منابع مشابه
On kernel-perfect orientations of line graphs
We exploit the technique of Galvin (1995) to prove that an orientation D of a line-graph G (of a multigraph) is kernel-perfect if and only if every oriented odd cycle in D has a chord (or pseudochord) and every clique has a kernel. @ 1998 Elsevier Science B.V. All rights reserved
متن کاملPerfect one-factorizations in line-graphs and planar graphs
A one-factorization of a regular graph G is perfect if the union of any two one-factors is a Hamiltonian cycle. A graph G is said to be P1F if it possess a perfect one-factorization. We prove that G is a P1F cubic graph if and only if L(G) is a P1F quartic graph. Moreover, we give some necessary conditions for the existence of a P1F planar graph.
متن کاملOn characterizing game-perfect graphs by forbidden induced subgraphs
A graph G is called g-perfect if, for any induced subgraph H of G, the game chromatic number of H equals the clique number of H. A graph G is called g-col-perfect if, for any induced subgraph H of G, the game coloring number of H equals the clique number of H. In this paper we characterize the classes of g-perfect resp. g-col-perfect graphs by a set of forbidden induced subgraphs. Moreover, we ...
متن کاملCounting perfect matchings in n-extendable graphs
The structural theory of matchings is used to establish lower bounds on the number of perfect matchings in n-extendable graphs. It is shown that any such graph on p vertices and q edges contains at least (n + 1)!/4[q − p − (n − 1)(2 − 3) + 4] different perfect matchings, where is the maximum degree of a vertex in G. © 2007 Elsevier B.V. All rights reserved. MSC: 05C70; 05C40; 05C75
متن کاملCharacterizing minimally n-extendable bipartite graphs
In this paper, it is proved that let G be a bipartite graph with bipartition (X, Y ) and with a perfect matching M , let G be an n-extendable graph, then G is minimally n-extendable if and only if, for any two vertices x ∈ X and y ∈ Y such that xy ∈ E(G), there are exactly n internally disjoint (x, y) M-alternating paths P1, P2, . . . , Pn such that Pi (1 i n) starts and ends with edges in E(G)...
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ژورنال
عنوان ژورنال: International Transactions in Operational Research
سال: 2016
ISSN: 0969-6016
DOI: 10.1111/itor.12275