proposition: Fact le0x t : [tuple of nseq n \bot] <= t :> n.-tuple T.
proof: Proof. by rewrite leEtprod; apply/forallP => i; rewrite tnth_nseq le0x. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)