intros Q p q r s H'; generalize r s; clear r s; elim H'; auto.
intros x y H'0 r s H'1 H'2 H'3.
apply Rstar_0; auto.
apply (eqp_trans _ _ _ _ _ _ _ _ _ cs n) with (y := y); auto.
apply (eqp_trans _ _ _ _ _ _ _ _ _ cs n) with (y := x); auto.
apply (eqp_sym _ _ _ _ _ _ _ _ _ cs n); auto.
intros x y z H'0 H'1 H'2 r s H'3 H'4 H'5.
apply Rstar_n with (y := y); auto.
apply reduce_eqp_com with (1 := cs) (p := x) (q := y); auto.
apply H'2; auto.
apply canonical_reduce with (1 := cs) (3 := H'0); auto.
Qed.

Theorem reduceplus_trans :
forall (Q : list (poly A0 eqA ltM)) (x y z : list (Term A n)),
reduceplus Q x y ->
canonical A0 eqA ltM x -> reduceplus Q y z -> reduceplus Q x z.