Goal:
  
  G : t
  fuel : nat
  s : VSet.t
  x : V.t
  z : V.t
  IHfuel : forall (s : VSet.t) (x z : V.t),
           lsp00_fast fuel s x z = lsp00 fuel s x z
  acc : Nbar.t
  src : V.t
  w : Z
  tgt : V.t
  ============================
   ((Some w + lsp00 fuel (VSet.remove x s) tgt z)%nbar =
    (Some w + lsp00 fuel (VSet.remove x s) tgt z)%nbar)


DEBUG:Going to execute:
solve
[ trivial
with eq_true
| reflexivity
| symmetry; trivial
| contradiction
| congruence ]