Professor Emeritus of Mathematics Irving Segal died while walking near his home in Lexington on Aug. 30. He was 79 years old.
Segal served on the MITfaculty for 38 years. During his time at the Institute, he helped to upgrade and improve the undergraduate curriculum in math.
Segal was born in the Bronx on Sept. 13, 1918. He grew up in Trenton, N.J. As an undergraduate, he attended Princeton University and received his bachelor's degree in mathematics in 1937. Segal went on to receive his doctorate in mathematics from Yale University in 1940. In 1941, Segal was an instructor at harvard University and from 1941 through 1943, Segal returned to Princeton as a research associate. Segal went on to serve the US Army conducting ballistics research at the Aberdeen Proving Grounds. He then worked in at the Institute for Advanced Study from 1945 to 1948. He then joined the faculty at the University of Chicago, where he eventually became a full professor. In 1960, Segal joined the MITfaculty and became professor emeritus in 1989.
In his early work, Segal studied the applications of algebraic methods to fundamental physics. In 1947, he spurred a great deal of active research by publishing a system of postulates for general quantum mechanics.
Later in his career, Segal used his chronometric theory and applied it to studies in astrophysics, which led to a parameter-free theory of the red-shift and an alternative model of the universe.
Segal also generalized much of Norbert Wiener's work in stochastic integration and the foundations of noncommutative geometry.
Professor Segal was a member of the American Astronomical, Mathematical, and Physical Societies. He was elected to the American Academy of Arts and Sciences, the Royal Danish Academy of Sciences, and the National Academy of Sciences. Segal was also a John Simon Guggenheim fellow in 1947, 1951, and 1967. He received the Alexander von Humboldt Award in 1981. He was also founder and managing editor of the Journal of Functional Analysis. In his career, he wrote three books and authored over 200 papers.
Segal was a visiting professor at several universities worldwide including Columbia University, La Sorbonne, Lund University, University of Pisa, Aarhus University, College de France, Institute of Mathematics and Theoretical Physics, Copenhagen and the University of Moscow.
Segal also was a committed adviser to graduate students. He was adviser to Professors of Mathematics Emeriti Isadore Singer and Bertram Kostant and Edward Nelson, now a professor at Princeton.
Professor Segal is survived by his wife Dr. Martha Segal of Lexington; their six-year-old daughter daughter, Miriam, of Lexington; three children from an earlier marriage, William of Bethesda, Md., Andrew of Espinola, N.M., and Karen of New York City; and four grandchildren. His first wife, Osa MacLane of Chicago, mother of William, Andrew and Karen, also survives.