Geodesically convex set of vertices

Geodesically convex set of vertices --- геодезически выпуклое множество вершин.

Given a graph [math]\displaystyle{ G = (V,E) }[/math], a subset [math]\displaystyle{ S \subseteq V }[/math] is geodesically convex if for any two vertices [math]\displaystyle{ u,v \in S }[/math] all vertices on the shortest paths between [math]\displaystyle{ u }[/math] and [math]\displaystyle{ v }[/math] are also contained in [math]\displaystyle{ S }[/math].