fact: Fixpoint split_aux (acc l : list A) (n : nat) : option (list A * list A) := match l, n with | _, 0 => Some (rev' acc, l) | a :: l', S n' => split_aux (a::acc) l' n' | _, _ => None end.
imports: CoLoR(LogicUtil EqUtil RelUtil BoolUtil NatUtil) Coq(Setoid SetoidList FunInd)