Goal:
  
  G : t
  HI : invariants G
  HG : acyclic_no_loop G
  s0 : VSet.t
  x : V.t
  x0 : V.t
  z : Z
  p : SPath G (V G) x0 (s G)
  ============================
   ({|
      pr1 := {| pr1 := V G; pr2 := {| pr1 := x0; pr2 := s G |} |}; pr2 := p
    |} =
    {|
      pr1 := {| pr1 := s0; pr2 := {| pr1 := x; pr2 := x |} |};
      pr2 := spath_refl G s0 x
    |} ->
    let H := CoreTactics.block in
    sweight p = z ->
    ~ VSet.In x0 (V G) -> let H0 := CoreTactics.block in z = 0)


DEBUG:Going to execute:
simplify * || simplify ?