proposition: Lemma FM_recd2 n: FMd (n.+1) = (FMd n).*2 + (odd n).
proof: Proof. by rewrite - addnn - addnA - FM_recE1 addnC FM_dE. 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)