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 be given.
Let x4 of type ι → ι → ο be given.
Let x5 of type ι → ι → ο be given.
Apply H0 with
λ x6 x7 . x1 = ap x7 0.
Let x6 of type ι → ι → ο be given.
The subproof is completed by applying tuple_5_0_eq with
x1,
encode_b x1 x2,
lam x1 x3,
encode_r x1 x4,
encode_r x1 x5,
λ x7 x8 . x6 x8 x7.