Apply unknownprop_f8cb4609f9c174a593de5a10197e2915f5c1a2d9f32ed8d30c3d30b788bb9e1e with
λ x0 x1 : ι → ι → ι . ∀ x2 x3 x4 x5 . In (setsum x4 x5) (x1 x2 x3) ⟶ In x4 x2.
Let x0 of type ι be given.
Let x1 of type ι be given.
Let x2 of type ι be given.
Let x3 of type ι be given.
Apply unknownprop_576918d9e5f208b0d4afcf7c46d767aab50123519e7ada8ee8e8d0a4883e6b6c with
x0,
λ x4 . x1,
x2,
x3.
The subproof is completed by applying H0.