Central fringe

Central fringe --- центральная область.

Some central vertices of [math]\displaystyle{ G }[/math] are barely in [math]\displaystyle{ C(G) }[/math], in the sense that they are adjacent to the vertices that are not central. The subgraph of [math]\displaystyle{ C(G) }[/math] induced by those vertices with central distance [math]\displaystyle{ 0 }[/math] is called the central fringe of [math]\displaystyle{ G }[/math] and is denoted by [math]\displaystyle{ CF(G) }[/math].