
theorem Th68:
  for G1 being _Graph, G2, G3 being LGraphComplement of G1
  holds G3 is G2-isomorphic
proof
  let G1 be _Graph, G2, G3 be LGraphComplement of G1;
  G1 is G1-isomorphic by GLIB_010:53;
  hence thesis by Th67;
end;
