apply Classical.axiomOfChoice
A✝ : Type
R : A✝ → A✝ → Prop
inhabited_A : Nonempty A✝
A : Sort u_1
Q : A → A → Prop
a : A
forall_exists_Q : ∀ (a : A), ∃ b, Q a b
⊢ ∃ f, ∀ (x : A), Q x (f x)
case h
A✝ : Type
R : A✝ → A✝ → Prop
inhabited_A : Nonempty A✝
A : Sort u_1
Q : A → A → Prop
a : A
forall_exists_Q : ∀ (a : A), ∃ b, Q a b
⊢ ∀ (x : A), ∃ y, Q x y