
theorem Th40:
  for G being Cycle-like _Graph holds G.order() = G.size()
proof
  let G be Cycle-like _Graph;
  2*G.size() = 2*`G.size() by FIELD_5:2
    .= 2*`G.order() by GLIB_016:58
    .= 2*G.order() by FIELD_5:2;
  hence thesis;
end;
