fact: Definition one_root2 (p : {poly R}) (a : R) := { ck | [/\ (a < ck.1) && (0 < ck.2), (neg_in_interval2 a ck.1 (horner p)) & (slope_bounded ck.1 ck.2 (horner p))] }.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice fintype order) mathcomp(binomial bigop ssralg poly ssrnum ssrint rat) mathcomp(polyrcf) pol