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_bea58743470cf59c08328c25b67914c6bf432a0320ac293addf7e1d3e82c00ba 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.