Goal:
    G : t  HI : invariants G  HG : acyclic_no_loop G  n : Z  x : V.t  y : V.t
  ============================
   (n <= 0 /\ (x = y \/ (Some n <= lsp G x (s G))%nbar) <->
    (n <=? 0) && (V.eq_dec x y || le_dec (Some n) (lsp G x (s G))))


DEBUG:Going to execute:
fun => <coq-core.plugins.ltac::symmetry@0>