(* Constructions with gr_tl *************************************************)
(*** isid_tl *)
-lemma gr_isi_tl (f): ð\9d\90\88â\9dªfâ\9d« â\86\92 ð\9d\90\88â\9dªâ«±f❫.
+lemma gr_isi_tl (f): ð\9d\90\88â\9dªfâ\9d« â\86\92 ð\9d\90\88â\9dªâ«°f❫.
#f cases (gr_map_split_tl f) * #H
[ /2 width=3 by gr_isi_inv_push/
| elim (gr_isi_inv_next … H) -H //