Goal:
  
  __x1 : Z
  __wit := [] : list ZMicromega.ZArithProof
  __varmap := VarMap.Elt __x1 : VarMap.t Z
  __ff := Tauto.A Tauto.isProp
            {|
              RingMicromega.Flhs :=
                EnvRing.PEadd (EnvRing.PEopp (EnvRing.PEX 1)) (EnvRing.PEc 0);
              RingMicromega.Fop := RingMicromega.OpEq;
              RingMicromega.Frhs := EnvRing.PEopp (EnvRing.PEX 1)
            |} tt : Tauto.BFormula (RingMicromega.Formula Z) Tauto.isProp
  ============================
   (- __x1 + 0 = - __x1)


DEBUG:Going to execute:
exact
(ZMicromega.ZTautoChecker_sound __ff __wit
   (eq_refl <: ZMicromega.ZTautoChecker __ff __wit = true)
   (VarMap.find 0 __varmap))