proposition: Lemma double_half_le m : m./2.*2 <= m.
proof: Proof. by rewrite -{2}(odd_double_half m) leq_addl. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq path fintype div bigop binomial) mathcomp(prime finset ssralg ssrnum ssrint)