Topic summary
Rotation system
Extracted from the Wikipedia article Combinatorial map.
Rotation systems
In combinatorialmathematics, rotation systems (also called combinatorial embeddings or combinatorial maps) encode embeddings of graphs onto orientablesurfaces by describing the circular ordering of a graph's edges around each vertex. A more formal definition of a rotation system involves pairs of permutations; such a pair is sufficient to determine a multigraph, a surface, and a 2-cell embedding of the multigraph onto the surface.