Let x0 of type ι → ι be given.
Let x1 of type ι → ι be given.
Assume H0:
not (x0 = x1).
Assume H1:
f8922.. (λ x2 : ι → ι . or (x2 = x0) (x2 = x1)).
Let x2 of type ι be given.
Let x3 of type ο be given.
Assume H3: x3.
The subproof is completed by applying H3.