UCalgary Peripatetic Seminar: Robin Cockett

Michael Drazin introduced the idea of a “pseudoinverse” for rings and semigroups in 1961. These inverses categorically are rather special as (like ordinary inverses) they are preserved by all functors when they exist. A category is Drazin when all maps have a Drazin inverse. The aim of the talk is prove that when a category has “expressive” rank it must be Drazin. This provides some examples of Drazin categories … time permitting I will explain how Drazin inverses relate to the Fitting decomposition and the Jordan -Chevalley decomposition.