Knaster Bronisław

Bronisław Knaster - Personal data
Date of birth: 22nd May 1893
Place of birth: Warszawa
Date of death: 3rd November 1980
Place of death: Wrocław
Occupation: mathematician
Related towns: Warsaw, Wrocław

Knaster Bronisław (22 May 1893, Warsaw – 3 November 1980, Wrocław) – mathematician, representative of the Lwów School of Mathematics.

Bronisław Knaster's path to mathematics led through Warsaw, Paris, the army and… medicine. He arrived in Lwów late but is considered as one of the members of the Lwów School of Mathematics.

He was born in Warsaw on 22 May 1893, and like his father, a well-known physician, head of the Infant Jesus Clinical Hospital and president of the Association of Doctors, was to heal people. After graduating from high school, he went to France to study medicine at the Sorbonne. In 1914, he passed his first medical examinations, but after the outbreak of the Great War, he was sent to Warsaw and, after the establishment of a Polish university in 1915, he continued his studies there, but at the Faculty of Mathematics. “He believed that mathematics would be useful to him in his scientific work in the field of medicine (as a result he became absorbed by mathematics ...)” - Knaster's colleague from studies, Kazimierz Kuratowski recalled.

In 1923, he obtained his Ph.D. on the basis of thesis Un continu dont tout sous-continu est indecomposable, but by the time he took part in the Polish-Bolshevik war. He volunteered and served as a doctor. He was already married to Maria Morska, an actress, journalist for Wiadomości Literackie and one of the muses of poets from the Skamander group. Hence Knaster's acquaintance with Tuwim, Słonimski and Lechoń, which lasted until the end of the Second Polish Republic.

In 1925, he obtained his post-doctoral qualification and went to Italy for three years to treat malaria, which he contracted during the war. After his return, already as an assistant professor at the University of Warsaw, he conducted a seminar on topology, which became his main subject of interest; he was also the secretary of the Main Board of the Polish Mathematical Society. It was then that his closer contacts with Lwów mathematicians began. He came there to attend and give lectures, visited Scottish caffe, and competed with Steinhaus on mordacious remarks. He used to say, what his Ph.D. student Roman Duda remembered, that as a doctor he was primarily interested in the pathologies of the human body, and as a mathematician he was interested in “mathematical pathologies”, that is peculiar and unexpected sets.

He came to Lviv for good as late as in the autumn of 1939, after escaping from German-occupied Warsaw. At the Ivan Franko University, he received the desired professorship and a place in the Department of Geometry, headed by Stanisław Mazur. Several of his entries in the Scottish Book come from this period. After the Germans occupied Lviv, he and Banach were louse-feeders at the Weigl Institute. They constituted the so-called mathematical table where mathematical boundaries, elements of the theory of topology and space were debated during louse feeding. Linguistic puzzles were played as well. Knaster invented a contest for a sentence in which the same syllable would be repeated the largest number of times, without the sentence losing its meaning. He himself composed a seven-syllable sentence: Imama mama ma mamałygę. Nobody created a longer one.

After the war, he planned to stay in Krakow, he also exhorted Steinhaus to do so. He dissuaded him from the idea of going to the dangerous and still full of Germans Wrocław. "He advises me not to look for a tumor in Wrocław" –Steinhaus noted in his Wspomnienia i zapiski (Memories and Notes). In the end, however, it was Knaster who settled in Lower Silesia first and persuaded Steinhaus to come. Together with Edward Marczewski, they organised mathematics studies at the combined University and Polytechnic of Wrocław. He contributed to the reactivation of the Lwów Studia Mathematica yearbook and was also one of the founders of another magazine (nowadays published by the Polish Academy of Sciences) Colloquium Mathematicum.

They were provided with lodgings in the same former German villa: Knaster moved to the grand floor, Steinhaus to the upper floor of the house at Orłowskiego Street in Wrocław quarter of Biskupin. Until the end of their lives, they argued over the variation of the surname "Knaster", which amused the entire university. Bronisław Knaster believed that in the genitive it should be “Knastera", Steinhaus insisted that "Knastra".

- Forgive me, professor, but everyone is entitled to their own name – upset Knaster protested at one time.

- Yes, professor - he heard in reply - but only in the denominator.

Professors and students of mathematics joked that in the garden of the villa at Orłowskiego Street, in the Steinhaus’ part, astres grow, and in the Knaster’s part - aste

Bronisław Knaster died in Wrocław on 3 November 1980. 


Mathematical concepts related to the name of Bronisław Knaster:

- Knaster curve

- Knaster-Tarski theorem

- Knaster-Kuratowski fan

- Knaster-Kuratowski-Mazurkiew lemma


Read more about Lwów School of Mathematics

 Mariusz Urbanek


  • Marczewski E., O działalności B. Knastera, “Wiadomości Matematyczne”, no 11 form 1969.
  • Duda R.,Bronisław Knaster (1893-1980), “Wiadomości Matematyczne”, no 25 from 1983.
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