category theorist, working mathematician

I am the Kelly Miller Professor of Mathematics at Johns Hopkins University working on higher category theory, homotopy type theory, and computer formalization. I am currently serving as Director of Graduate Studies.

I’m honored to be an invited sectional speaker in topology at the 2026 International Congress of Mathematicians. My contribution to the ICM Conference Proceedings is an expository article Synthetic perspectives on spaces and categories.

I run the Johns Hopkins Category Theory Seminar and am a co-organizer of the Homotopy Type Theory Electronic Seminar Talks. I was both an organizer and lecturer for the HoTTEST Summer School, the archives of which can now be found on GitHub and on YouTube.

I am a co-host of the n-Category Café and was a founding board member of Spectra, where I now serve on the Board of Trustees.

I am currently a member of the Executive Committee of the AMS Council and serve in that capacity on a number of other AMS committees.

I am a member of the Strategic Advisory Board for the Mathlib Initiative, the Scientific Advisory Board for the Institute for Computer-Aided Reasoning in Mathematics, and the Scientific Review Panel for the Pacific Institute for Mathematical Sciences.

I serve on the editorial boards for Homology, Homotopy, and Applications, the Bulletin of the AMS, and Zeitschrift für Mathematische Logik und Grundlagen der Mathematik. In the past, I have served as an editor at Cahiers de Topologie et Géométrie Différentielle Catégoriques, Journal of Homotopy and Related Structures, the Journal of Pure and Applied Algebra, and Mathematical Logic Quarterly.

There is a fairly large cohort of PhD students at Johns Hopkins who are interested in category theory, abstract homotopy theory, homotopy type theory, and related topics. If you are interested in joining us, more information about graduate admissions can be found here.