Let x0 of type ι be given.
Let x1 of type ι be given.
Let x2 of type ι → ι → ι be given.
Let x3 of type ι → ι → ο be given.
Let x4 of type ι → ο be given.
Let x5 of type ι be given.
Assume H1: x5 ∈ x1.
Apply H0 with
λ x6 x7 . x4 x5 = decode_p (ap x7 3) x5.
Apply tuple_4_3_eq with
x1,
encode_b x1 x2,
encode_r x1 x3,
Sep x1 x4,
λ x6 x7 . x4 x5 = decode_p x7 x5.
Let x6 of type ο → ο → ο be given.
Apply decode_encode_p with
x1,
x4,
x5,
λ x7 x8 : ο . x6 x8 x7.
The subproof is completed by applying H1.