- ∨∨ ∃∃V2,T2. V1 ➡ V2 & U0 ➡ T2 &
- U2 = ⓕ{I} V2. T2
- | ∃∃V2,W,T1,T2. V1 ➡ V2 & T1 ➡ T2 &
- U0 = ⓛW. T1 &
- U2 = ⓓV2. T2 & I = Appl
- | ∃∃V2,V,W1,W2,T1,T2. V1 ➡ V2 & W1 ➡ W2 & T1 ➡ T2 &
- ⇧[0,1] V2 ≡ V &
- U0 = ⓓW1. T1 &
- U2 = ⓓW2. ⓐV. T2 &
- I = Appl
- | (U0 ➡ U2 ∧ I = Cast).
+ ∨∨ ∃∃V2,T2. V1 ➡ V2 & U0 ➡ T2 &
+ U2 = ⓕ{I} V2. T2
+ | ∃∃a,V2,W,T1,T2. V1 ➡ V2 & T1 ➡ T2 &
+ U0 = ⓛ{a}W. T1 &
+ U2 = ⓓ{a}V2. T2 & I = Appl
+ | ∃∃a,V2,V,W1,W2,T1,T2. V1 ➡ V2 & W1 ➡ W2 & T1 ➡ T2 &
+ ⇧[0,1] V2 ≡ V &
+ U0 = ⓓ{a}W1. T1 &
+ U2 = ⓓ{a}W2. ⓐV. T2 &
+ I = Appl
+ | (U0 ➡ U2 ∧ I = Cast).