proposition: Lemma Rank1K i0 (k : 'I_(p_ i0)) : sig1 (Rank k) = i0.
proof: Proof. by rewrite /sig1 /Rank/= rankK/=. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)