**Alexander Weinstein** is famed for solving a variety of boundary value problems which have been used in a wide range of applications. He spent a large part of his life suffering discrimination and fleeing from persecution which he successfully survived physically but paid a price mentally.

- It was there that Alexander completed his schooling, studying first in Würzburg, and then at the University of Göttingen during 1913/14.
- Leaving Göttingen, Weinstein moved to Zürich and he continued his interest in astronomy carrying out observations the Federal Observatory.
- Weyl realised that his student Weinstein was extraordinarily talented and tried to put him in contact with leading mathematicians so that he could gain further experience.
- Weinstein ended up working as an assistant of Leon Lichtenstein at the University of Leipzig in 1922.
- This was despite Weinstein becoming a Swiss citizen.
- Weyl recommended Weinstein for a Rockefeller Fellowship and, after this was awarded, Weinstein spent 1926 and 1927 in Rome working with Tulio Levi-Civita.
- That it was natural for him to want to work with Levi-Civita can be seen from the introduction to Ein hydrodynamischer Unitätssatz Ⓣ(A hydrodynamic unity theorem) and, as Weyl expected, it was particularly important in Weinstein's development as a leading researcher in hydrodynamics.
- In 1926, Weinstein published Sur la vitesse de propagation de l'onde solitaire Ⓣ(On the speed of propagation of the solitary wave), Sur les jets liquides à parois données Ⓣ(On liquid jets with given walls), and Sur la représentation analytique de certains mouvements apériodiques Ⓣ(On the analytical representation of certain aperiodic movements ), all in the Rendiconti Accademia Nazionale dei Lincei.
- Later in 1928 Weinstein moved from Hamburg to Breslau and, by 1933, he was being sought by Albert Einstein as a collaborator in Berlin with the two under active discussion.
- However 1933 was the year that the Nazis came to power and Weinstein, being of Jewish background, could not remain in Germany.
- One might wonder why when Weinstein already had a doctorate, he should choose to present himself for a second one.
- Dr Weinstein never considered going back to Russia, even though he went through some years of extreme hardship as an exile.
- Weinstein and Martin founded the Institute of Fluid Dynamics and Applied Mathematics at Maryland in 1949.
- Weinstein's research covered a wide range of topics.
- Weinstein's method was developed to give accurate bounds for eigenvalues of plates and membranes.
- In 1972 Weinstein, together with William Stenger, published the book Methods of intermediate problems for eigenvalues.
- In 1978 Weinstein was eighty years old and Joe D Diaz edited "Selecta", a volume of Weinstein's writings.
- The papers on eigenvalue problems cover the early development of the famous Weinstein method, the joint work with N Aronszajn developing the general theory of intermediate problems, and the Weinstein maximum-minimum theorem.
- Besides the collection of papers, there are biographical notes on Weinstein by the editor, J B Diaz, including a brief discussion of Weinstein's major contributions, and there is a complete list of Weinstein's one hundred two published articles.
- Among the honours given to Weinstein we note that, in addition to the Selecta, two other books were dedicated to him, namely Proceeding of the Conference on Differential Equations (University of Maryland, 1965), edited by J B Diaz and L E Payne, and the book by S Gould, Variational Methods for Eigenvalue Problems: An Introduction to the Weinstein Method of Intermediate Problems (1957).
- After retiring in 1967, Weinstein continued research at the American University in Washington D.C., then, from 1968 to 1972 he worked at Georgetown University, also in Washington D.C. Weinstein died on 6 November 1979, following a surgical operation a few days earlier in a Washington D.C. hospital.
- Weinstein, as a mathematician, was certainly "a citizen of the world." But even outside of mathematics his knowledge, especially artistic and literary, was very extensive.

Born 21 January 1897, Saratov, Russia. Died 6 November 1979, Washington DC, USA.

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Astronomy, Origin Russia

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