Professor; Associate Chair for Regular Faculty

### About

My recent research is in set theory, topos theory, and theoretical computer science. In set theory, I work on cardinal characteristics of the continuum, ultrafilters and ultraproducts, and the axiom of choice and its consequences. In topos theory, I work primarily on the internal logic, especially as it relates to classifying topoi and to the axiom of choice. In computer science, part of my work is of a general foundational nature, and part is connected with quantum computation, especially the theory of anyons. I have also worked in finite combinatorics.