apply ArrayType.ext (Idx:=Idx)
Cont : Type u_2
Idx : outParam (Type u_3)
Elem : outParam (Type u_1)
inst✝⁴ : IndexType Idx
inst✝³ : outParam (DecidableEq Idx)
inst✝² : LawfulIndexType Idx
inst✝¹ : ArrayType Cont Idx Elem
inst✝ : Add Elem
f g : Idx → Elem
⊢ Indexed.ofFn f + Indexed.ofFn g = Indexed.ofFn fun i => f i + g i
case a
Cont : Type u_2
Idx : outParam (Type u_3)
Elem : outParam (Type u_1)
inst✝⁴ : IndexType Idx
inst✝³ : outParam (DecidableEq Idx)
inst✝² : LawfulIndexType Idx
inst✝¹ : ArrayType Cont Idx Elem
inst✝ : Add Elem
f g : Idx → Elem
⊢ ∀ (i : Idx), (Indexed.ofFn f + Indexed.ofFn g)[i] = (Indexed.ofFn fun i => f i + g i)[i]