منابع مشابه
The subgraph homeomorphism problem on reducible flow graphs
We investigate the subgraph homeomorphism problem in which one would like to determine whether a fixed pattern graph is hcmeomorphic to a subgraph of an input graph. We show that for every fixed pattern graph, there is a polynomial-time algorithm to solve the problem if the input graphs are restricted to reducible flow graphs.
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Let IL be the set of all hereditary and additive properties of graphs. For P1,P2 ∈ IL, the reducible property R = P1 ◦ P2 is defined as follows: G ∈ R if and only if there is a partition V (G) = V1 ∪ V2 of the vertex set of G such that 〈V1〉G ∈ P1 and 〈V2〉G ∈ P2. The aim of this paper is to investigate the structure of the reducible properties of graphs with emphasis on the uniqueness of the dec...
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For a given graph G and a sequence P1,P2, . . . ,Pn of additive hereditary classes of graphs we define an acyclic (P1,P2, . . . ,Pn)colouring of G as a partition (V1, V2, . . . , Vn) of the set V (G) of vertices which satisfies the following two conditions: 1. G[Vi] ∈ Pi for i = 1, . . . , n, 2. for every pair i, j of distinct colours the subgraph induced in G by the set of edges uv such that u...
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A bull is a graph with five vertices r, y, x, z, s and five edges ry, yx, yz, xz, zs. A graph G is bull-reducible if no vertex of G lies in two bulls. We prove that every bull-reducible Berge graph G that contains no antihole is weakly chordal, or has a homogeneous set, or is transitively orientable. This yields a fast polynomial time algorithm to color exactly the vertices of such a graph.
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The P,-reducible graphs are a natural generalization of the well-known class of cographs, with applications to scheduling, computational semantics, and clustering. More precisely, the Pa-reducible graphs are exactly the graphs none of whose vertices belong to more than one chordless path with three edges. A remarkable property of P,-reducible graphs is their unique tree representation up to iso...
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ژورنال
عنوان ژورنال: Journal of Computer and System Sciences
سال: 1976
ISSN: 0022-0000
DOI: 10.1016/s0022-0000(76)80042-6