Categorification in representation theory

Abstract: 

This will be an expository talk concerning the idea of categorification and its role in representation theory.  We will begin with some very simple yet beautiful observations about how various ideas from basic algebra (monoids, groups, rings, representations etc.) can be reformulated in the language of category theory.  We will then explain how this viewpoint leads to new ideas such as the "categorification" of the above-mentioned algebraic objects.  We will conclude with a brief synopsis of some current active areas of research, including the categorification of quantum groups.  One of the goals of this idea is to produce four-dimensional topological quantum field theories.  Very little background knowledge will be assumed and the talk should be accessible to graduate students.