> idempotent Roughly speaking, while you do need idempotence for reductions, you do not need it for maps. (Of course, plenty of things don't look quite like r

> idempotent Roughly speaking, while you do need idempotence for reductions, you do not need it for maps. (Of course, plenty of things don't look quite like reductions or maps--or they look like both at once--and each is unique.)