Transactions of the American Mathematical Society · 1980 · 41 citations · 7 references
Natural SciencesComputer ScienceMathematicsCombinatoricsComputational GeometryData StructuresCombinatorial EnumerationEnumerative CombinatoricsGeometric GraphsGraph AlgorithmsGraph TheoryTopological CombinatoricsCombinatorial RepresentationsEnumerative Graph TheoryGraph EmbeddingsPermutation GraphsTopological Graph Theory
Permutation-partition pairs are a purely combinatorial generalization of graph embeddings. Some parameters are defined here for these pairs and several theorems are proved. These results are strong enough to prove virtually all the known theoretical informaton about the genus parameter as well as a new theorem regarding the genus of the amalgamation of two graphs over three points.
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Percy J. Heawood · Proceedings of the London Mathematical Society · 1949 · 224 citations
Hypermaps versus bipartite maps
Timothy R. Walsh · Journal of Combinatorial Theory Series B · 1975 · 189 citations
Ramified coverings of Riemann surfaces
Dale Husemöller · Duke Mathematical Journal · 1962 · 64 citations