Let x0 of type ι be given.
Let x1 of type ι → ι be given.
Let x2 of type ι → ι → ο be given.
Let x3 of type ι be given.
Apply unknownprop_693638c467dbd912f9c0a5e25f509ff870b163d0bee8bdc8c46e43fade85b5a2 with
1bcc7.. x0 x1 x2 x3,
x0,
x1,
x2,
x3.
Let x4 of type ι → ι → ο be given.
The subproof is completed by applying H0.