Nijmegen University chair for Foundations of Mathematics and Computer Science. Site presents papers, courses, talks, and project description.

Professor at Carnegie Mellon University with research interests in mathematical logic, proof theory, formal verification, automated reasoning, and philosophy of mathematics.

Stanford University professor of mathematics and philosophy. Site presents publications, papers, books, photos, and courses.

Professor at the Kurt Gödel Research Center for Mathematical Logic at the University of Vienna specializing in mathematical logic and set theory.