Let x0 of type ι be given.
Let x1 of type ι be given.
Apply andI with
x0 ∈ x1,
∀ x2 . x2 ∈ x1 ⟶ x2 = x0 leaving 2 subgoals.
Apply H0 with
λ x2 x3 . x0 ∈ x2.
The subproof is completed by applying SingI with x0.
Let x2 of type ι be given.
Apply H0 with
λ x3 x4 . x2 ∈ x3 ⟶ x2 = x0.
Apply SingE with
x0,
x2.
The subproof is completed by applying H1.