proposition: Lemma fgequivP rD1 rD2 : reflect (precoeff^~ rD1 =1 precoeff^~ rD2) (fgequiv rD1 rD2).
proof: Proof. by case: rD1 rD2 => [s1 HD1] [s2 HD2]; apply/freegequivP. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop order generic_quotient) mathcomp(ssralg ssrnum ssrint)