Joseph Ritt

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Joseph Fels Ritt (born August 23, 1893 in New York City , † January 5, 1951 ) was an American mathematician.

Ritt studied from 1908 at the City College of New York , where he won several mathematics prizes. Since he had to earn money, he worked from 1910 at the Naval Observatory in Washington, DC , but continued to study at the same time at George Washington University (bachelor's degree in 1913). He then continued his studies with a scholarship at Columbia University , where he received his doctorate in 1917 under Edward Kasner and he then worked as a computer for the government during the First World War. In 1921 he was there Assistant Professor, 1927 Associate Professor and 1931 Professor at Columbia University, from 1945 as Davies Professor of Mathematics . From 1942 to 1945 he was head of the mathematics faculty.

Independently of Fatou and Julia , Ritt obtained many of their results via the iteration of rational functions. Another important theorem of his concerns the uniqueness of the factorization of polynomials under composition. The largest and most important part of his work concerns the algebraic theory of differential equations , about which he also wrote two books ( Differential equations from an algebraic standpoint and Differential Algebra ). In 1948 his book Integration in Finite Terms appeared on the integration of elementary functions (following Joseph Liouville ). The search for general algorithms turned out to be a relatively difficult problem and was only solved in 1968 by Robert Risch . Later Ritt also dealt with the application of Lie groups in the theory of differential equations.

In 1950 he gave a plenary lecture at the International Congress of Mathematicians (ICM) in Cambridge (Massachusetts) ( Differential Groups ). In 1932 he was Colloquium Lecturer of the American Mathematical Society , of which he was Vice President from 1938 to 1940. He was a member of the National Academy of Sciences since 1933 .

Ellis Kolchin is one of his doctoral students .

In his honor, the Faculty of Mathematics at Columbia University has been offering post-graduate students temporary positions as "Joseph F. Ritt Assistant Professor " or Instructor since 1960 .

Fonts

  • Differential equations from an algebraic standpoint, New York, American Mathematical Society 1932
  • Theory of Functions, New York 1945, 1947
  • Integration in finite terms: Liouville's Theory of Elementary Methods, Columbia University Press 1948
  • Differential Algebra, American Mathematical Society 1950, Dover 1966

Web links

Individual evidence

  1. ^ JF Ritt, On the iteration of rational functions. Transactions of the American Mathematical Society, Vol. 21, pp. 348-356, 1920
  2. ^ JF Ritt, Prime and composite polynomials, Transactions of the American Mathematical Society, Volume 23, pp. 51-66, 1922.
  3. ^ Martin B. Margulies: Math Department Has Few Tenure Losses. In: Columbia Daily Spectator. , Volume CIV, Number 83, March 7, 1960, p. 1.
personal data
SURNAME Ride, Joseph
ALTERNATIVE NAMES Ritt, Joseph Fels (full name)
BRIEF DESCRIPTION American mathematician
DATE OF BIRTH August 23, 1893
PLACE OF BIRTH New York City
DATE OF DEATH 5th January 1951
Place of death New York City