fact: Fixpoint rterm (t : term R) := match t with | _^-1 => false | t1 + t2 | t1 * t2 => rterm t1 && rterm t2 | - t1 | t1 *+ _ | t1 ^+ _ => rterm t1 | _ => true end%T.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq) mathcomp(choice fintype finfun bigop prime binomial)