Goal:
  
  G1 : t
  G2 : t
  H : invariants G1
  H0 : invariants G2
  H1 : acyclic_no_loop G2
  hsub : subgraph G1 G2
  ext : is_true (is_full_extension G1 G2)
  acG1 : acyclic_no_loop G1
  ============================
   (forall x y : VSet.elt,
    VSet.In x (V G1) -> VSet.In y (V G1) -> (lsp G2 x y <= lsp G1 x y)%nbar)


DEBUG:Going to execute:
<coq-core.plugins.ssreflect::ssrapply@0> $1
DEBUG LTAC Evaluated term: (subgraph_acyclic G1 G2 hsub H1)