(* Basic inversions *********************************************************)
(*** isid_inv_gen *)
-lemma pr_isi_inv_gen (g): ð\9d\90\88â\9dªgâ\9d« â\86\92 â\88\83â\88\83f. ð\9d\90\88â\9dªfâ\9d« & ⫯f = g.
+lemma pr_isi_inv_gen (g): ð\9d\90\88â\9d¨gâ\9d© â\86\92 â\88\83â\88\83f. ð\9d\90\88â\9d¨fâ\9d© & ⫯f = g.
#g * -g
#f #g #Hf /2 width=3 by ex2_intro/
qed-.
(* Advanced inversions ******************************************************)
(*** isid_inv_push *)
-lemma pr_isi_inv_push (g): ð\9d\90\88â\9dªgâ\9d« â\86\92 â\88\80f. ⫯f = g â\86\92 ð\9d\90\88â\9dªfâ\9d«.
+lemma pr_isi_inv_push (g): ð\9d\90\88â\9d¨gâ\9d© â\86\92 â\88\80f. ⫯f = g â\86\92 ð\9d\90\88â\9d¨fâ\9d©.
#g #H
elim (pr_isi_inv_gen … H) -H #f #Hf
* -g #g #H
qed-.
(*** isid_inv_next *)
-lemma pr_isi_inv_next (g): ð\9d\90\88â\9dªgâ\9d« → ∀f. ↑f = g → ⊥.
+lemma pr_isi_inv_next (g): ð\9d\90\88â\9d¨gâ\9d© → ∀f. ↑f = g → ⊥.
#g #H
elim (pr_isi_inv_gen … H) -H #f #Hf
* -g #g #H elim (eq_inv_pr_next_push … H)