Let x0 of type ι → ο be given.
Let x1 of type ι be given.
Assume H0: x0 x1.
Let x2 of type (ι → ο) → ι → ο be given.
Assume H1: ∀ x3 : ι → ο . ∀ x4 . x3 x4 ⟶ x2 x3 x4.
Assume H2:
∀ x3 : ι → ο . ∀ x4 : ι → ι . (∀ x5 . x2 (de327.. x3 x5) (x4 x5)) ⟶ x2 x3 (56103.. x4).
Assume H3:
∀ x3 : ι → ο . ∀ x4 x5 . x2 x3 x4 ⟶ x2 x3 x5 ⟶ x2 x3 (57d6a.. x4 x5).
Apply H1 with
x0,
x1.
The subproof is completed by applying H0.