proposition: Lemma big_seq1 I (i : I) F : \big[*%M/1]_(j <- [:: i]) F j = F i.
proof: Proof. by rewrite big_seq1_id mulm1. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq path) mathcomp(div fintype tuple finfun)