Jonathan L. Alperin *61

At age 88, Jon died June 22, 2025, in Chicago.

Jon was born in Boston, June 2, 1937. He completed his undergraduate studies at Harvard in 1959 and earned a Ph.D. in mathematics from Princeton in 1961. He was a postdoc at Oxford.

Jon was a professor of mathematics at the University of Chicago and a visitor at the Institute for Advanced Study. His dissertation, “On a Special Class of Regular p-groups,” marked the beginning of an interest in groups of prime power order that culminated in a collaboration with George Glauberman, establishing an existence criterion for such groups to have abelian normal subgroups of prescribed size.

The Alperin Fusion Theorem, the main result of his 1967 paper “Sylow intersections and fusion,” makes precise the sense in which conjugation can always be understood locally and allows for a unified treatment of several nonsimplicity criteria.

In 1986, Jon announced Alperin’s Weight Conjecture, identifying a simple way in which the number of irreducible representations of a finite group in positive characteristic is determined locally. Many consider this to be one of the major currently outstanding problems in the theory of 
finite groups.

Jon is survived by his nephew, Greg, and his niece, Courtney.

Graduate memorials are prepared by the APGA.