Let X and Tx be given.
Set R to be the term
∃x y : set, x ∈ X ∧ y ∈ X ∧ x ≠ y.
Set T to be the term
∀A : set, A ⊆ X → A ≠ Empty → (∃upper : set, upper ∈ X ∧ ∀a : set, a ∈ A → order_rel X a upper ∨ a = upper) → ∃lub : set, lub ∈ X ∧ (∀a : set, a ∈ A → order_rel X a lub ∨ a = lub) ∧ (∀bound : set, bound ∈ X → (∀a : set, a ∈ A → order_rel X a bound ∨ a = bound) → order_rel X lub bound ∨ lub = bound).
We prove the intermediate
claim H1:
(((P ∧ Q) ∧ R) ∧ S).
An
exact proof term for the current goal is
(andEL (((P ∧ Q) ∧ R) ∧ S) T Hlin).
We prove the intermediate
claim H2:
((P ∧ Q) ∧ R).
An
exact proof term for the current goal is
(andEL ((P ∧ Q) ∧ R) S H1).
We prove the intermediate
claim HPQ:
(P ∧ Q).
An
exact proof term for the current goal is
(andEL (P ∧ Q) R H2).
An
exact proof term for the current goal is
(andER P Q HPQ).
∎