Semyon Aranovich Gershgorin

Semyon Aranovich Gershgorin was a Belarusian mathematician, born in Pruzhany on 24 August 1901, who produced important results in numerical approximation. His family name is transliterated in several ways, including Gerschgorin, and is originally Yiddish. He studied at the Petrograd Technological Institute from 1923, defending a thesis in mechanics, and became professor at the Institute of Mechanical Engineering in Leningrad in 1930. His most famous paper, published in 1931 under the title Über die Abgrenzung der Eigenwerte einer Matrix, gave powerful estimates for the eigenvalues of a matrix, known as his Circle Theorem. He died in Leningrad on 30 May 1933.