- @(subset_eq_trans … (lift_fsubst …))
- [ <structure_append <structure_A_sn <structure_append <structure_L_sn
- @fsubst_eq_repl [ // ]
- @(subset_eq_trans … (lift_iref …))
+ @(subset_eq_trans … (unwind2_term_fsubst …))
+ [ @fsubst_eq_repl [ // | // ]
+ @(subset_eq_trans … (unwind2_term_iref …))
+ @(subset_eq_canc_sn … (lift_term_eq_repl_dx …))
+ [ @unwind2_term_grafted_S /2 width=2 by ex_intro/ | skip ] -Ht1
+ @(subset_eq_trans … (unwind2_lift_term_after …))
+ @unwind2_term_eq_repl_sn
+(* Note: crux of the proof begins *)
+ @nstream_eq_inv_ext #m
+ <tr_compose_pap <tr_compose_pap
+ <tr_uni_pap <tr_uni_pap <tr_pap_plus
+ >list_append_rcons_sn in H1n; <reverse_append #H1n
+ lapply (unwind2_rmap_append_pap_closed f … H1n) #H2n
+ >nrplus_inj_dx in ⊢ (???%); <H2n -H2n
+ lapply (tls_unwind2_rmap_append_closed f … H1n) #H2n
+ <(tr_pap_eq_repl … H2n) -H2n -H1n //
+(* Note: crux of the proof ends *)