**Georgii Pfeiffer** did important work on partial differential equations.

- In fact, when Pfeiffer entered the Gymnasium Georgy Voronoy was still a pupil there showing his brilliance by publishing a paper while still at the Gymnasium.
- After graduating from the Pryluka Gymnasium, Pfeiffer entered the Faculty of Physics and Mathematics of Kiev University.
- Among Pfeiffer's lecturers at Kiev University we mention Mikhail Egorovich Vashchenko-Zakharchenko, Boris Yakovlevic Bukreev and, in particular, Vasilii Petrovich Ermakov (1845-1922).
- Pfeiffer graduated from the University of Kiev in 1896 and was then appointed as a secondary school mathematics teacher in a Gymnasium in Kiev.
- In Kiev, Pfeiffer lived in an apartment in a complex of residential buildings on Khmelnitsky Street.
- Elected to the Academy of Sciences of the Ukraine in 1920, Pfeiffer chaired the Commission on Pure Mathematics from that time.
- Pfeiffer was also attached to the Institute of Mathematics of the Academy of Sciences of the Ukraine in Kiev and served as Director during two periods, namely 1934 to 1941 and again from 1944 until his death in 1946.
- The Molotov-Ribbentrop non-aggression pact between Germany and the Soviet Union meant that the initial years of the war had little effect on life in Kiev and Pfeiffer continued his work there.
- In the three years 1941-44, Pfeiffer was in Ufa, the capital of the Bashkortostan republic in western Russia.
- In Ufa, Pfeiffer was Director of the Institute of Mathematics and Physics.
- By the end of 1943 Soviet troops had liberated Kiev and in the following year Pfeiffer returned to the city when the Ukrainian Academy of Sciences returned.
- Pfeiffer's first research was on the problem of solving equations by radicals, and he next looked at algebraic geometry.
- some work of the Ukrainian mathematician G V Pfeiffer , showing how to find integrals of a general system of partial differential equations by using sequential complete systems instead of passing to Jacobian systems.
- Pfeiffer also constructed all the infinitesimal operators of a system of equations.
- Koval'chuk explains how Pfeiffer's methods greatly expanded the class of integrable systems, but have been neglected over the past half-century as functional-analytic methods have been in fashion.
- In total, Pfeiffer published 250 scientific papers in several languages including Ukrainian, Russian, French and German.
- Pfeiffer was a great connoisseur of mathematical literature in many different areas of mathematics showing himself to be a scholar with deep feelings and high standards in everything he did.

Born 24 October 1872, Sokyryntsi, Pryluka, Poltava gubernia, Ukraine. Died 10 September 1946, Kiev, Ukranian SSR (now Kyiv, Ukraine).

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Origin Ukraine

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