Special parity of perfect matchings in bipartite graphs
โ Scribed by Ron Aharoni; Rachel Manber; Bronislaw Wajnryb
- Publisher
- Elsevier Science
- Year
- 1990
- Tongue
- English
- Weight
- 527 KB
- Volume
- 79
- Category
- Article
- ISSN
- 0012-365X
No coin nor oath required. For personal study only.
โฆ Synopsis
Let G be a bipartite graph in which every edge belongs to some perfect matching, and let D be a subset of its edge set. It is shown that M fl D has the same parity for every perfect matching M if and only if D is a cut, and equivalently if and only. if (G, D) is a balanced signed-graph. This gives necessary and sufficient conditions on the sign pattern of an n x n real matrix under which all nonzero terms in its permanent expansion have the same sign.
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