(* Specific inversion lemmas ************************************************)
-lemma isid_inv_seq: ∀f,n. 𝐈⦃n@f⦄ → 𝐈⦃f⦄ ∧ 0 = n.
+lemma isid_inv_seq: ∀f,n. 𝐈⦃n⨮f⦄ → 𝐈⦃f⦄ ∧ 0 = n.
#f #n #H elim (isid_inv_gen … H) -H
#g #Hg #H elim (push_inv_seq_dx … H) -H /2 width=1 by conj/
qed-.