|Died||January 24, 1982 (aged 76)|
|Alma mater||Warsaw University|
|Known for||Borsuk's conjecture|
|Doctoral advisor||Stefan Mazurkiewicz|
Borsuk introduced the theory of absolute retracts (ARs) and absolute neighborhood retracts (ANRs), and the cohomotopy groups, later called Borsuk–Spanier cohomotopy groups. He also founded Shape theory. He has constructed various beautiful examples of topological spaces, e.g. an acyclic, 3-dimensional continuum which admits a fixed point free homeomorphism onto itself; also 2-dimensional, contractible polyhedra which have no free edge. His topological and geometric conjectures and themes stimulated research for more than half a century.
Borsuk received his master's degree and doctorate from Warsaw University in 1927 and 1930, respectively; his Ph.D. thesis advisor was Stefan Mazurkiewicz. He was a member of the Polish Academy of Sciences from 1952. Borsuk's students included Samuel Eilenberg, Jan Jaworowski, Krystyna Kuperberg, Włodzimierz Kuperberg, and Andrzej Trybulec.
- Geometria analityczna w n wymiarach (1950) (translated to English as Multidimensional Analytic Geometry, Polish Scientific Publishers, 1969)
- Podstawy geometrii (1955)
- Foundations of Geometry (1960) with Wanda Szmielew, North Holland publisher
- Theory of Retracts (1967), PWN, Warszawa.
- Theory of Shape (1975)
- Collected papers vol. I, (1983), PWN, Warszawa.
- Bing–Borsuk conjecture
- Borsuk's conjecture
- Borsuk–Ulam theorem
- Zygmunt Janiszewski
- Stanislaw Ulam
- Scottish Café
- Animal Husbandry, an educational dice game published by Borsuk at his own expense in 1943 during the German occupation of Warsaw.
- Freudenthal, H. (1961). "Review: Foundations of geometry, Euclidean and Bolyai–Lobachevskian geometry, projective geometry. By K. Borsuk and Wanda Szmielew. Revised English translation" (PDF). Bull. Amer. Math. Soc. 67 (4): 342–344. doi:10.1090/s0002-9904-1961-10606-x.
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