
theorem Th8:
  for G1 being _Graph, G2 being reverseEdgeDirections of G1
  holds G1 is Dcomplete iff G2 is Dcomplete
proof
  let G1 be _Graph, G2 be reverseEdgeDirections of G1;
  thus G1 is Dcomplete implies G2 is Dcomplete by Lm1;
  G1 is reverseEdgeDirections of G2, the_Edges_of G1 by GLIB_007:3;
  then G1 is reverseEdgeDirections of G2 by GLIB_007:4;
  hence thesis by Lm1;
end;
