Stefan Cohn-Vossen (28 May 1902 – 25 June 1936) was a

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, mathematical structure, structure, space, Mathematica ...

, who was responsible for Cohn-Vossen's inequality and the Cohn-Vossen transformation is also named after him. He proved the first version of the

splitting theorem In the mathematical field of differential geometry, there are various splitting theorems on when a pseudo-Riemannian manifold can be given as a metric product. The best-known is the Cheeger–Gromoll splitting theorem for Riemannian manifolds, alth ...

. He was also known for his collaboration with

David Hilbert David Hilbert (; ; 23 January 1862 – 14 February 1943) was a German mathematician and philosopher of mathematics and one of the most influential mathematicians of his time. Hilbert discovered and developed a broad range of fundamental idea ...

on the 1932 book ''Anschauliche Geometrie'', translated into

English English usually refers to: * English language * English people English may also refer to: Culture, language and peoples * ''English'', an adjective for something of, from, or related to England * ''English'', an Amish ter ...

as ''

Geometry and the Imagination ''Geometry and the Imagination'' is the English translation of the 1932 book by David Hilbert and Stefan Cohn-Vossen. The book was based on a series of lectures Hilbert made in the winter of 1920–21. The book is an attempt to present some ...

''. He was born in Breslau (then a city in the

Kingdom of Prussia The Kingdom of Prussia (, ) was a German state that existed from 1701 to 1918.Marriott, J. A. R., and Charles Grant Robertson. ''The Evolution of Prussia, the Making of an Empire''. Rev. ed. Oxford: Clarendon Press, 1946. It played a signif ...

; now

Wrocław Wrocław is a city in southwestern Poland, and the capital of the Lower Silesian Voivodeship. It is the largest city and historical capital of the region of Silesia. It lies on the banks of the Oder River in the Silesian Lowlands of Central Eu ...

Poland Poland, officially the Republic of Poland, is a country in Central Europe. It extends from the Baltic Sea in the north to the Sudetes and Carpathian Mountains in the south, bordered by Lithuania and Russia to the northeast, Belarus and Ukrai ...

). He wrote a 1924 doctoral dissertation at the

University of Breslau A university () is an educational institution, institution of tertiary education and research which awards academic degrees in several Discipline (academia), academic disciplines. ''University'' is derived from the Latin phrase , which roughly ...

(now the

University of Wrocław The University of Wrocław (, UWr; ) is a public research university in Wrocław, Poland. It is the largest institution of higher learning in the Lower Silesian Voivodeship, with over 100,000 graduates since 1945, including some 1,900 researcher ...

) under the supervision of

Adolf Kneser Adolf Kneser (19 March 1862 – 24 January 1930) was a German mathematician. He was born in Grüssow, Grand Duchy of Mecklenburg-Schwerin and died in Breslau, Germany. He is the father of the mathematician Hellmuth Kneser and the grandfather of ...

. He became a professor at the

University of Cologne The University of Cologne () is a university in Cologne, Germany. It was established in 1388. It closed in 1798 before being re-established in 1919. It is now one of the largest universities in Germany with around 45,187 students. The Universit ...

in 1930. He was barred from lecturing in 1933 under Nazi racial legislation, because he was

Jew Jews (, , ), or the Jewish people, are an ethnoreligious group and nation, originating from the Israelites of ancient Israel and Judah. They also traditionally adhere to Judaism. Jewish ethnicity, religion, and community are highly inte ...

ish.. In 1934 he emigrated to the

USSR The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

, with some help from

Herman Müntz 250px (Chaim) Herman Müntz (28 August 1884, in Łódź – 17 April 1956, in Sweden) was a German mathematician, now remembered for the Müntz approximation theorem. Biography He was born in Łódź (then in the Piotrków Governorate of th ...

. While there, he taught at

Leningrad University Saint Petersburg State University (SPBGU; ) is a public university, public research university in Saint Petersburg, Russia, and one of the oldest and most prestigious universities in Russia. Founded in 1724 by a decree of Peter the Great, the uni ...

. He died in

Moscow Moscow is the Capital city, capital and List of cities and towns in Russia by population, largest city of Russia, standing on the Moskva (river), Moskva River in Central Russia. It has a population estimated at over 13 million residents with ...

from

pneumonia Pneumonia is an Inflammation, inflammatory condition of the lung primarily affecting the small air sacs known as Pulmonary alveolus, alveoli. Symptoms typically include some combination of Cough#Classification, productive or dry cough, ches ...

.Cohn-Vossen's Obituary
(in

Russian Russian(s) may refer to: *Russians (), an ethnic group of the East Slavic peoples, primarily living in Russia and neighboring countries *A citizen of Russia *Russian language, the most widely spoken of the Slavic languages *''The Russians'', a b ...

)

References

External links

Anschauliche Geometrie
at

Göttinger Digitalisierungszentrum The Center for Retrospective Digitization in Göttingen () is an online system for archiving academic journals maintained by the University of Göttingen. See also *JSTOR JSTOR ( ; short for ''Journal Storage'') is a digital library of aca ...

Cohn-Vossen transformation
at

Encyclopedia of Mathematics The ''Encyclopedia of Mathematics'' (also ''EOM'' and formerly ''Encyclopaedia of Mathematics'') is a large reference work in mathematics. Overview The 2002 version contains more than 8,000 entries covering most areas of mathematics at a graduat ...

1902 births 1936 deaths 20th-century German mathematicians Differential geometers Jewish refugees from Nazi Germany in the Soviet Union Scientists from the Province of Silesia Soviet mathematicians University of Breslau alumni Academic staff of the University of Cologne Deaths from pneumonia in the Soviet Union {{germany-mathematician-stub