Semisymmetric graph

Semisymmetric graph --- полусимметричный граф.

Let [math]\displaystyle{ G }[/math] be a subgroup of the full automorphism group of a graph [math]\displaystyle{ X }[/math]. We call [math]\displaystyle{ X }[/math] [math]\displaystyle{ G }[/math]semisymmetric graph, if it is regular and [math]\displaystyle{ G }[/math] acts transitively on its edge set but not on its vertex set.