k-independence in graphs

Lutz Volkmann (2014)

Open Mathematics

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Let k ≥ 2 be an integer. A function f: V(G) → −1, 1 defined on the vertex set V(G) of a graph G is a signed k-independence function if the sum of its function values over any closed neighborhood is at most k − 1. That is, Σx∈N[v] f(x) ≤ k − 1 for every v ∈ V(G), where N[v] consists of v and every vertex adjacent to v. The weight of a signed k-independence function f is w(f) = Σv∈V(G) f(v). The maximum weight w(f), taken over all signed k-independence functions f on G, is the signed k-independence...

Improved upper bounds for the Laplacian spectral radius of a graph.

Wang, Tianfei, Yang, Jin, Li, Bin (2011)

The Electronic Journal of Combinatorics [electronic only]

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Remarks on the bounds of graph energy in terms of vertex cover number or matching number

Xiaodan Chen, Xiaoqian Liu (2021)

Czechoslovak Mathematical Journal

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We give a novel upper bound on graph energy in terms of the vertex cover number, and present a complete characterization of the graphs whose energy equals twice their matching number.

Contraction and treewidth lower bounds.

Bodlaender, Hans L., Wolle, Thomas, Koster, Arie M.C.A. (2006)

Journal of Graph Algorithms and Applications

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