proposition: Lemma big_ord1 R idx (op : @Monoid.law R idx) F : \big[op/idx]_(i < 1) F i = F 0.
proof: Proof. by rewrite big_ord_recl big_ord0 Monoid.mulm1. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool choice eqtype ssrnat seq div) mathcomp(fintype bigop finset prime fingroup) mathcomp(ssralg finalg countalg)