Let x0 of type ο be given.
Apply H0 with
λ x1 . pack_u (setsum x1 x1) (combine_funcs x1 x1 Inj1 Inj1).
Let x1 of type ο be given.
Apply H1 with
λ x2 x3 x4 . lam (setsum x2 x2) (λ x5 . combine_funcs x2 x2 (λ x6 . Inj0 (ap x4 x6)) (λ x6 . Inj1 (ap x4 x6)) x5).
Let x2 of type ο be given.
Apply H2 with
λ x3 . lam x3 (λ x4 . Inj0 x4).
Let x3 of type ο be given.
Apply H3 with
λ x4 . unpack_u_i x4 (λ x5 . λ x6 : ι → ι . lam (setsum x5 x5) (λ x7 . combine_funcs x5 x5 (λ x8 . x8) x6 x7)).
The subproof is completed by applying unknownprop_cc47c963ab9cc0e5e798780a66a4301b5c1e3c6b4bcc2abf1af8a16f9b487402.