Steve Simpson's Website

Welcome to my website, last updated July 22, 2024. Please email your comments to

In July 2023 I moved this website from one server to another, so some links may have broken. If you encounter broken links, please bring them to my attention immediately.

My full name is Stephen G. Simpson. I am a senior mathematician affiliated with the Pennsylvania State University and with Vanderbilt University. My title at Penn State is Emeritus Professor of Mathematics. For more than 50 years I have been active in mathematical research and in the mentoring of undergraduates, Ph.D. students, postdocs, and faculty members. In the recent past, my research has been supported by the Simons Foundation, the National Science Foundation, the Templeton Foundation, Penn State's Eberly College of Science, and Vanderbilt's College of Arts and Science.

My principal research areas are mathematical logic and foundations of mathematics:

Recently I have been cited and quoted in the popular science press:

In January 2016 I gave a general-audience public lecture on foundations of mathematics.

Currently I am writing a book entitled Degrees of Unsolvability.

My wife is Padma Raghavan. At Penn State, Padma was the Associate Vice President for Research, the Director of the Institute for CyberScience, and a Distinguished Professor of Computer Science and Engineering. In January 2016 Padma and I moved to Vanderbilt University. At Vanderbilt, Padma is the Vice Provost for Research and Innovation and a Distinguished Professor of Computer Science, while I am a Research Professor of Mathematics.

In May 2016 Padma and I attended a conference in honor of my 70th birthday. There were more than 60 participants.

Contact information:

   mail: Stephen G. Simpson
   Department of Mathematics
   1326 Stevenson Center
   Vanderbilt University
   Nashville, TN 37240, USA