Apply unknownprop_f8cb4609f9c174a593de5a10197e2915f5c1a2d9f32ed8d30c3d30b788bb9e1e with
λ x0 x1 : ι → ι → ι . ∀ x2 x3 x4 . In x4 (x1 x2 x3) ⟶ In (proj1 x4) x3.
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_90e3c298643df766b84b5eceef5956e9876cb7ac85576c91e0f6a929f73153ed with
x0,
λ x3 . x1,
x2.
The subproof is completed by applying H0.