  Using a notation of corner between edges when graph has a fixed rotation,
i.e. cyclical order of edges around vertices, we define combinatorial objects -
combinatorial maps as pairs of permutations, one for vertices and one for
faces. Further, we define multiplication of these objects, that coincides with
the multiplication of permutations. We consider closed under multiplication
classes of combinatorial maps that consist of closed classes of combinatorial
maps with fixed edges where each such class is defined by a knot. One class
among them is special, containing selfconjugate maps.
