Friday, November 1, 201310:00 amSet theory seminarGC 6417

# Some problems motivated by nonstandard set theory

## Karel Hrbacek

### City College of New York, CUNY

Nonstandard set theory enriches the usual set theory by a unary “standardness” predicate. Investigations of its foundations raise a number of questions that can be formulated in ZFC or GB and appear open. I will discuss several such problems concerning elementary embeddings, ultraproducts, ultrafilters and large cardinals.

Professor Hrbacek undertakes research in the area of mathematical logic, particularly in set theory, with a focus on non-standard analysis and nonstandard set theory. He wrote in co-authorship with Thomas Jech the highly regarded book Introduction to Set Theory.