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

theorem Th104:
  for H being spanning acyclic Subgraph of G
  holds H | _GraphSelectors in G.allSpanningForests()
proof
  let H be spanning acyclic Subgraph of G;
  H | _GraphSelectors == H by GLIB_000:128;
  then H | _GraphSelectors is spanning acyclic Subgraph of G
    by GLIB_000:171, GLIB_002:44;
  hence thesis by Th102;
end;
