{ "id": "1708.00582", "version": "v1", "published": "2017-08-02T02:42:43.000Z", "updated": "2017-08-02T02:42:43.000Z", "title": "Excluded $t$-factors in Bipartite Graphs: Unified Framework for Nonbipartite Matchings, Restricted 2-matchings, and Matroids", "authors": [ "Kenjiro Takazawa" ], "comment": "23 pages, 7 figures, A preliminary version of this paper appears in Proceedings of the 19th IPCO (2017)", "categories": [ "math.CO", "cs.DM", "cs.DS" ], "abstract": "We propose a framework for optimal $t$-matchings excluding the prescribed $t$-factors in bipartite graphs. The proposed framework is a generalization of the nonbipartite matching problem and includes several problems, such as the triangle-free $2$-matching, square-free $2$-matching, even factor, and arborescence problems. In this paper, we demonstrate a unified understanding of these problems by commonly extending previous important results. We solve our problem under a reasonable assumption, which is sufficiently broad to include the specific problems listed above. We first present a min-max theorem and a combinatorial algorithm for the unweighted version. We then provide a linear programming formulation with dual integrality and a primal-dual algorithm for the weighted version. A key ingredient of the proposed algorithm is a technique to shrink forbidden structures, which corresponds to the techniques of shrinking odd cycles, triangles, squares, and directed cycles in Edmonds' blossom algorithm, a triangle-free $2$-matching algorithm, a square-free $2$-matching algorithm, and an arborescence algorithm, respectively.", "revisions": [ { "version": "v1", "updated": "2017-08-02T02:42:43.000Z" } ], "analyses": { "keywords": [ "bipartite graphs", "unified framework", "matching algorithm", "shrink forbidden structures", "triangle-free" ], "note": { "typesetting": "TeX", "pages": 23, "language": "en", "license": "arXiv", "status": "editable" } } }