# Witt vectors, Lambda-rings, and absolute algebraic geometry

*Algebra/Geometry/Topology Seminar*

*by Jim Borger*

*Institution:*ANU

*Date: Fri 6th February 2009*

*Time: 2:30 PM*

*Location: JH Michell Theatre*

*Abstract*: I will explain how the closely related concepts of Witt vector and Lambda-ring give rise to a kind of algebraic geometry that is, in a precise sense, over a deeper base than the ring of integers, the usual base in arithmetic algebraic geometry. I will also say something about how this related to other issues in arithmetic algebraic geometry.

*For More Information:* S.Tillmann@ms.unimelb.edu.au