Karol Borsuk

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Karol Borsuk (May 8, 1905, Warsaw - January 24, 1982, Warsaw) was a Polish mathematician. His main interest was topology.

Borsuk introduced the theory of absolute retracts (ARs) and absolute neighborhood retracts (ANRs), and the cohomotopy groups, later called Borsuk-Spanier cohomotopy groups. 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. He was a member of the Polish Academy of Sciences since 1952. Borsuk's students included Samuel Eilenberg and Krystyna Kuperberg.

[edit] See also

• Borsuk's conjecture
• Borsuk-Ulam theorem
• Zygmunt Janiszewski
• Stanislaw Ulam

[edit] Works

• Geometria analityczna w n wymiarach (1950)
• Podstawy geometrii (1955)
• Theory of Retracts (1966)
• Theory of Shape (1975)

[edit] External links

• O'Connor, John J., and Edmund F. Robertson. "Karol Borsuk". MacTutor History of Mathematics archive.
• Karol Borsuk at the Mathematics Genealogy Project