Let t be given.
We prove the intermediate
claim HtR:
t ∈ R.
We prove the intermediate
claim Hconj:
¬ (Rlt t 0) ∧ ¬ (Rlt 1 t).
An
exact proof term for the current goal is
(SepE2 R (λx0 : set ⇒ ¬ (Rlt x0 0) ∧ ¬ (Rlt 1 x0)) t HtI).
We prove the intermediate
claim Hnlt:
¬ (Rlt 1 t).
An
exact proof term for the current goal is
(andER (¬ (Rlt t 0)) (¬ (Rlt 1 t)) Hconj).
An
exact proof term for the current goal is
(RleI t 1 HtR real_1 Hnlt).
∎