fact: Fixpoint xelements (m : t) (i : elt) (a: list elt) := match m with | Leaf => a | Node l false r => xelements l i~0 (xelements r i~1 a) | Node l true r => xelements l i~0 (rev i :: xelements r i~1 a) end.
imports: Bool PeanoNat BinPos OrderedType OrderedTypeEx FSetInterface