intros a b p q s Eqd Z0 H'; inversion_clear H'; intros.
absurd (eqT b a); auto.
apply eqT_sym; auto.
apply uniq_plusp with (l := (p, q)); auto.
elim H1; auto.
absurd (eqT a b); auto.
Qed.

(* Specifications: *)
Theorem plusP_inv3b :
forall a b p q s,
eqT a b ->
~ zeroP (A:=A) A0 eqA (n:=n) (plusTerm (A:=A) plusA (n:=n) a b) ->
plusP (pX a p) (pX b q) s ->
s = pX (plusTerm (A:=A) plusA (n:=n) a b) (pluspf p q).