fact: Definition accr_neg p (a r : F) := ({ k | 0 < k & forall x y, (x != y)%B -> `|x - a| <= r -> `|y - a| <= r -> (p.[x] - p.[y]) / (x - y) < - k} * forall x, `|x - a| <= r -> p^`().[x] < 0)%type.
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)