Let x0 of type ι be given.
Let x1 of type ι → ι → ι be given.
Let x2 of type ι → ι → ι be given.
Let x3 of type ι → ο be given.
Apply unknownprop_5dc5e64cc3d57eb67f0a00b204aa76f4c01bd793b07f2c1d1380c9e8cedb2543 with
8f64a.. x0 x1 x2 x3,
x0,
x1,
x2,
x3.
Let x4 of type ι → ι → ο be given.
The subproof is completed by applying H0.