Degree pair of a vertex

Degree pair of a vertex --- степенная пара вершины. Let [math]\displaystyle{ G }[/math] be a digraph and [math]\displaystyle{ v }[/math] be a vertex of [math]\displaystyle{ G }[/math].

The ordered pair [math]\displaystyle{ [outdegree(v), indegree(v)] }[/math] is called the degree pair of the vertex [math]\displaystyle{ v }[/math].