End MapSweepDef.
Variable B : Type.
Fixpoint MapCollect1 (f:ad -> A -> Map B) (pf:ad -> ad)
(m:Map A) {struct m} : Map B :=
match m with
| M0 => M0 B
| M1 a y => f (pf a) y
| M2 m1 m2 =>
MapMerge B (MapCollect1 f (fun a0:ad => pf (Ndouble a0)) m1)
(MapCollect1 f (fun a0:ad => pf (Ndouble_plus_one a0)) m2)
end.
Definition MapCollect (f:ad -> A -> Map B) (m:Map A) :=
MapCollect1 f (fun a:ad => a) m.
Section MapFoldDef.
Variable M : Type.
Variable neutral : M.
Variable op : M -> M -> M.
Fixpoint MapFold1 (f:ad -> A -> M) (pf:ad -> ad)
(m:Map A) {struct m} : M :=
match m with
| M0 => neutral
| M1 a y => f (pf a) y
| M2 m1 m2 =>
op (MapFold1 f (fun a0:ad => pf (Ndouble a0)) m1)
(MapFold1 f (fun a0:ad => pf (Ndouble_plus_one a0)) m2)
end.
Definition MapFold (f:ad -> A -> M) (m:Map A) :=
MapFold1 f (fun a:ad => a) m.

Lemma MapFold_empty : forall f:ad -> A -> M, MapFold f (M0 A) = neutral.