**Aleksandr Danilovic Aleksandrov** was a Russian mathematician and physicist who worked in geometry and a wide variety of areas of physics. He wrote many textbooks.

- Of course this is not strictly true, since when Aleksandrov was two years old St Petersburg changed its name to Petrograd.
- Aleksandrov attended school in Petrograd but while he was at school the name of the city in which he lived changed yet again and so by the time he left school in 1928 it was a Leningrad school from which he graduated.
- When Aleksandrov left school he did not intend to study mathematics but rather his interests were in physics.
- However Aleksandrov was taught mathematics in the Faculty of Physics by B N Delone.
- Delone's interests in the geometry of numbers and the structure of crystals soon began to attract Aleksandrov at least as much as his work in physics which was supervised by V A Fok.
- In 1932 Aleksandrov moved from the Optics Institute to Physics Research Institute of Leningrad University where he worked on the theoretical side of the subject.
- The influence of these two are clearly seen in Aleksandrov's first few publications which appeared in 1933 and 1934 and represented research largely carried out while he was still an undergraduate.
- While continuing to work at the Physics Research Institute, Aleksandrov began to teach in the Faculty of Mathematics and Mechanics from 1933.
- Aleksandrov's doctoral thesis (more of a habilitation thesis) was presented in 1937 and in it he studied the topics of additive set functions and the geometrical theory of weak convergence.
- Aleksandrov was appointed as Professor of Geometry at Leningrad University in 1937.
- In 1934 the Steklov Mathematical Institute had been set up but moved to Moscow and Delone, Aleksandrov's supervisor, had moved with it to head the Algebra Department.
- In 1940 the Leningrad Branch of the Mathematical Institute was founded and it had among its members Aleksandrov, Kantorovich, Linnik, and Faddeev.
- In 1944 Aleksandrov returned to the University of Leningrad where he was Professor of Geometry.
- Both of Aleksandrov's supervisors, Fok and Delone, played major roles in the Physical and Mathematical Society.
- Then Smirnov organised the Leningrad Mathematical Seminar in 1953 which went some way to filling the gap left but both Aleksandrov and Smirnov worked hard to restart the Leningrad Mathematical Society.
- In 1964 Aleksandrov left Leningrad and moved to Novosibirsk where he was appointed as Head of the Department of Geometry of the University of Novosibirsk.
- In order to solve concrete problems Aleksandrov had to replace the Gaussian geometry of regular surfaces by a much more general theory.
- Aleksandrov constructed a theory of intrinsic geometry of convex surfaces on that basis.
- Because of the depth of this theory, the importance of its applications and the breadth of its generality, Aleksandrov comes second only to Gauss in the history of the development of the theory of surfaces.
- Aleksandrov's work in physics did not stop in his student days.
- Finally let us note some of Aleksandrov's interests outside mathematics.
- Aleksandrov received many awards for his major contributions to geometry.

Born 4 August 1912, Volyn, Ryazan, Russia. Died 27 July 1999, St Petersburg, Russia.

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Origin Russia

**Oâ€™Connor, John J; Robertson, Edmund F**: MacTutor History of Mathematics Archive