Let x0 of type ι be given.
Let x1 of type ι → ι → ι be given.
Apply unknownprop_7aec93233696102c2436f4a8c96f0327308c9d3339e09de38f55e901e0baed22 with
987b2.. x0 x1,
x0,
x1.
Let x2 of type ι → ι → ο be given.
The subproof is completed by applying H0.