Stefan Banach

Stefan Banach (born March 30 1892 in Kraków, Poland - August 31 1945), a Polish mathematician, one of the moving spirits of the Lvov school of mathematics in pre-war Poland. He was largely self-taught in mathematics; his genius was accidentally discovered by Hugo Steinhaus. When World War II began, Banach was President of the Polish Mathematical Society and a full professor of Lvov University. Being a corresponding member of Academy of Sciences of the Ukrainian SSR, and otherwise on good terms with Soviet mathematicians, he was allowed to keep his chair despite the Soviet occupation, from 1939, of Lvov. Banach survived the subsequent brutal German occupation from 1941, earning a living by feeding lice on his blood in typhoid fever research conducted under Prof. Rudolf Weigl. His health declined during the occupation, and he developed lung cancer. Lvov was incorporated into the Soviet Union after the war, and Banach died there before he could be repatriated to Poland .

Théorie des opérations linéaires (Teoria operacji liniowych, 1932) is regarded as Banach's most influential work. He also initiated and edited the Studia Mathematica series.

Stanislaw Marcin Ulam, another mathematician of the Lvov school of mathematics, in his autobiography, attributes this to Banach: "Good mathematicians see analogies. Great mathematicians see analogies between analogies".

Banach was the founder of functional analysis; he also made important contributions to the theory of vector spaces, measure theory, set theory and other branches of mathematics.