Let x0 of type ι be given.
Let x1 of type ι be given.
Let x2 of type ι be given.
Apply unknownprop_47684d77daf9976982fef9cd65f54cb0f256a9046ee087c4a3bf5f6bf45def6c with
x0,
x1,
x2.
Let x3 of type ι → ι → ο be given.
The subproof is completed by applying H0 with λ x4 x5 . x3 x5 x4.