Ellis Kolchin

Ellis Robert Kolchin was an American mathematician at Columbia University, born on 18 April 1916 and died on 30 October 1991. He is best known for his work in differential algebra and especially differential Galois theory. He earned his doctorate in mathematics at Columbia in 1941 under the supervision of Joseph Ritt, served in the South Pacific in the Second World War and held Guggenheim Fellowships in 1954 and 1961. He worked on differential algebra and its relation to differential equations, and founded the modern theory of linear algebraic groups, developing basic theorems such as an analogue of the Hilbert Basis Theorem. His book Differential Algebra and Algebraic Groups became very influential. He gave a plenary address at the 1966 International Congress of Mathematicians in Moscow, outlining what are now called Kolchin's problems, and ran the Kolchin Seminar at Columbia, which went on for more than thirty years.