# nLab monad (disambiguation)

Various concepts go by the name monad.

Historically, going back to Gottfried Leibniz, “monad” is used to refer to a kind of “atom”, for him a mind-like simple substance. Derived from this is the idea of an “atom of space” (see also in Science of Logic the section The Monad of Leibniz). In roughly this sense the term is used in

In category theory and computer science a monad is a monoid acting on a category/type system, see at

To see this as an “atom” one observes that this is equivalently a lax 2-functor $\ast \longrightarrow Cat$ from the terminal category to the 2-category of categories and hence a "point" in some 2-categorical sense.

category: disambiguation

Revised on December 4, 2013 04:55:05 by Mike Shulman (172.10.15.11)