Set: pp::colors Set: pp::unicode Assumed: f Assumed: g Assumed: Axf1 Assumed: Axfg Assumed: a Assumed: b Axfg : ∀ x : ℕ, g x x = x Axf1 : ∀ x : ℕ, f (f x) = x a trans (congr2 (g a) (Axf1 a)) (Axfg a) false g a a congr2 (g a) (Axf1 a) false a trans (congr2 (g a) (Axf1 a)) (Axfg a) false a trans (congr2 (g a) (Axf1 a)) (Axfg a) false