Let x0 of type ι be given.
Apply unknownprop_ea78574cb3264467ecb0cee6dab0f2cbbdf0e0a00f843238d57e1be6acdbe25f with
f482f.. 4a7ef.. x0.
Let x1 of type ι be given.
Apply unknownprop_36581520bffccb98b6c3f6da561f1dee9f6d78d0af9fec9a0855f273170722c3 with
4a7ef..,
x0,
x1.
The subproof is completed by applying H0.