For example, collections can be zipped if and only if the monad's endofunctor preserves pullbacks.
The next result establishes constraints for any equational presentation of a zipped monad.
These 'centrally zipped' palisades appear to play a role in inhibiting water penetration.
In particular, zipped monads are closed under cartesian submonads.
Shape amounts to length and two lists of the same length are zipped in the usual way.
Our next task is to establish some facts about the relationship between shapely, shaped and zipped monads.
They were perfect for this situation; they sort of folded in on themselves and could be zipped into a pouch.
The following corollary slows that this cannot happen for zipped monads.
