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.
Apply unknownprop_6fbca1603af3e441530006fc32baaa24da891bac1a0549c355cd4461180c6911 with
b6bd3.. x0 x1 x2,
x0,
x1,
x2.
Let x3 of type ι → ι → ο be given.
The subproof is completed by applying H0.