proposition: Lemma Sba_pK: cancel Sba_p Sba_m.
proof: Proof. by move => x; rewrite /Sba_p /Sba_m addrAC subrr add0r. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq choice fintype order bigop ssralg) mathcomp(div ssrnum ssrint rat prime path binomial) mathcomp(tuple finset) gaia(fibm)