Let x0 of type ι be given.
Let x1 of type (ι → ο) → ο be given.
Let x2 of type ι → ι → ι be given.
Let x3 of type ι → ι → ο be given.
Apply unknownprop_b630500b59e94e3837ce5a8709e7dd4319757dbf2e976fd4f202d3a12a13d78b with
dd9fd.. x0 x1 x2 x3,
x0,
x1,
x2,
x3.
Let x4 of type ι → ι → ο be given.
The subproof is completed by applying H0.