reserve G, G1, G2 for _Graph, H for Subgraph of G;

theorem Th61:
  for H being spanning Subgraph of G
  holds H | _GraphSelectors in G.allSpanningSG()
proof
  let H be spanning Subgraph of G;
  H | _GraphSelectors == H by GLIB_000:128;
  then H | _GraphSelectors is spanning Subgraph of G by GLIB_000:171;
  hence thesis by Th60;
end;
