Let x0 of type ι be given.
Let x1 of type ι → ι be given.
Let x2 of type ι be given.
Assume H0: x2 ∈ {x1 x3|x3 ∈ x0}.
Apply ReplE with
x0,
x1,
x2,
∀ x3 : ο . (∀ x4 . x4 ∈ x0 ⟶ x2 = x1 x4 ⟶ x3) ⟶ x3 leaving 2 subgoals.
The subproof is completed by applying H0.
Let x3 of type ι be given.
Assume H1:
(λ x4 . and (x4 ∈ x0) (x2 = x1 x4)) x3.
Apply H1 with
∀ x4 : ο . (∀ x5 . x5 ∈ x0 ⟶ x2 = x1 x5 ⟶ x4) ⟶ x4.
Assume H2: x3 ∈ x0.
Assume H3: x2 = x1 x3.
Let x4 of type ο be given.
Assume H4: ∀ x5 . x5 ∈ x0 ⟶ x2 = x1 x5 ⟶ x4.
Apply H4 with
x3 leaving 2 subgoals.
The subproof is completed by applying H2.
The subproof is completed by applying H3.