Let x0 of type ι be given.
Let x1 of type ι be given.
Apply set_ext with
UPair x0 x1,
UPair x1 x0 leaving 2 subgoals.
The subproof is completed by applying unknownprop_41df03d7391f8ab64a94521b5b73d37be1e15da3e6364796447f828200c63f8e with x0, x1.
The subproof is completed by applying unknownprop_41df03d7391f8ab64a94521b5b73d37be1e15da3e6364796447f828200c63f8e with x1, x0.