Goal:
    G : t  s : VSet.t  s' : VSet.t  x : V.t  y : V.t
  ============================
   (VSet.Subset s s' -> (lsp0 s x y <= lsp0 s' x y)%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 := lsp0 s x y
of type
constr of type tacvalue