Results 91 to 100 of about 211 (163)
Nilpotent graphs with crosscap at most two
AKCE International Journal of Graphs and Combinatorics, 2018 Let R be a commutative ring with identity. The nilpotent graph of R, denoted by Γ N ( R ) , is a graph with vertex set Z N ( R ) ∗ , and two vertices x and y are adjacent if and only if x y is nilpotent, where Z N ( R ) = { x ∈ R : x y is nilpotent, for ...
A. Mallika, R. Kala
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Non-Preemptive Tree Packing. [PDF]
Algorithmica, 2023 Lendl S, Woeginger G, Wulf L.
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A graph and its complement with specified properties I: connectivity
International Journal of Mathematics and Mathematical Sciences, 1979 We investigate the conditions under which both a graph G and its complement G¯ possess a specified property. In particular, we characterize all graphs G for which G and G¯ both (a) have connectivity one, (b) have line-connectivity one, (c) are 2 ...
Jin Akiyama, Frank Harary
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On the Upward Planarity of Mixed Plane Graphs
Journal of Graph Algorithms and Applications, 2014 A mixed plane graph is a plane graph whose edge set is partitioned into a set of directed edges and a set of undirected edges. An orientation of a mixed plane graph G is an assignment of directions to the undirected edges of G resulting in a directed ...
Fabrizio Frati +4 more
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Chromatic Sums for Colorings Avoiding Monochromatic Subgraphs
Discussiones Mathematicae Graph Theory, 2015 Given graphs G and H, a vertex coloring c : V (G) →ℕ is an H-free coloring of G if no color class contains a subgraph isomorphic to H. The H-free chromatic number of G, χ (H,G), is the minimum number of colors in an H-free coloring of G.
Kubicka Ewa +2 more
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Mitochondrial networks through the lens of mathematics. [PDF]
Phys Biol, 2023 Lewis GR, Marshall WF.
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On reconstructing maximal outerplanar graphs
Discrete Mathematics, 1974 Manvel has proved that a maximal outerplanar graph can be reconstructed from the collection of isomorphism types of subgraphs obtained by deleting vertices of the given graph. This paper sharpens Manvel's result by showing that if the graph is not a triangulation of a hexagon, then reconstruction can be accomplished using only those isomorphism types ...
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The complexity of frugal colouring. [PDF]
Arab J Math, 2021 Bard S, MacGillivray G, Redlin S.
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On the k-Structure Ratio in Planar and Outerplanar Graphs
Discrete Mathematics & Theoretical Computer Science, 2008 A planar k-restricted structure is a simple graph whose blocks are planar and each has at most k vertices. Planar k-restricted structures are used by approximation algorithms for Maximum Weight Planar Subgraph, which motivates this work. The planar k-
Gruia Calinescu, Cristina G. Fernandes
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Horizontal visibility graph of a random restricted growth sequence. [PDF]
Adv Appl Math, 2021 Mansour T, Rastegar R, Roitershtein A.
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