Apply unknownprop_f8cb4609f9c174a593de5a10197e2915f5c1a2d9f32ed8d30c3d30b788bb9e1e with
λ x0 x1 : ι → ι → ι . ∀ x2 x3 x4 . In x4 (x1 x2 x3) ⟶ In (proj0 x4) x2.
Let x0 of type ι be given.
Let x1 of type ι be given.
Let x2 of type ι be given.
Assume H0:
In x2 (lam x0 (λ x3 . x1)).
Apply unknownprop_5602d478ac2925d3761ba3ec5f78288f7907f59db6d1b15212dcf9b70f55d5f8 with
x0,
λ x3 . x1,
x2.
The subproof is completed by applying H0.