proposition: Lemma fgoner_eq0 : fgone != 0.
proof: Proof. by apply/eqP/malgP=> /(_ 1%M) /eqP; rewrite !mcoeffsE oner_eq0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq path choice finset fintype finfun) mathcomp(tuple bigop ssralg ssrint ssrnum) xfinmap