Results 111 to 120 of about 9,740 (155)
The spectral Turán problem about graphs of given size with forbidden subgraphs
AKCE International Journal of Graphs and CombinatoricsLet G be a graph of size m and [Formula: see text] be the spectral radius of its adjacency matrix. A graph is said to be H-free if it does not contain a subgraph isomorphic to H. Let [Formula: see text] be the graph obtained by adding a pendent vertex to
Amir Rehman, S. Pirzada
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Graphs with forbidden subgraphs
Journal of Combinatorial Theory, Series B, 1971 AbstractMany graphs which are encountered in the study of graph theory are characterized by a type of configuration or subgraph they possess. However, there are occasions when such graphs are more easily defined or described by the kind of subgraphs they are not permitted to contain.
Chartrand, Gary +2 more
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Line game-perfect graphs [PDF]
Discrete Mathematics & Theoretical Computer ScienceThe $[X,Y]$-edge colouring game is played with a set of $k$ colours on a graph $G$ with initially uncoloured edges by two players, Alice (A) and Bob (B). The players move alternately. Player $X\in\{A,B\}$ has the first move. $Y\in\{A,B,-\}$.
Stephan Dominique Andres, Wai Lam Fong
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On the Caccetta-Haggkvist conjecture with forbidden subgraphs
J. Graph Theory, 2011 The Caccetta-Haggkvist conjecture made in 1978 asserts that every orgraph on n vertices without oriented cycles of length <= l must contain a vertex of outdegree at most (n-1)/l. It has a rather elaborate set of (conjectured) extremal configurations. In this paper we consider the case l=3 that received quite a significant attention in the literature.
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Path Eccentricity and Forbidden Induced Subgraphs
CoRRAbstract.
Cichacz, Sylwia +4 more
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Discussiones Mathematicae Graph Theory, 2017 We characterize the class L32$L_3^2 $ of intersection graphs of hypergraphs with rank at most 3 and multiplicity at most 2 by means of a finite list of forbidden induced subgraphs in the class of threshold graphs.
Metelsky Yury +2 more
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On the validity of Lovász’s inequality for induced star-perfect graphs
Journal of Inequalities and ApplicationsLet F $\mathcal{F}$ be a family of graphs. For a graph G, define θ F ( G ) $\theta _{F}(G)$ as the minimum number of induced subgraphs of G, each isomorphic to a member of F $\mathcal{F}$ , needed to cover V ( G ) $V(G)$ , and α F ( G ) $\alpha _{F}(G ...
James Alex, Louis Caccetta
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DP-4-Colorability on Planar Graphs Excluding 7-Cycles Adjacent to 4- or 5-Cycles
MathematicsIn order to resolve Borodin’s Conjecture, DP-coloring was introduced in 2017 to extend the concept of list coloring. In previous works, it is proved that every planar graph without 7-cycles and butterflies is DP-4-colorable.
Fan Yang, Xiangwen Li, Ziwen Huang
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Flips in colorful triangulations
Journal of Computational GeometryThe associahedron is the graph $\mathcal{G}_N$ that has as nodes all triangulations of a convex $N$-gon, and an edge between any two triangulations that differ in a flip operation.
Rohan Acharya +2 more
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Журнал Белорусского государственного университета: Математика, информатика, 2018 Let Lm(k) denote the class of edge intersection graphs of k-chromatic hypergraphs with multiplicity at most m. It is known that the problem of recognizing graphs from L1(k) is polynomially solvable if k = 2 and is NP-complete if k = 3.
Tatiana V. Lubasheva, Yury M. Metelsky
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