- @(subset_eq_trans ā¦ (lift_fsubst ā¦))
- [ <structure_append <structure_A_sn <structure_append <structure_L_sn
+ @(subset_eq_trans ā¦ (unwind2_term_fsubst ā¦))
+ [ @fsubst_eq_repl [ // | // ]
+ @(subset_eq_trans ā¦ (unwind2_term_iref ā¦))
+ @(subset_eq_canc_sn ā¦ (lift_term_eq_repl_dx ā¦))
+ [ @unwind2_term_grafted_S /2 width=2 by ex_intro/ | skip ] -Ht1
+ @(subset_eq_trans ā¦ (lift_unwind2_term_after ā¦))
+ @unwind2_term_eq_repl_sn
+(* Note: crux of the proof begins *)
+ >list_append_rcons_sn <reverse_append
+ @(stream_eq_trans ā¦ (tr_compose_uni_dx ā¦))
+ @tr_compose_eq_repl
+ [ <unwind2_rmap_append_pap_closed //
+ | >unwind2_rmap_A_sn <reverse_rcons
+ /2 width=1 by tls_unwind2_rmap_closed/
+ ]
+(* Note: crux of the proof ends *)