Friday, October 7, 201612:30 pmModel theory seminarGC 6417

# Complexity of classification problems for a class of discretely ordered rings

## Roman Kossak

### The City University of New York

I will give a standard introduction to the theory of Borel reducibility, including some details for non-logicians. The rest of the talk will be about some results in classification problems for countable nonstandard models of arithmetic due to Samuel Coskey and myself.

Roman Kossak is professor of mathematics at The City University of New York, at Bronx Community College and also at the CUNY Graduate Center. He conducts research in mathematical logic, especially in model theory of Peano Arithmetic.