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