Let x0 of type ι be given.
Let x1 of type ι → ι → ι be given.
Let x2 of type ι → ι be given.
Apply unknownprop_94967784b176f60b5bf438df3a2971cde72407446df861d384c2aae63aae54a8 with
971d3.. x0 x1 x2,
x0,
x1,
x2.
Let x3 of type ι → ι → ο be given.
The subproof is completed by applying H0.