-| ldrop_atom: ∀d,e. ldrop d e (⋆) (⋆)
-| ldrop_pair: ∀L,I,V. ldrop 0 0 (L. 𝕓{I} V) (L. 𝕓{I} V)
-| ldrop_ldrop: ∀L1,L2,I,V,e. ldrop 0 e L1 L2 → ldrop 0 (e + 1) (L1. 𝕓{I} V) L2
-| ldrop_skip: ∀L1,L2,I,V1,V2,d,e.
- ldrop d e L1 L2 → ↑[d,e] V2 ≡ V1 →
- ldrop (d + 1) e (L1. 𝕓{I} V1) (L2. 𝕓{I} V2)
+| ldrop_atom : ∀d,e. ldrop d e (⋆) (⋆)
+| ldrop_pair : ∀L,I,V. ldrop 0 0 (L. ⓑ{I} V) (L. ⓑ{I} V)
+| ldrop_ldrop: ∀L1,L2,I,V,e. ldrop 0 e L1 L2 → ldrop 0 (e + 1) (L1. ⓑ{I} V) L2
+| ldrop_skip : ∀L1,L2,I,V1,V2,d,e.
+ ldrop d e L1 L2 → ⇧[d,e] V2 ≡ V1 →
+ ldrop (d + 1) e (L1. ⓑ{I} V1) (L2. ⓑ{I} V2)