[ /2 width=1 by sta_lstasa/
| #G #L #l #k #X #H >(sta_inv_sort1 … H) -X >commutative_plus //
| #G #L #K #V #W #U #i #l #HLK #_ #HWU #IHVW #U2 #HU2
- lapply (ldrop_fwd_drop2 … HLK) #H
+ lapply (drop_fwd_drop2 … HLK) #H
elim (sta_inv_lift1 … HU2 … H … HWU) -H -U /3 width=6 by lstasa_ldef/
| #G #L #K #W #V #V0 #U #i #l #HLK #HWl0 #_ #HVU #IHWV #U2 #HU2
- lapply (ldrop_fwd_drop2 … HLK) #H
+ lapply (drop_fwd_drop2 … HLK) #H
elim (sta_inv_lift1 … HU2 … H … HVU) -H -U /3 width=8 by lstasa_ldec/
| #a #I #G #L #V #T1 #U1 #l #_ #IHTU1 #X #H
elim (sta_inv_bind1 … H) -H #U #HU1 #H destruct /3 width=1 by lstasa_bind/