Coverings of Bipartite Graphs

@article{Dulmage1958CoveringsOB,
  title={Coverings of Bipartite Graphs},
  author={A. L. Dulmage and N. S. Mendelsohn},
  journal={Canadian Journal of Mathematics},
  year={1958},
  volume={10},
  pages={517 - 534}
}
For the purpose of analysing bipartite graphs (hereinafter called simply graphs) the concept of an exterior covering is introduced. In terms of this concept it is possible in a natural way to decompose any graph into two parts, an inadmissible part and a core. It is also possible to decompose the core into irreducible parts and thus obtain a canonical reduction of the graph. The concept of irreducibility is very easily and naturally expressed in terms of exterior coverings. The role of the… 

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