|Died||October 15, 1965 (aged 74)|
|Alma mater||University of Marburg|
|Known for||Zermelo–Fraenkel axioms|
|Awards||Israel Prize (1956)|
|Institutions||Hebrew University of Jerusalem|
|Doctoral advisor||Kurt Hensel|
Abraham Fraenkel (Hebrew: אברהם הלוי (אדולף) פרנקל; February 17, 1891 – October 15, 1965) was a German-born Israeli mathematician. He was an early Zionist and the first Dean of Mathematics at the Hebrew University of Jerusalem. He is known for his contributions to axiomatic set theory, especially his additions to Ernst Zermelo's axioms, which resulted in the Zermelo–Fraenkel set theory.
Abraham Adolf Halevi Fraenkel studied mathematics at the Universities of Munich, Berlin, Marburg and Breslau. After graduating, he lectured at the University of Marburg from 1916, and was promoted to professor in 1922.
In 1919 he married Wilhelmina Malka A. Prins (1892–1983). Due to the severe housing shortage in post-First World war Germany, for a few years the couple lived as subtenants at professor Hensel's place.
After leaving Marburg in 1928, Fraenkel taught at the University of Kiel for a year. He then made the fateful choice of accepting a position at the Hebrew University of Jerusalem, which had been founded four years earlier, where he spent the rest of his career. He became the first Dean of the Faculty of Mathematics, and for a while served as Rector of the University.
Fraenkel was a fervent Zionist and as such was a member of Jewish National Council and the Jewish Assembly of Representatives under the British mandate. He also belonged to the Mizrachi religious wing of Zionism, which promoted Jewish religious education and schools, and which advocated giving the Chief Rabbinate authority over marriage and divorce.
Fraenkel's early work was on Kurt Hensel's p-adic numbers and on the theory of rings. He is best known for his work on axiomatic set theory, publishing his first major work on the topic Einleitung in die Mengenlehre (Introduction to set theory) in 1919. In 1922 and 1925, he published two papers that sought to improve Zermelo's axiomatic system; the result is the Zermelo–Fraenkel axioms. Fraenkel worked in set theory and foundational mathematics.
Fraenkel also was interested in the history of mathematics, writing in 1920 and 1930 about Gauss's works in algebra, and he published a biography of Georg Cantor. After retiring from the Hebrew University and being succeeded by his former student Abraham Robinson, Fraenkel continued teaching at the Bar Ilan University in Ramat Gan (near Tel Aviv).