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Adolf Abraham Halevi Fraenkel

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17 Feb 1891

Munich, Germany

15 Oct 1965

Jerusalem, Israel

Abraham Fraenkel, in common with most students in Germany in his time, studied for periods at different universities. He spent some time at the University of Munich, the University of Marburg, the University of Berlin and the University of Breslau. From 1916 he lectured at the University of Marburg, being promoted to professor there in 1922.

In 1928 Fraenkel left Marburg and spent one year teaching at the University of Kiel. He was a fervent Zionist and, after leaving Kiel, he taught at the Hebrew University of Jerusalem from 1929, joining the university four years after its foundation. Fraenkel was to spend the rest of his career at the Hebrew University, being appointed the first Dean of the Faculty of Mathematics, and serving as the rector of the university for a period.

Fraenkel's first work was on Hensel 's p-adic numbers and on the theory of rings. However he is best known for his work on set theory, writing his first major work on the topic Einleitung in die Mengenlehre in 1919.

He made two attempts, in 1922 and 1925, to put set theory into an axiomatic setting that would avoid the paradoxes. He tried to improve the definitions of Zermelo and, within his axiom system, he proved the independence of the axiom of choice . His system of axioms was modified by Skolem in 1922 to give what is today known as the ZFS system. This is named after Zermelo , Fraenkel and Skolem . Within this system it is harder to prove the independence of the axiom of choice and this was not achieved until the work of Cohen in 1963.

Fraenkel was also interested in the history of mathematics and wrote a number of important works on the topic. He wrote on Gauss 's work in algebra in 1920, then in 1930, he published an important biography of Cantor . In 1960 he published Jewish mathematics and astronomy.

A number of Fraenkel's students have made important contributions to mathematics including Robinson who succeeded him when he retired from his chair at the Hebrew University. After retiring Fraenkel did not give up teaching, continuing to lecture at Bar Ilan University, near Tel Aviv.

We have already mentioned that Fraenkel was a fervent Zionist. As such he was involved in political activity being a member of the Vaad Leumi, the executive committee of the Palestinian Jewish National Assembly at the time of British mandate. Fraenkel was also a member of the Merkaz Ruhani religious movement within Zionism. This party promoted Jewish religious education, established religious schools and strongly promoted the authority of the chief rabbinate over all Jewish matters such as marriage and divorce.

Source:School of Mathematics and Statistics University of St Andrews, Scotland