Let x0 of type ι → ο be given.
Assume H0: ∀ x1 . x0 x1 ⟶ ∀ x2 . x2 ⊆ x1 ⟶ x0 x2.
Let x1 of type ο be given.
Apply H1 with
λ x2 x3 x4 x5 . {x6 ∈ x3|quotient (3897e.. x2 x4 x5) x6}.
Let x2 of type ο be given.
Apply H2 with
λ x3 x4 x5 x6 . lam x4 (λ x7 . canonical_elt (3897e.. x3 x5 x6) x7).
Let x3 of type ο be given.
Apply H3 with
λ x4 x5 x6 x7 x8 x9 . lam {x10 ∈ x5|quotient (3897e.. x4 x6 x7) x10} (λ x10 . ap x9 x10).
Let x4 of type ι be given.
Let x5 of type ι be given.
Assume H4: x0 x4.
Assume H5: x0 x5.
Let x6 of type ι be given.
Let x7 of type ι be given.