Let x0 of type ι be given.
Let x1 of type ι → ι → ι be given.
Assume H0:
∀ x2 . prim1 x2 x0 ⟶ ∀ x3 . prim1 x3 x0 ⟶ prim1 (x1 x2 x3) x0.
Let x2 of type ι → ι be given.
Assume H1:
∀ x3 . prim1 x3 x0 ⟶ prim1 (x2 x3) x0.
Let x3 of type ι → ι → ο be given.
Let x4 of type ι → ι → ο be given.
Let x5 of type ι → ο be given.
Assume H2:
∀ x6 . ∀ x7 : ι → ι → ι . (∀ x8 . prim1 x8 x6 ⟶ ∀ x9 . prim1 x9 x6 ⟶ prim1 (x7 x8 x9) x6) ⟶ ∀ x8 : ι → ι . (∀ x9 . prim1 x9 x6 ⟶ prim1 (x8 x9) x6) ⟶ ∀ x9 x10 : ι → ι → ο . x5 (d0dcf.. x6 x7 x8 x9 x10).
Apply H2 with
x0,
x1,
x2,
x3,
x4 leaving 2 subgoals.
The subproof is completed by applying H0.
The subproof is completed by applying H1.