Deficiency is a concept in graph theory that is used to refine various theorems related to perfect matching in graphs, such as Hall's marriage theorem. This was first studied by Øystein Ore.[1][2]: 17 A related property is surplus.
- ^ Ore, Oystein (1955-12-01). "Graphs and matching theorems". Duke Mathematical Journal. 22 (4): 625–639. doi:10.1215/S0012-7094-55-02268-7. ISSN 0012-7094.
- ^ Lovász, László; Plummer, M. D. (1986), Matching Theory, Annals of Discrete Mathematics, vol. 29, North-Holland, ISBN 0-444-87916-1, MR 0859549