Goal:
  
  G : t
  HI : invariants
  HG : acyclic_no_loop
  x : V.t
  y : V.t
  z : V.t
  n : Z
  Hn : lsp x y = Some n
  ============================
   (Some n + lsp y z <= lsp x z)%nbar


DEBUG:Going to execute:
generalize eq_refl; pattern x at - 1
Level 1: evaluation returns
generalize eq_refl; pattern x at - 1; case x
where
x := lsp y z
of type
constr of type tacvalue