Zygmunt Zahorski's works on the first derivative

Władysław Wilczyński

Antiquitates Mathematicae, Tome 7 (2013), pp. 247-252.

Résumé

Zygmunt Zahorski was born in 1914. In 1932 he began his studies at the Faculty of Mechanics, the Warsaw Polytechnic intending to study aeronautical engineering. Two years later he joined to the Faculty of Mathematics at Warsaw University for parallel study (in slow motion) where he included two full years and, in the same time, a part of the third year course at the Polytechnic. The mathematical studies he completed in 1939. He published his first work in 1937. In the same year he started working as an assistant in the Aviation Cadet School in Warsaw. At the same time preparing his doctoral thesis under the supervision of prof. Stefan Mazurkiewicz. Defense was planned for September 1939. The World War II thwarted these plans.Zygmunt Zahorski went to Lviv, where he was an assistant at the Chair of Stefan Banach. It was a period of intense scientific work. After the occupation of Lviv by the Germans Zygmunt Zahorski returned to Warsaw and managed to take a job at the Philips factory. This produced a new scientific results and although some manuscripts have been lost in the Warsaw Uprising, but after the war they have been recovered in large part. Zygmunt Zahorski scientific work did not stop even when he was staying at the Hospital of the Infant Jesus at Nowgorodzka Street. After the war, the Jagiellonian University hired him as an assistant. Zahorski’s mathematical achievements during the war was so significant that in 1946 he obtained a doctorate (promoter was Tadeusz Ważewski), and in 1947, he became assistant professor at the Jagiellonian University. A year later, he received a nomination for associate professor and moved to the University of Lodz. Council of the Faculty of Mathematics, Physics and Chemistry, University of Lodz intended to ask for him the title of professor in 1954, but Zygmunt Zahorski, critically assessing his achievements to date, found only in 1960 (after proving the so called Kolmogorov theorem on permutation of trigonometric series) that significantly this title deserves. In 1970 he moved to the Silesian Technical University in Gliwice. He worked there until his retirement. He died in 1998.

Détail

DOI : 10.14708/am.v7i0.583

Classification : 60K25, 90B22.
Mots-clés : history of mathematics, history of science, calculus

Bibliographie

Cytowane prace Zygmunta Zahorskiego

[Zl] Über die Konstruktion der differenzierbaren, monotone, nicht konstanten Funktion, mit überall dichter Menge von Konstantzintervallen, Sprawozdania Towarzystwa Naukowego Warszawskiego XXX, 1937, Wydział III, 202-206.

[Z2] O zbiorze punktów nieróżniczkowalności funkcji ciągłej (w jęz. rosyjskim), Mat. Sbornik t. 9 (51):3, 1941, 487-510.

[Z3] Über die Menge der Punkte in welchen die Ableitung unendlich ist, Tohoku Math. Journal 48 (2), 1941, 321-330.

[Z4] Sur la première dérivée, Transactions of the American Mathematical Society, Vol. 69, No 1, 1-54, July 1950.

[Z5] Sur la courbes dont la tangente prend sur tout arc partiel toutes les directions, Czechoslov. Math. Journal, t. 1 (76), 1952, 105-117.

Cytowane prace innych autorów

[BI] A. M. Bruckner, A theorem on monotonicity and a solution to a problem of Zahorski, Bull. Amer. Math. Soc. 71 (1965), 713-716.

[B2] A. M. Bruckner, An affirmative answer to a problem of Zahorski and some sequences, Mich. Math. J. 13 (1966), 15-26.

[B3] A. M. Bruckner, Creating differentiability and destroying derivatives, Amer. Math. Monthly 85, 7 (1978), 554-562.

[B4] A. M. Bruckner, Differentiation of Real Functions, Lecture Notes in Math. 659, Springer-Verlag 1978.

[Br] A. Brudno, Ciągłość a różniczkowalność (w jęz. rosyjskim), Mat. Sbornik 13 (55), 1943, 119-144.

[HS] E. Hewitt, K. Stromberg, Real and abstract analysis, Springer-Verlag 1969.

[L] J. Lipiński, Une propriété des ensembles {f'(x) > a}, Fund. Math. 42 (1955), 339-342.

[ŁW] E. Łazarow, W. Wilczyński, I-approximate derivatives, Radovi Mathematički, Vol. 5 (1989), 15-27.

[P] D. Preiss, Level sets of derivatives, Transactions of the American Mathematical Society 272 (1982), 161-184.

[Ś] T. Świątkowski, On the condition of monotonicity of functions, Fund. Math. 59 (1966), 189-201.

[T] G. Tolstoff, Sur quelques propriétés des fonctions approximativement continues, Rec. Mat. (Mat. Sbornik), N.S. 5 (1939), 637-645.