Let x0 of type ι be given.
Let x1 of type ι → ι → ο be given.
Let x2 of type ι → ο be given.
Let x3 of type ι be given.
Apply unknownprop_a682f86451138e6f86a2eb74eea9164953f0f7b0e911a34effb4bb575e264816 with
e4ab3.. x0 x1 x2 x3,
x0,
x1,
x2,
x3.
Let x4 of type ι → ι → ο be given.
The subproof is completed by applying H0.