Let x and y be given.
Set P to be the term
(λr : set ⇒ R_lub A r).
We prove the intermediate
claim HAinR:
∀a : set, a ∈ A → a ∈ R.
We prove the intermediate
claim Hub:
∃u : set, u ∈ R ∧ ∀a : set, a ∈ A → a ∈ R → Rle a u.
We prove the intermediate
claim HAnen:
∃a0 : set, a0 ∈ A.
We prove the intermediate
claim H0omega:
0 ∈ ω.
We prove the intermediate
claim Hex:
∃l : set, P l.
An
exact proof term for the current goal is
(R_lub_exists A HAnen HAinR Hub).
An
exact proof term for the current goal is
(Eps_i_ex P Hex).
∎