Let x0 of type ι be given.
Let x1 of type ι be given.
Apply unknownprop_3189570886a432a72e87efcbd0ea995fafcd88c6ec3c7fdffceb2e344a826cdc with
setsum x0 x1,
λ x2 x3 . x2 = x0.
The subproof is completed by applying unknownprop_e2d9dae0ea3a0bd6555cf6ae3b66e91e8730bfc402bf8dbafcc7b19c9adfb426 with x0, x1.