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

theorem
  for G3 being removeLoops of G1, G4 being removeLoops of G2
  holds G4 is G3-isomorphic implies
    G1.allSpanningForests(),G2.allSpanningForests() are_isomorphic
proof
  let G3 be removeLoops of G1, G4 be removeLoops of G2;
  G1.allSpanningForests() = G3.allSpanningForests() &
    G2.allSpanningForests() = G4.allSpanningForests() by Th110;
  hence thesis by Th116;
end;
