Let x0 of type ι be given.
Claim L1:
ap x0 0 ∈ u6
Apply ap0_Sigma with
u6,
λ x1 . u6,
x0.
The subproof is completed by applying H0.
Apply ap1_Sigma with
u6,
λ x1 . u6,
x0.
The subproof is completed by applying H0.
Apply unknownprop_72649fc0d609625e17ac53e25cd57a51abe86f395cd11e949eac34127a9e2ea9 with
ap x0 0,
λ x1 x2 . lam 2 (λ x3 . If_i (x3 = 0) x2 (Church6_to_u6 (nth_6_tuple (ap x0 u1)))) = x0 leaving 2 subgoals.
The subproof is completed by applying L1.
Apply unknownprop_72649fc0d609625e17ac53e25cd57a51abe86f395cd11e949eac34127a9e2ea9 with
ap x0 u1,
λ x1 x2 . lam 2 (λ x3 . If_i (x3 = 0) (ap x0 0) x2) = x0 leaving 2 subgoals.
The subproof is completed by applying L2.
Apply tuple_Sigma_eta with
u6,
λ x1 . u6,
x0.
The subproof is completed by applying H0.