# Differential Schemes and Differential Cohomology (12w2151)

Arriving Friday, June 22 and departing Sunday June 24, 2012

## Organizers

Richard Churchill (The City Univesity of New York and Univesity of Calgary)
Yang Zhang (Univesity of Manitoba)

## Objectives

There are two main objectives. The first is to introduce very recent work on the modernization'' of differential algebra to algebraic geometers/number theorists having little or no acquaintance with the field.
The basic properties of the differential spectrum (DiffSpec'') of a differential ring have now been established in a manner which workers in those areas can quickly grasp, but those ideas need a proper venue for communication. The informal nature of BIRS' workshops, which are familiar to both applicants, would be ideal.

The second objective is to illustrate how algebraic problems which can be solved ''locally'' in terms of differential equations may admit global solutions in terms of differential cohomology. Specifically, very recent work by Ray Hoobler enables one to understand Kolchin's constrained cohomology in terms of the $,Delta$-flat topology, and that should offer new methods to algebraic geometers and number theorists. And of course the interaction of people in those areas with differential algebraists should result is new methods for use by the latter group.