fact: Definition cprD := (lerDl, lerDr, gerDl, gerDl, ltrDl, ltrDr, gtrDl, gtrDl).
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)