Goal:
  
  G : t
  HG : acyclic_no_loop
  x : V.t
  y : V.t
  z : V.t
  e : EdgeOf x y
  p : PathOf y z
  IHp : weight p <= sweight (simplify2 p)
  F0 : false = true -> VSet.In x (snodes (simplify2 p))
  F1 : ~ VSet.In x (snodes (simplify2 p)) <-> false = false
  ============================
   (e.π1 + weight p <=
    sweight
      (SPath_sub
         (VSetFact.add_s_m eq_refl (y:=nodes p) (snodes_Subset (simplify2 p)))
         (spath_step
            (DisjointAdd_add2 (match F1 with
                               | conj _ x => x
                               end eq_refl)) e (reduce (simplify2 p)))))


DEBUG:Going to execute:
<coq-core.plugins.ssreflect::ssrrewrite@0> $1 $2