Let x0 of type ι be given.
Let x1 of type ι be given.
Apply set_ext with
x0,
x1 leaving 2 subgoals.
Apply tagged_eqE_Subq with
x0,
x1 leaving 2 subgoals.
The subproof is completed by applying H0.
The subproof is completed by applying H2.
Apply tagged_eqE_Subq with
x1,
x0 leaving 2 subgoals.
The subproof is completed by applying H1.
Let x2 of type ι → ι → ο be given.
The subproof is completed by applying H2 with λ x3 x4 . x2 x4 x3.