Irving Kaplansky

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Irving Kaplansky
Irving Kaplansky2.jpg
Born March 22, 1917
Died June 25, 2006 (age 89)
Los Angeles
Nationality Canadian, American
Fields Mathematics
Institutions University of Chicago
Alma mater University of Toronto and Harvard University
Doctoral advisor Saunders Mac Lane
Doctoral students
Known for Kaplansky density theorem
Kaplansky conjecture
Group theory
Ring theory
Operator algebras
Game theory
field theory
Notable awards William Lowell Putnam Mathematical Competition (1938)
Guggenheim Fellowship (1948)
Jeffery–Williams Prize (1968)
Leroy P. Steele Prize (1989)

Irving Kaplansky (March 22, 1917 – June 25, 2006) was a mathematician, college professor, author, and musician.


Kaplansky (or "Kap," as his friends and colleagues called him) was born in Toronto, Ontario, Canada, to Polish-Jewish immigrants;[1][2] his father worked as a tailor, and his mother ran a grocery and, eventually, a chain of bakeries.[3][4][5] He attended the University of Toronto as an undergraduate. In his senior year, he competed in the first William Lowell Putnam Mathematical Competition, becoming one of the first five recipients of the Putnam Fellowship, which paid for graduate studies at Harvard University.[3] After receiving his Ph.D. from Harvard in 1941[6] as Saunders Mac Lane's first student, he remained at Harvard as a Benjamin Pierce Instructor, and in 1944 moved with Mac Lane to Columbia University for a year where he worked on the Manhattan Project, collaborating with many of the brilliant minds in mathematics like John von Neumann. He was professor of mathematics at the University of Chicago from 1945 to 1984, and Chair of the department from 1962 to 1967. Kaplansky was the Director of the Mathematical Sciences Research Institute from 1984 to 1992, and the President of the American Mathematical Society from 1985 to 1986.

Kaplansky was also an accomplished amateur musician. He had perfect pitch, studied piano until the age of 15, earned money in high school as a dance band musician, taught Tom Lehrer, and played in Harvard's jazz band in graduate school. He also had a regular program on Harvard's student radio station. After moving to the University of Chicago, he stopped playing for two decades, but then returned to music as an accompanist for student-run Gilbert and Sullivan productions and as a calliope player in football game parades.[3] He often composed music based on mathematical themes. One of those compositions, A Song About Pi, is a melody based on assigning notes to the first 14 decimal places of pi, and has occasionally been performed by his daughter, singer-songwriter Lucy Kaplansky.

Mathematical contributions[edit]

Kaplansky made major contributions to group theory, ring theory, the theory of operator algebras, field theory and created the Kaplansky density theorem and Kaplansky conjecture. He published more than 150 articles and over 20 mathematical books.

Kaplansky was the doctoral supervisor of 55 students including notable mathematicians Hyman Bass, Susanna S. Epp, Günter Lumer, Eben Matlis, Donald Ornstein, Ed Posner, Alex F. T. W. Rosenberg, Judith D. Sally, and Harold Widom. He has over 800 academic descendants, including many through his academic grandchildren David J. Foulis (who studied with Kaplansky at the University of Chicago before completing his doctorate under the supervision of Kaplansky's student Fred Wright, Jr.) and Carl Pearcy (the student of H. Arlen Brown, who had been jointly supervised by Kaplansky and Paul Halmos).[6]

Awards and honors[edit]

Kaplansky was a member of the National Academy of Sciences and the American Academy of Arts and Sciences, Director of the Mathematical Sciences Research Institute, and President of the American Mathematical Society. He won the William Lowell Putnam Mathematical Competition, the Guggenheim Fellowship, the Jeffery-Williams Prize, and the Leroy P. Steele Prize.

Selected publications[edit]


  • Kaplansky, Irving (1954). Infinite Abelian groups. [7] revised edn. 1971 with several later reprintings
  • —— (1955). An introduction to differential algebra. University of Chicago Press.  2nd edn. Paris: Hermann. 1957. 
  • —— (1966). Introdução à teoria de Galois, por I. Kaplansky. Pref. de Elon Lages Lima. 
  • —— (1968). Rings of operators. 
  • —— (1969). Fields and rings.  2nd edn. 1972
  • —— (1969). Linear algebra and geometry; a second course.  revised edn. 1974
  • —— (1970). Algebraic and analytic aspects of operator algebras. 
  • —— (1971). Lie Algebras and Locally Compact Groups. University of Chicago Press. ISBN 0-226-42453-7.  several later reprintings
  • —— (1972). Set theory and metric spaces.  2nd edn. 1977
  • —— (September 1974). Commutative Rings. Lectures in Mathematics. University of Chicago Press. ISBN 0-226-42454-5.  1st edn. 1966; revised 1974 with several later reprintings

with I. N. Herstein: —— (1974). Matters mathematical.  2nd edn. 1978


See also[edit]


  1. ^ Irving Kaplansky Memoir by Nancy E. Albert
  2. ^ Making Family Stories into Art
  3. ^ a b c Albers, Donald J.; Alexanderson, Gerald L.; Reid, Constance, eds. (1990), "Irving Kaplansky", More Mathematical People, Harcourt Brace Jovanovich, pp. 118–136 .
  4. ^ Irving Kaplansky — mathematician and author
  5. ^ In memoriam: Irving Kaplansky
  6. ^ a b Irving Kaplansky at the Mathematics Genealogy Project
  7. ^ Baer, Reinhold (1955). "Review: Infinite abelian groups by I. Kaplansky" (PDF). Bull. Amer. Math. Soc. 61 (1): 88–89. doi:10.1090/s0002-9904-1955-09877-x. 


External links[edit]