**Cornelius Lanczos** was born Kornél Löwy but when there was a reaction in Hungary against German names he, along with large numbers of his countrymen, changed his name from the German form and became Kornél Lánczos (or rather, Lánczos Kornél since Hungarians put the family name first). His family were of Jewish origins, his father being a lawyer. Lanczos attended a Jewish elementary school where he learn several foreign languages, then he entered the local Gymnasium which was a Catholic school run by the Cistercians.

He graduated from the gymnasium in 1910 and, the following September, he entered the University of Budapest. There he had several inspiring teachers who were to make a great impression on Lanczos. His physics teacher was Eötvös who first interested Lanczos in relativity. His mathematics teacher was Fejér and Lax writes in [2]:-

Lanczos was much influenced by Fejér; he learnt from him about Fourier series, orthogonal polynomials, and interpolation. It is likely that Lanczos was influenced by Fejér's style of lecturing...

After graduating in 1915, Lanczos was appointed an assistant at the Technical University of Budapest. He worked on relativity theory and after writing his dissertation *Relation of Maxwell's Aether Equations to Functional Theory* he sent a copy to Einstein. It impressed Einstein who replied:-

I have read your work in as much detail as my present excess of work allows. I can say that it is sound and original thinking. It makes you worthy of the doctorate. I am pleased to give you my permission to honour me by dedicating it to me.

Lanczos received his doctorate in 1921 and, because of laws in Hungary against Jews, he went to Germany taking up a post at the University of Freiburg. He spent three years in Freiburg, then took up a post in Frankfurt am Main where he became a colleague of Paul Epstein. During the year 1928-29 Lanczos was Einstein's assistant in Berlin, returning to Frankfurt in 1929.

In 1931 Lanczos spent a year as a visiting professor at Purdue University in West Lafayette, Indiana. Returning to Germany he found that the political situation there becoming unacceptable for someone of Jewish origin and he returned to a Professorship at Purdue in 1932. As Gellai writes in [3]:-

Had he not been compelled to leave Germany for the United States, the field of applied mathematics might lack today several very useful and elegant mathematical methods.

During his time at Purdue, Lanczos published mathematical physics papers at first but in 1938 he published his first work in numerical analysis. Two years later he published a matrix method of calculating Fourier coefficients which, over 25 years later, was recognised as the 'Fast Fourier Transform' algorithm described by Tukey. Lanczos continued to work on his first love of relativity and corresponded with Einstein both on a scientific level and as a friend. A new young man was appointed as Head of Physics at Purdue and Lanczos felt his work there was no longer appreciated. He wrote to Einstein:-

This brings me into a most difficult situation and I am trying desperately to get away from here.

Lanczos spent the year of 1944 working for the Boeing Aircraft Company and, in 1946, he resigned his post in Purdue to take up a permanent appointment with Boeing. There he worked on applications of mathematics to aircraft design and was able to develop new numerical methods to solve the problems.

In 1949 he moved to the Institute for Numerical Analysis of the National Bureau of Standards in Los Angeles. Here he worked on developing digital computers and was able to produce versions of the numerical methods he had developed earlier to program on the digital computers. At the Institute for Numerical Analysis he had Otto Szász, Taussky-Todd and her husband John Todd as colleagues.

However during the early 1950s United States senator Joseph R McCarthy whipped up strong feelings against communism in the USA. At the Institute for Numerical Analysis, as in many other institutions, there were investigations and suspicions and the atmosphere became unpleasant. Lanczos was therefore delighted to receive an offer from Schrödinger to head the Theoretical Physics Department at the Dublin Institute for Advance Study in Ireland. He took up the post in 1952 and, as Gellai writes in [3]:-

A very special, and in some ways the most beautiful, period of his life started there when he returned again to his 'first love' in science, devoting himself primarily to the study of the theory of relativity. Indeed, this position offered the support and the circumstances which he had longed for his entire life.

Lanczos published over 120 papers and books in a career spanning over 40 years. About half of these papers and books were published after he took up the position in Dublin. He certainly travelled widely during this period, most often in the United states. While on a visit to the Eötvös Lóránd University in Budapest in 1974 he had a sudden heart attack and died in hospital the following day.

**Article by:** *J J O'Connor* and *E F Robertson*

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