Removal of a set of vertices

Removal of a set of vertices --- удаление множества вершин.

For a given graph (digraph or hypergraph) [math]\displaystyle{ G }[/math], removal of vertices in [math]\displaystyle{ X }[/math] together with all edges incident to them. The resulting [hyper-, di-]graph is denoted by [math]\displaystyle{ G \setminus X }[/math] or [math]\displaystyle{ G - X }[/math]. If [math]\displaystyle{ X = \{x\} }[/math], it is simply [math]\displaystyle{ G - x }[/math].