János Dezső Aczél (; 26 December 1924 – 1 January 2020), also known as John Aczel, was a Hungarian-

Canadian Canadians (french: Canadiens) are people identified with the country of Canada. This connection may be residential, legal, historical or cultural. For most Canadians, many (or all) of these connections exist and are collectively the source of ...

mathematician, who specialized in functional equations and

information theory Information theory is the scientific study of the quantification, storage, and communication of information. The field was originally established by the works of Harry Nyquist and Ralph Hartley, in the 1920s, and Claude Shannon in the 1940s. ...

Professional career

Aczél earned a doctorate in mathematical analysis from the

University of Budapest A university () is an institution of higher (or tertiary) education and research which awards academic degrees in several academic disciplines. ''University'' is derived from the Latin phrase ''universitas magistrorum et scholarium'', which ...

, and held positions at the

University of Cologne The University of Cologne (german: Universität zu Köln) is a university in Cologne, Germany. It was established in the year 1388 and is one of the most prestigious and research intensive universities in Germany. It was the sixth university to ...

, Kossuth University, University of Miskolc, and University of Szeged.Biography as a speaker at the Marschak Colloquium at UCLA
1999, accessed 25 January 2013. He joined the

University of Waterloo The University of Waterloo (UWaterloo, UW, or Waterloo) is a public research university with a main campus in Waterloo, Ontario, Canada. The main campus is on of land adjacent to "Uptown" Waterloo and Waterloo Park. The university also operates ...

faculty in 1965, eventually becoming Distinguished Professor in the Department of Pure Mathematics. He was the founder of the journal ''

Aequationes Mathematicae ''Aequationes Mathematicae'' is a mathematical journal. It is primarily devoted to functional equations, but also publishes papers in dynamical systems, combinatorics, and geometry. As well as publishing regular journal submissions on these topic ...

'', first published in 1968, and remained its honorary editor-in-chief.

Awards and honors

Aczél held honorary degrees from the

University of Karlsruhe The Karlsruhe Institute of Technology (KIT; german: Karlsruher Institut für Technologie) is a public research university in Karlsruhe, Germany. The institute is a national research center of the Helmholtz Association. KIT was created in 2009 ...

, the

University of Graz The University of Graz (german: link=no, Karl-Franzens-Universität Graz, ), located in Graz, Austria, is the largest and oldest university in Styria, as well as the second-largest and second-oldest university in Austria. History The univers ...

, and the

University of Silesia in Katowice The University of Silesia in Katowice ( pl, Uniwersytet Śląski w Katowicach, UŚ) is an autonomous state-run university in Silesia Province, Katowice, Poland. The university offers higher education and research facilities. It offers undergra ...

. In 1971, he was elected a fellow of the Royal Society of Canada. He was the 1988 winner of the Santiago Ramón y Cajal Medal. In 1990, he became an external member of the

Hungarian Academy of Sciences The Hungarian Academy of Sciences ( hu, Magyar Tudományos Akadémia, MTA) is the most important and prestigious learned society of Hungary. Its seat is at the bank of the Danube in Budapest, between Széchenyi rakpart and Akadémia utca. Its mai ...

,Member listing

, accessed 25 January 2013. and, in 2004, he was honored by the academy as one of the "big five" most distinguished Hungarian mathematicians. The other honorees were John Horvath,

Steven Gaal Steven Alexander Gaal (February 22, 1924 – March 17, 2016) (also known as István Sándor Gál or I. S. Gál) was a Hungarian- American mathematician and Professor of Mathematics at the University of Minnesota—Minneapolis. Education Ga ...

, Ákos Császár and László Fuchs.Tribute to the achievements of five outstanding Hungarian mathematicians
Department of Mathematical Sciences of the Hungarian Academy of Sciences In 2008, he became an honorary member of the

Hamburg Mathematical Society The Hamburg Mathematical Society (german: Mathematische Gesellschaft in Hamburg) is a learned society concerned with mathematics and located in the German city of Hamburg. It was founded in 1690 by Heinrich Meissner as the "Kunstrechnungsübende ...

, the oldest active mathematical society in the world. In 2004, he won the Kampé de Fériet Award of the annual Information Processing and Management of Uncertainty conference, "for his pioneering work on the theory of functional equations, with applications in many fields, such as information measures, index numbers, group decision making, aggregation, production functions, laws of science, theory of measurement and utility theory." Issues of the journal ''Aequationes Mathematicae'' were dedicated to Aczél in 1999, 2005, and 2010, in honor of his 75th, 80th, and 85th birthdays. He died six days after his 95th birthday on 1 January 2020..

Selected publications

Articles

* * * * *

Books

Aczél was the author or co-author of: *. *. Previously published in German as ''Vorlesungen über Funktionalgleichungen und ihre Anwendungen'' (Birkhäuser, 1961). *. *. *.Review of ''Functional equations in several variables'' by K. Lajkó, . He was the editor of: * (1st edition 1984) * (1st edition 1995)

References

External links

* Aczél'
homepage
at the Hungarian Academy of Sciences. *
Author profile
in the database

zbMATH zbMATH Open, formerly Zentralblatt MATH, is a major reviewing service providing reviews and abstracts for articles in pure and applied mathematics, produced by the Berlin office of FIZ Karlsruhe – Leibniz Institute for Information Infrastructur ...

{{DEFAULTSORT:Aczel, Janos 1924 births 2020 deaths 20th-century Hungarian mathematicians Canadian mathematicians Hungarian emigrants to Canada Naturalized citizens of Canada Members of the Hungarian Academy of Sciences University of Waterloo faculty Fellows of the Royal Society of Canada Mathematicians from Budapest