منابع مشابه
A characterization of P4-comparability graphs
A graph is a P4-comparability graph if it admits an acyclic orientation of its edges which is transitive on every chordless path on four vertices. We give a characterization of P4-comparability graphs in terms of an auxiliary graph being bipartite. © 2006 Elsevier B.V. All rights reserved.
متن کاملOn the Recognition of P4-Comparability Graphs
We consider the problem of recognizing whether a simple undirected graph is a P4-comparability graph. This problem has been considered by Hoàng and Reed who described an O(n)-time algorithm for its solution, where n is the number of vertices of the given graph. Faster algorithms have recently been presented by Raschle and Simon and by Nikolopoulos and Palios; the time complexity of both algorit...
متن کاملParallel algorithms for P4-comparability graphs
We consider two problems pertaining to P4-comparability graphs, namely, the problem of recognizing whether a simple undirected graph is a P4-comparability graph and the problem of producing an acyclic P4-transitive orientation of such a graph. Sequential algorithms for these problems have been presented by Hoàng and Reed and very recently by Raschle and Simon, and by Nikolopoulos and Palios. In...
متن کاملRecognition and Orientation Algorithms for P4-Comparability Graphs
We consider two problems pertaining to P4-comparability graphs, namely, the problem of recognizing whether a simple undirected graph is a P4-comparability graph and the problem of producing an acyclic P4-transitive orientation of a P4-comparability graph. These problems have been considered by Hoàng and Reed who described O(n) and O(n)-time algorithms for their solution respectively, where n is...
متن کاملEven and Odd Pairs in Comparability and in P4-comparability Graphs
We characterize even and odd pairs in comparability and in P 4-comparability graphs. The characterizations lead to simple algorithms for deciding whether a given pair of vertices forms an even or odd pair in these classes of graphs. The complexities of the proposed algorithms are O(n + m) for comparability graphs and O(n 2 m) for P 4-comparability graphs. The former represents an improvement ov...
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ژورنال
عنوان ژورنال: Discrete Mathematics
سال: 1989
ISSN: 0012-365X
DOI: 10.1016/0012-365x(89)90209-4