Results 11 to 20 of about 176 (148)
Outerplanar and Planar Oriented Cliques [PDF]
Journal of Graph Theory, 2015 AbstractThe clique number of an undirected graph G is the maximum order of a complete subgraph of G and is a well‐known lower bound for the chromatic number of G. Every proper k‐coloring of G may be viewed as a homomorphism (an edge‐preserving vertex mapping) of G to the complete graph of order k.
Ayan Nandy +2 more
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Large Induced Acyclic and Outerplanar Subgraphs of 2-Outerplanar Graph [PDF]
Graphs and Combinatorics, 2017 Albertson and Berman conjectured that every planar graph has an induced forest on half of its vertices. The best known lower bound, due to Borodin, is that every planar graph has an induced forest on two fifths of its vertices. In a related result, Chartran and Kronk, proved that the vertices of every planar graph can be partitioned into three sets ...
Glencora Borradaile +2 more
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Splitting Plane Graphs to Outerplanarity
Journal of Graph Algorithms and Applications, 2023 Vertex splitting replaces a vertex by two copies and partitions its incident edges amongst the copies. This problem has been studied as a graph editing operation to achieve desired properties with as few splits as possible, most often planarity, for which the problem is NP-hard.Here we study how to minimize the number of splits to turn a plane graph ...
Martin Gronemann +2 more
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Pathwidth of outerplanar graphs [PDF]
Journal of Graph Theory, 2006 AbstractWe are interested in the relation between the pathwidth of a biconnected outerplanar graph and the pathwidth of its (geometric) dual. Bodlaender and Fomin [3], after having proved that the pathwidth of every biconnected outerplanar graph is always at most twice the pathwidth of its (geometric) dual plus two, conjectured that there exists a ...
Coudert, David +2 more
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A Characterization of Maximal Outerplanar-Open Distance Pattern Uniform Graphs
مجلة بغداد للعلوم, 2023 Let A ⊆ V(H) of any graph H, every node w of H be labeled using a set of numbers; , where d(w,v) denotes the distance between node w and the node v in H, known as its open A-distance pattern. A graph H is known as the open distance-pattern uniform (odpu)
BIBIN K JOSE
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Nilpotent graphs with crosscap at most two
AKCE International Journal of Graphs and Combinatorics, 2018 Let be a commutative ring with identity. The nilpotent graph of , denoted by , is a graph with vertex set , and two vertices and are adjacent if and only if is nilpotent, where .
A. Mallika, R. Kala
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Approximation of pathwidth of outerplanar graphs [PDF]
Journal of Algorithms, 2001 Summary: There exists a polynomial time algorithm to compute the pathwidth of outerplanar graphs, but the large exponent makes this algorithm impractical. In this paper, we give an algorithm that, given a biconnected outerplanar graph \(G\), finds a path decomposition of \(G\) of pathwidth at most twice the pathwidth of \(G\) plus one.
Hans L. Bodlaender, Fedor V. Fomin
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The Singularity of Oriented Outerplanar Graphs with a Given Number of Inner Edges
Journal of Mathematics, 2022 A digraph is called oriented if there is at most one arc between two distinct vertices. An oriented graph is called nonsingular (singular) if its adjacency matrix AD is nonsingular (singular).
Borui He, Xianya Geng, Long Wang
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The Electronic Journal of Combinatorics, 2017 A map is outerplanar if all its vertices lie in the outer face. We enumerate various classes of rooted outerplanar maps with respect to the number of edges and vertices. The proofs involve several bijections with lattice paths. As a consequence of our results, we obtain an efficient scheme for encoding simple outerplanar maps.
Ivan Geffner, Marc Noy
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Double domination in maximal outerplanar graphs
Open Mathematics, 2022 In graph GG, a vertex dominates itself and its neighbors. A subset S⊆V(G)S\subseteq V\left(G) is said to be a double-dominating set of GG if SS dominates every vertex of GG at least twice.
Zhuang Wei, Zheng Qiuju
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