Emeritus Professor Louis Solomon passed away Wednesday, November 18, at his home. He attended Harvard for his undergraduate education, and after two years of service in the Army, returned for graduate study, receiving his PhD from Harvard in 1958 under Professor Richard Brauer. Following positions at the Rockefeller Institute, Haverford College, and New Mexico State University, two summers at Los Alamos National Laboratory, and a year as a visiting scholar at the Institute for Advanced Study, he joined the Mathematics Department at the University of Wisconsin-Madison in 1969 and retired in 2000. A week-long meeting "Combinatorics of Lie Type,” hosted by the University of Wisconsin Mathematics Department in June 2000, drew 130 participants from all over the world to celebrate his career, mathematics, retirement, and birthday.

Lou made many important contributions to the study of reflection groups and Coxeter groups. Solomon's descent algebra is a mainstay of the theory. His series of influential papers in the 1980s with Peter Orlik, and later together with Hiroaki Terao, pioneered the study of hyperplane arrangements. The Orlik-Solomon algebra that resulted from these papers is closely related to the shuffle algebra used by Diaconis and others in the study of card shuffling. Lou was named a Fellow of the American Mathematical Society in the inaugural class of 2013.

He is survived by his wife of 60 years Elsbeth Aellig Solomon, son Jeremy Solomon, daughter Susan Solomon, and three grandchildren.