Stefan Banach

Born on 30 March 1892 in Krakow, Austria-Hungary (now Poland), Stefan Banach is considered one of the most important and influential mathematicians of the 20th century. Banach started off in engineering, studying at Lvov Technical University from 1910 to 1914. Because of poor vision in his left eye, he was deemed unfit for military service and instead spent World War I building roads and teaching in local schools. A chance meeting with fellow Pole and mathematician Hugo Steinhaus led to the publication of Banach’s first mathematical paper in 1918. He went on to earn his doctorate at Lvov in 1922 and was made a full professor in 1924. Banach’s most important contribution to mathematics was the development of a systematic theory of functional analysis, which involves the study of vector spaces, including the eponymous Banach spaces. Many other theorems and concepts also bear his name, including Banach algebras, the Banach–Steinhaus theorem, and the Banach–Tarski paradox. Besides continuing to produce important scientific papers, Banach wrote arithmetic, geometry, and algebra texts for high schools and, together with Steinhaus, started a new journal, Studia Mathematica. In 1939 Banach was elected president of the Polish Mathematical Society. He was forced to leave academia, however, during the Nazi occupation from 1941 to 1944. Banach died in Lvov of lung cancer in 1945. (Photo credit: Hussein abdulhakim, CC BY-SA 3.0 )

Date in History: 30 March 1892