intros l1 l2 H' H'0; generalize (minuspf_is_minusP l1 l2); intros u1.
apply canonical_minusP with (l1 := l1) (l2 := l2); auto.
Qed.

(* Specifications: *)
Lemma invTerm_eqT_comp :
forall a b : Term A n, eqT a b -> eqT a (invTerm (A:=A) invA (n:=n) b).