Let x0 of type ι be given.
Let x1 of type ι → ι be given.
Let x2 of type ι → ι be given.
Let x3 of type ι → ι → ο be given.
Apply unknownprop_3ff32330ae0d02c08392250fd92dae345b424e0d2c55fe1cf81eca975dcbfa54 with
942b6.. x0 x1 x2 x3,
x0,
x1,
x2,
x3.
Let x4 of type ι → ι → ο be given.
The subproof is completed by applying H0.