proposition: Lemma splitD (x y e : F) : x < e / 2%:R -> y < e / 2%:R -> x + y < e.
proof: Proof. by move=> hx hy; rewrite [e](splitf 2) ltr_add. Qed.
imports: mathcomp.ssreflect.ssreflect mathcomp(ssrfun ssrbool eqtype ssrnat seq choice fintype) mathcomp(bigop order ssralg ssrnum ssrint rat poly polydiv polyorder) mathcomp(perm matrix mxpoly polyXY binomial bigenough)