Definition Qeval_formula (e:PolEnv Q) (k: Tauto.kind) (ff : Formula Q) :=
  let (lhs,o,rhs) := ff in Qeval_op2 k o (Qeval_expr e lhs) (Qeval_expr e rhs).Definition Qeval_formula' :=
  eval_formula  Qplus Qmult Qminus Qopp Qeq Qle Qlt (fun x => x) (fun x => x) (pow_N 1 Qmult).

Lemma Qeval_formula_compat : forall env b f, Tauto.hold b (Qeval_formula env b f) <-> Qeval_formula' env f.