Some of the things I've learned every day since Oct 10, 2016
October 13, 2016Posted by on
A monoid is a group-like structure. It can be regarded as a semigroup with an identity element, or as a group without invertibility.
In category theory, a monoid can also be regarded as a category with a single object, where the morphisms of the category correspond to the elements of the monoid, and composition of morphisms corresponds to the operation of the monoid.