Set: pp::colors Set: pp::unicode Assumed: N Assumed: a Assumed: b Assumed: c Assumed: P Proved: T1 Theorem T1 (f : N → N) (H : P (f a) b (f (f c))) : ∃ x y z : N, P x y z := ExistsIntro (f a) (ExistsIntro b (ExistsIntro (f (f c)) H))