reserve G for _Graph;

theorem Th62:
  for G1, G2 being _Graph
  holds G2 is Subgraph of G1 & G2 is Supergraph of G1 iff G1 == G2
proof
  let G1, G2 be _Graph;
  G1 == G2 iff G2 is Subgraph of G1 & G1 is Subgraph of G2 by GLIB_000:87;
  hence thesis by Th61;
end;
