[ * #i #L #l #HLK
/2 width=4 by lift_sort, lift_gref, ex2_2_intro/
elim (lt_or_eq_or_gt i l) #Hil
- /3 width=4 by lift_lref_ge_minus, lift_lref_lt, ex2_2_intro/
+ /4 width=4 by lift_lref_ge_minus, lift_lref_lt, ex2_2_intro, ylt_inj, yle_inj/ (**) (* was /3 width=4/ without inj *)
destruct
elim (lift_total V 0 (i+1)) #W #HVW
elim (lift_split … HVW i i)
lapply (drop_fwd_length_lt2 … HLK)
/4 width=5 by cpy_subst, ylt_yle_trans, ylt_inj/
| #a #I #G #L #V1 #V2 normalize in match (|L.ⓑ{I}V2|); (**) (* |?| does not work *)
+ <yplus_inj >yplus_SO2 >yminus_succ
/2 width=1 by cpy_bind/
| /2 width=1 by cpy_flat/
]
| #I #G #L #K #V #W #i #lt #mt #Hlti #Hilmt #HLK #HVW #T1 #l #m #H #Hllt #Hlmlmt
elim (lift_inv_lref2 … H) -H * #Hil #H destruct [ -V -Hilmt -Hlmlmt | -Hlti -Hllt ]
[ elim (ylt_yle_false … Hllt) -Hllt /3 width=3 by yle_ylt_trans, ylt_inj/
- | elim (le_inv_plus_l … Hil) #Hlim #Hmi
- elim (lift_split … HVW l (i-m+1) ? ? ?) [2,3,4: /2 width=1 by le_S_S, le_S/ ] -Hlim
- #T2 #_ >plus_minus // <minus_minus /2 width=1 by le_S/ <minus_n_n <plus_n_O #H -Hmi
+ | elim (yle_inv_plus_inj2 … Hil) #Hlim #Hmi
+ elim (lift_split … HVW l (i-m+1) ? ? ?) [2,3,4: /2 width=1 by yle_succ_dx, le_S_S/ ] -Hlim
+ #T2 #_ >plus_minus /2 width=1 by yle_inv_inj/ <minus_minus /3 width=1 by le_S, yle_inv_inj/ <minus_n_n <plus_n_O #H -Hmi
@(ex2_intro … H) -H @(cpy_subst … HLK HVW) /2 width=1 by yle_inj/ >ymax_pre_sn_comm // (**) (* explicit constructor *)
]
| #a #I #G #L #W1 #W2 #U1 #U2 #lt #mt #_ #_ #IHW12 #IHU12 #X #l #m #H #Hllt #Hlmlmt