Vertex switch

Vertex switch --- переключатель вершин.

A vertex switch of a simple, undirected graph [math]\displaystyle{ G = (V,E) }[/math] at a vertex [math]\displaystyle{ v }[/math] is obtained by deleting the edges incident to [math]\displaystyle{ v }[/math] ad adding to [math]\displaystyle{ G }[/math] all edges that are incident to [math]\displaystyle{ v }[/math] in [math]\displaystyle{ \bar{G} }[/math]. Vertex switching was first introduced by van Lint and Seidel and is often referred to as Seidel switching.