fact: Fixpoint iter2_aux k n p q i (s : seq A) := if k is k1.+1 then if i + q < n then iter2_aux k1 n p q i.+1 (if odd (i %/ p) then s else swap (i + p) (i + q) s) else s else s.
imports: mathcomp(all_ssreflect perm algebra.zmodp) mathcomp(zify) more_tuple nsort