Let x0 of type ι be given.
Let x1 of type ι be given.
Let x2 of type (ι → ο) → ο be given.
Let x3 of type ι → ι → ι be given.
Let x4 of type ι be given.
Let x5 of type ι be given.
Let x6 of type ι → ο be given.
Assume H1: ∀ x7 . x6 x7 ⟶ x7 ∈ x1.
Apply H0 with
λ x7 x8 . x2 x6 = decode_c (ap x8 1) x6.
Apply tuple_5_1_eq with
x1,
encode_c x1 x2,
encode_b x1 x3,
x4,
x5,
λ x7 x8 . x2 x6 = decode_c x8 x6.
Let x7 of type ο → ο → ο be given.
Apply decode_encode_c with
x1,
x2,
x6,
λ x8 x9 : ο . x7 x9 x8.
The subproof is completed by applying H1.