Irving Martin Isaacs (April 14, 1940 – 2025) was an American group theorist and representation theorist. He was a professor of mathematics at the University of Wisconsin–Madison until his retirement.[1][2][3][4]
Isaacs was born in the Bronx, in New York City, on April 14, 1940.[5][6] He received a BS from the Polytechnic Institute of Brooklyn in 1960.[6]
Isaacs went on to Harvard University for graduate study. He received a masters degree in 1961,[6] and completed his PhD in 1964. His thesis was advised by Richard Brauer,[7] and was titled Finite -solvable linear groups.[8] After a few years at the University of Chicago as an instructor and visiting assistant professor, Isaacs moved to the University of Wisconsin–Madison in 1969.[6] He was hired as an associate professor, and promoted to full professor in 1971.[6] According to the Mathematics Genealogy Project, he supervised 29 doctoral students over his career.[7]
In 2011, Isaacs retired and became a professor emeritus.[1][2][3][4] In retirement, he lived in Berkeley, California and was an occasional participant on MathOverflow.[4]
Isaacs is most famous for formulating the Isaacs–Navarro conjecture along with Gabriel Navarro, a widely cited generalization of the McKay conjecture.[9][10]
Isaacs is famous as the author of Character Theory of Finite Groups (first published in 1976), one of the most well-known graduate student-level introductory books in character theory and representation theory of finite groups.[11][12]
Isaacs is also the author of the book Algebra: A Graduate Course (first published in 1994; republished in 2009),[13] which received highly positive reviews.[14] Additionally, he is the author of Finite Group Theory (published in 2008).[15][16][17]
In 2009, a conference was held at the Universitat de Valencia in Spain to honor his contributions.[18] Following the conference, a festschrift was published by the American Mathematical Society.[19]
Isaacs was also a Fellow of the American Mathematical Society.[20]
Isaacs was a Pólya lecturer for the Mathematical Association of America. He received the Benjamin Smith Reynolds award for teaching engineering students at the University of Wisconsin and a UW Madison campus teaching award. He was also the recipient of a Sloan Foundation research award.
Isaacs died in February 2025.[5]