Let x0 of type ι be given.
Let x1 of type (ι → ο) → ο be given.
Let x2 of type ι → ο be given.
Apply unknownprop_359c5637377bb4b5656a8b5c4c2ec57fd8816c736e7cae5b4a8d88e2d60b9299 with
01d88.. x0 x1 x2,
x0,
x1,
x2.
Let x3 of type ι → ι → ο be given.
The subproof is completed by applying H0.