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_d2499cb12676fe01afc1a77dbe72b7961a2da377ad80002ad667e548d5605bae 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.