Section MapC.
Variables A B C : Type.

Lemma MapMerge_DomRestrBy_c :
forall (m m':Map A) (m'':Map B),
mapcanon A m ->
mapcanon A m' ->
MapDomRestrBy A B (MapMerge A m m') m'' =
MapMerge A (MapDomRestrBy A B m m'') (MapDomRestrBy A B m' m'').