**Wolfgang Hahn** was a German mathematician who worked on special functions, in particular orthogonal polynomials.

- In his class were a number of Hohenzollern princes who, unlike Wolfgang, were not too bright.
- Hahn attended Schur's seminar and Remak also attended.
- However, Hahn said that Remak always seemed to be asleep in the seminar but, despite this, he would suddenly appear to wake up and ask a highly relevant question or explain a difficult point with which others were struggling.
- Hahn said that he had attended a lecture by Carl Ludwig Siegel but had not understood it at all.
- Hahn said that Edmund Landau always talked to his dog in Hebrew.
- Landau often organised quiz evenings to which Hahn was invited.
- After his year in Göttingen, Hahn returned to Berlin where he continued to undertake research advised by Schur.
- Since he was not Jewish, Hahn was not directly affected by this law but, nevertheless, it did have consequences for him.
- Hahn spent the years from 1933 to 1940 as a school teacher.
- During these years as a school teacher Hahn published some research articles: Bericht über die Nullstellen der Laguerreschen und Hermiteschen Polynome Ⓣ(Report on the zeros of Laguerre and Hermite polynomials) (1935); Über die Jacobischen Polynome und zwei verwandte Polynomklassen Ⓣ(On the Jacobi polynomials and two related polynomial classes) (1935); Über höhere Ableitungen von Orthogonalpolynomen Ⓣ(On higher derivatives of orthogonal polynomials) (1935); and Über Orthogonalpolynome mit drei Parametern Ⓣ(On orthogonal polynomials with three parameters) (1939).
- In 1940 Hahn was drafted into the Wehrmacht.
- Hahn remained in Germany until the war ended in 1945 and, following the victory by the Allies, he was prevented from returning to Germany until 1946.
- Hahn published three papers in 1949, namely: Über Orthogonalpolygnome, die q-Differenzengleichungen genügen Ⓣ(On orthogonal polygnomials satisfying q-difference equations); Über Orthogonalpolynome, die gleichzeitig zwei verschiedenen Orthogonalsystemen angehören Ⓣ(On orthogonal polynomials, simultaneously belonging to two different orthogonal systems); and Beiträge zur Theorie der Heineschen Reihen Ⓣ(Contributions to the theory of Heine ranks).
- In his habilitation thesis Hahn examined polynomials which today bear the name "Hahn polynomials", which already appears in the title of many works today.
- In 1952 Hahn was appointed as a Diätendozentur, a position that was newly created as a first step of an academic career, in the Department of Mathematics headed by Rudolf Iglisch (1903-1987) at the Technische Hochschule of Braunschweig.
- Professor Hahn liberally provided encouragement and offered assistance and advice to do just that.
- Although he had worked on Special Functions, orthogonal polynomials in particular, and lectured extensively on those subjects he became affectionately known as 'Stability Hahn' when his interest and his work in the field of stability of motions became apparent.
- We noted above that Hahn spent 1959-61 in Madras (now Chennai) in India.
- In 1962 Hahn left Braunschweig and went to the United States where he was well-known because of his book and he was invited to give lectures at many different universities.
- When Kreyszig left Graz in 1967 to take up a chair at the University of Düsseldorf, Hahn argued strongly for the appointment of Karl Wilhelm Bauer (born 1924) whom he had known from his time at Bonn.
- At Graz, Hahn built up a major research group in qqq-analysis.
- Hahn was strongly influenced by Eduard Heine.
- The Austrian School takes the development of q all the way from Jacob Bernoulli, Carl Gauss and Leonhard Euler in the 17th and 18th century, through the central European mathematicians of the nineteenth century: Eduard Heine, Johannes Thomae, Carl Jacobi, and from the twentieth century: Alfred Pringsheim, Ferdinand von Lindemann, Wolfgang Hahn, Peter Lesky (1926-2008) and Johann Cigler (1937-), the Englishman Frederick H Jackson, the Austrians Peter Paule, Josef Hofbauer, Alex Riese and the Frenchman Paul Appell.
- At the Technische Hochschule of Graz, Hahn was Dean of the faculty of Technology and Natural Sciences during 1967-69, Rector of the University during 1969-70, and Vice-Rector during 1970-72.
- In April 1981 Hahn reached 70 years of age and retired from his chair.
- The years immediately after he retired were sad ones for Hahn with his wife's health deteriorating rapidly.
- She died in 1983 and from that time Hahn lived alone in Graz.

Born 30 April 1911, Potsdam, Germany. Died 10 January 1998, Kassel, Germany.

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Origin Germany

**O’Connor, John J; Robertson, Edmund F**: MacTutor History of Mathematics Archive