**Stanisław Saks** was a Polish mathematician who worked in topology, set theory and functional analysis. He was one of the frequenters of the *Scottish Café*.

- Saks completed his studies at this school and received his high school diploma in 1915.
- Saks entered the newly refounded university on this occasion of great rejoicing for all patriotic Poles.
- In addition to Dickstein, two of Saks' first teachers at the University of Warsaw were Zygmunt Janiszewski and Stefan Mazurkiewicz who both began teaching there when the university reopened in November 1915.
- Saks was one of the founders of the Union.
- Saks became an editor of its paper "Independent Voice".
- Saks took a break from his studies in 1919-21 serving in the Polish Army and participating in a plebiscite campaign in Upper Silesia which yielded mixed results.
- In 1921 Saks' first mathematics paper, Sur l'équivalence de deux théorèmes de la théorie des ensembles Ⓣ(On the equivalence of two theorems of set theory), was published in the second volume of Fundamenta Mathematicae.
- Saks continued to study mathematics for his doctorate, returning to the University of Warsaw on 21 November 1921.
- Certainly, therefore, it was an exciting period during which Saks embarked on a research career and he was awarded his doctorate on 26 October 1922, Cum Laude Maxima, for the thesis A contribution to the theory of surfaces and plane domains.
- Saks' second paper was written in collaboration with Aleksander Rajchman (1890-1940).
- The Saks-Rajchman joint paper was Sur la dérivabilité des fonctions monotones Ⓣ(On the derivability of monotonic functions) (1923).
- In 1924 Saks published a number of papers: Sur les nombres dérivés des fonctions Ⓣ(On numbers derived from functions); Sur un théorème de M Lusin Ⓣ(On a theorem of M.
- Even before the doctorate was awarded, Saks began teaching at Warsaw Technical University and from 1926 he also lectured at the University of Warsaw after he habilitated there on 22 October 1926.
- Stanislaw Saks helped edit the paper and later deepened the result by introducing in its proof the notion of category.
- Stanislaw and Zofia Saks had one son, Marek Saks.
- This gave birth to a class of spaces that are still actively studied and that are now called spaces with the Banach-Saks property.
- Saks continued to teach at both Warsaw institutions until 1939.
- Antoni Zygmund had become a colleague and friend of Saks early in his career.
- He was appointed to Warsaw Technical University shortly after Saks began to lecture there, and the two began to collaborate on mathematical projects.
- One of the works for which Saks is most famous is their joint book Analytic functions which appeared in 1938 as volume eight in the Mathematical Monographs series.
- This was not Saks' first monograph, however, for he had already published an important volume in the Mathematical Monographs series.
- This monograph was based on lecture courses Saks had given at the University of Warsaw.
- We have already mentioned Mazurkiewicz, Sierpinski, and Zygmund as major influences on Saks.
- Three times Saks was put forward as a candidate for a mathematics chair.
- The application to the Faculty Council of Mathematics and Natural Sciences of the University of Warsaw in 1936 ran into difficulties due to the growing anti-Semitism and, to avoid further unpleasantness, Saks withdrew the application himself.
- When war broke out in 1939 Saks joined the Polish army and retreated with them to Lwów which was by that time under Russian control.
- In Lwów, Saks joined the community of mathematicians working and drinking in the Scottish Café.
- They made Banach Dean of the Division of Mathematics and Natural Sciences, and thanks to his belief that cooperation was optimal in our situation, he managed to get Saks and Knaster appointed professors - not an easy thing to do since the Soviets seemed to have an innate dislike of people from Warsaw.
- Saks returned to Warsaw where he was arrested, put in prison and killed by the Gestapo (allegedly while attempting to escape from prison).
- In November 1942, at the age of 45, Saks died in a Warsaw prison, victim of a policy of extermination.

Born 30 December 1897, Kalisz, Russian Empire (now Poland). Died 23 November 1942, Warsaw, Poland.

View full biography at MacTutor

Origin Poland

**O’Connor, John J; Robertson, Edmund F**: MacTutor History of Mathematics Archive