+#f #p #q #t1 #t2 #H0t1
+* #b #n * #Hb #Hn #Ht1 #Ht2
+@(ex1_2_intro âĶ (âb) (âââqâ)) @and4_intro
+[ //
+| #g <lift_rmap_structure <depth_structure
+ >tr_pushs_swap <tr_pap_pushs_le //
+| lapply (in_comp_lift_bi f âĶ Ht1) -Ht1 -H0t1 -Hb -Ht2
+ <lift_path_d_empty_dx //
+| lapply (lift_term_eq_repl_dx f âĶ Ht2) -Ht2 #Ht2
+ @(subset_eq_trans âĶ Ht2) -t2
+ @(subset_eq_trans âĶ (lift_fsubst âĶ))
+ [ <structure_append <structure_A_sn <structure_append <structure_L_sn
+ @fsubst_eq_repl [ // ]
+ @(subset_eq_trans âĶ (lift_iref âĶ))
+ @(subset_eq_canc_sn âĶ (lift_term_eq_repl_dx âĶ))
+ [ @lift_grafted_S /2 width=2 by ex_intro/ | skip ]
+ @(subset_eq_trans âĶ (lift_term_after âĶ))
+ @(subset_eq_canc_dx âĶ (lift_term_after âĶ))
+ @lift_term_eq_repl_sn -t1
+ | //
+ | /2 width=2 by ex_intro/
+ | //
+ ]
+]