proposition: Lemma T1finite2 x: T1finite x -> T1nf x -> x = \F ((T1split x).2).
proof: Proof. by case: x => // a n b /eqP -> /T1nf_finite ->. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(fintype bigop)