Adjacent vertices

Adjacent vertices --- смежные вершины.

1. Two different vertices that incident with the same edge are called adjacent vertices.

2. In a digraph [math]\displaystyle{ G = (V,A) }[/math], a vertex [math]\displaystyle{ u }[/math] is adjacent to [math]\displaystyle{ v }[/math] if [math]\displaystyle{ (u,v) \in A(G) }[/math], and [math]\displaystyle{ u }[/math] is adjacent from [math]\displaystyle{ w }[/math] if [math]\displaystyle{ (w,u) \in A(G) }[/math].

3. On adjacent vertices in a hypergraph, see Partial edge.