منابع مشابه
Bipartite covering graphs
In this paper we study when a bipartite graph is a covering of a non-bipartite graph. We give a characterization of all coverings in terms of factoring the covering map through the canonical double covering. We also consider regular bipartite coverings described in terms of voltage assignments. We give an algebraic characterization of such coverings involving the subgroup generated by voltages ...
متن کاملOn covering graphs by complete bipartite subgraphs
We prove that, if a graph with e edges contains m vertex-disjoint edges, then m/e complete bipartite subgraphs are necessary to cover all its edges. Similar lower bounds are also proved for fractional covers. For sparse graphs, this improves the well-known fooling set lower bound in communication complexity. We also formulate several open problems about covering problems for graphs whose soluti...
متن کاملCovering Graphs with Few Complete Bipartite Subgraphs
We consider computational problems on covering graphs with bicliques (complete bipartite subgraphs). Given a graph and an integer k, the biclique cover problem asks whether the edge-set of the graph can be covered with at most k bicliques; the biclique partition problem is defined similarly with the additional condition that the bicliques are required to be mutually edge-disjoint. The biclique ...
متن کاملComparing Unlabeled Pedigree Graphs via Covering with Bipartite and Path
Family trees, also called pedigrees, have important information about an individual's past and future life. It can be used as a diagnostic tool and help guide decisions about genetic testing for the patient and at-risk family members. There are 2% to 10% of parent-child relationships missing, and this can cause large differences in the pedigree graphs created. Hence, the evaluation of pedigrees...
متن کاملCovering the Edges of Bipartite Graphs Using K 2, 2 Graphs
An optimization problem arising in the design of optical networks is shown here to be abstracted by the following model of covering the edges of a bipartite graph with a minimum number of 4-cycles, or K2,2: Given a bipartite graph G = (L,R,E) over the node set L ∪ R with E ⊆ {[u, v] : u ∈ L, v ∈ R}, and the implicit collection of all fournode cycles in the complete bipartite graph over L∪R. The...
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ژورنال
عنوان ژورنال: Discrete Mathematics
سال: 2000
ISSN: 0012-365X
DOI: 10.1016/s0012-365x(99)00196-x