Goal:
  
  G : t
  HI : invariants
  HG : acyclic_no_loop
  x : VSet.elt
  inx : VSet.In x (V G)
  m : Z
  Hm : lsp (s G) x = Some m
  Hpos : (0 <=? m) = true
  ============================
   (m = m)


DEBUG:Going to execute:
(solve [ do_atom | use_hyps; do_ccl ]) ||
             fail "Cannot solve this goal"