Central distance

Central distance --- центральное расстояние.

The central distance [math]\displaystyle{ c(v) }[/math] of [math]\displaystyle{ v }[/math] is the largest nonnegative integer [math]\displaystyle{ n }[/math] such that whenever [math]\displaystyle{ d(v,x) \leq n }[/math] the vertex [math]\displaystyle{ x }[/math] is in the center of [math]\displaystyle{ G }[/math].