Let x0 of type ι be given.
Let x1 of type ι → ι be given.
Let x2 of type ι → ο be given.
Let x3 of type ι be given.
Apply unknownprop_dd69a998b284b561e0ac55cfbccb4ed2efee0ed6b6936bb42d2cc2500c49f7d3 with
1cd8e.. x0 x1 x2 x3,
x0,
x1,
x2,
x3.
Let x4 of type ι → ι → ο be given.
The subproof is completed by applying H0.