proposition: Lemma half_le1 m: m./2 <= m.
proof: Proof. by rewrite -{2}(odd_double_half m) -addnn addnA leq_addl. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq path fintype div bigop binomial) mathcomp(prime finset ssralg ssrnum ssrint)