Let x0 of type ι be given.
Let x1 of type ι → ι → ι be given.
Let x2 of type ι → ο be given.
Let x3 of type ι be given.
Apply unknownprop_d8e00ec5ba81673de38524714c3828d0b91cb7cd5092561f5f554750002f8392 with
60b2c.. x0 x1 x2 x3,
x0,
x1,
x2,
x3.
Let x4 of type ι → ι → ο be given.
The subproof is completed by applying H0.