Matching structure and the matching lattice
Matching structure and the matching lattice
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DOI:
10.1016/0095-8956(87)90021-9
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发表时间:
1987-10
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影响因子:
--
通讯作者:
L. Lovász
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文献类型:
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作者:
L. Lovász
The matching polyhedron, i.e., theconvex hullof (incidence vectors of) perfect matchings of a graph was characterized by Edmonds; this result is the key to a large part of polyhedral combinatorics and is used in many combinatorial algorithms. Thelinear hullof perfect matchings was characterized by Naddef, and by Edmonds, Lovász, and Pulleyblank. In this paper we describe thelatticegenerated by these vectors, i.e., the set of all integer linear combinations of perfect matchings. It turns out that the Petersen graph is, in a sense, the only difficult example. Our results also imply a characterization of the linear hull of perfect matchings over fields of characteristic different from 0. The main method is a decomposition theory developed by Kotzig, Lovász, and Plummer, which breaks down every graph into a number of graphs calledbrickswith very good matching properties. The number of Petersen graphs among these bricks will turn out to be an essential parameter of the matching lattice. Some refinements of the decomposition theory are also given. Among others, we show that the list of bricks obtained during the decomposition procedure is independent of the special choices made during the procedure.