Ivo Herzog, Ohio State University
Examples of Ring Epimorphisms

Abstract: I will give two kinds of examples of ring epimorphisms from a ring R. The first family of examples are more familiar and include commutative localization at a multiplicative monoid. They arise from formal adjunction of elements that are solutions to equations that have at most one solution in any R-ring. The other class arises from picking a definable subcategory of R-Mod whose R-ring of definable scalars is epic. This kind of example includes the Cohn spectrum of R and the finite dimensional representations of sl(2,k). The talk partly relies on joint work with Sonia L’Innocente.