Let f, g and i be given.
We prove the intermediate
claim Hlub:
R_lub A l.
Set P to be the term
l ∈ R.
Set UB to be the term
∀a : set, a ∈ A → a ∈ R → Rle a l.
Set MIN to be the term
∀u : set, u ∈ R → (∀a : set, a ∈ A → a ∈ R → Rle a u) → Rle l u.
We prove the intermediate
claim Hcore:
P ∧ UB.
An
exact proof term for the current goal is
(andEL (P ∧ UB) MIN Hlub).
We prove the intermediate claim Hub: UB.
An
exact proof term for the current goal is
(andER P UB Hcore).
∎