Semyon Aranovich Gershgorin studied at Petrograd Technological Institute from 1923, becoming Professor in 1930, and from 1930 he worked in the Leningrad Mechanical Engineering Institute on algebra, theory of functions of complex variables, numerical methods and differential equations.
His 1931 paper Über die Abgrenzung der Eigenwerte einer Matrix ('About the limits of Eigenvalues in a Matrix', his only one not in Russian) gave powerful estimates for matrix eigenvalues, known as his Circle Theorem.
Article by: Chris McGhee
October 2004