(* Basic_2A1: includes: lsubr_fwd_drop2_pair *)
lemma lsubr_fwd_drops2_bind:
∀L1,L2. L1 ⫃ L2 →
- â\88\80b,f,I,K2. ð\9d\90\94â\9dªfâ\9d« → ⇩*[b,f] L2 ≘ K2.ⓘ[I] →
+ â\88\80b,f,I,K2. ð\9d\90\94â\9d¨fâ\9d© → ⇩*[b,f] L2 ≘ K2.ⓘ[I] →
∨∨ ∃∃K1. K1 ⫃ K2 & ⇩*[b,f] L1 ≘ K1.ⓘ[I]
| ∃∃K1,W,V. K1 ⫃ K2 & ⇩*[b,f] L1 ≘ K1.ⓓⓝW.V & I = BPair Abst W
| ∃∃J1,J2,K1,V. K1 ⫃ K2 & ⇩*[b,f] L1 ≘ K1.ⓑ[J1]V & I = BUnit J2.
(* Basic_2A1: includes: lsubr_fwd_drop2_abbr *)
lemma lsubr_fwd_drops2_abbr:
∀L1,L2. L1 ⫃ L2 →
- â\88\80b,f,K2,V. ð\9d\90\94â\9dªfâ\9d« → ⇩*[b,f] L2 ≘ K2.ⓓV →
+ â\88\80b,f,K2,V. ð\9d\90\94â\9d¨fâ\9d© → ⇩*[b,f] L2 ≘ K2.ⓓV →
∃∃K1. K1 ⫃ K2 & ⇩*[b,f] L1 ≘ K1.ⓓV.
#L1 #L2 #HL12 #b #f #K2 #V #Hf #HLK2
elim (lsubr_fwd_drops2_bind … HL12 … Hf HLK2) -L2 -Hf // *