Thomas G. Kurtz passed away on Saturday, April 19, 2025. He will be deeply missed by the probability and statistics community and all who knew him.
Tom was born on July 14, 1941, in Kansas City, Missouri. He graduated from La Plata High School in La Plata, Missouri, in 1959. He earned his B.A. degree in Mathematics from the University of Missouri in 1963. He then pursued his Ph.D. in Mathematics at Stanford University, which he completed in 1967 under the supervision of James McGregor (Convergence of Operator Semigroups with Applications to Markov Processes).
In 1967, Tom joined the Department of Mathematics at the University of Wisconsin–Madison, where he remained for his entire career. He became a Professor of Mathematics in 1975 and received a joint appointment in the Statistics department in 1985. He served as the Mathematics Department Chair from 1985 to 1988 and as the Director of the Center for Mathematical Sciences from 1990 to 1996. In 1996, he was awarded the WARF-University Houses Professorship, which he chose to identify as the Paul Lévy Professorship to honor one of the founders of modern probability theory. Tom retired from active teaching in 2008 but continued to work as an emeritus professor.
Tom’s research focused on the convergence, approximation, and representation of several important classes of Markov processes. His findings have had a significant impact on various scientific disciplines, including systems biology, population genetics, telecommunications networks, and mathematical finance. Over his career, he published over 100 peer-reviewed articles (with three of them appearing in 2024!) and authored four books. His book titled Markov processes (joint with his former graduate student, Stewart Ethier) is one of the foundational works on the subject. Tom supervised 29 Ph.D. students and organized a Summer Internship Program in Probability in Madison for nearly a decade, significantly impacting a large number of probabilists.
Tom was a Fellow of the Institute of Mathematical Statistics, the American Academy of Arts and Sciences, and the American Mathematical Society. He served as the President of the Institute of Mathematical Statistics (2005-2006) and as the Editor of the Annals of Probability (2000-2002). He held several visiting positions around the world, including at Imperial College London, Goethe University Frankfurt, and the Isaac Newton Institute for Mathematical Sciences. He was also a trustee of the Mathematical Biosciences Institute in Columbus, Ohio.
Tom Kurtz was known for his dedication to his profession and his students. He was always generous with his time and expertise, he was an incredible resource for all things related to probability, and will be greatly missed.