# Yury Yershov

**Yuri L. Ershov** or **Yershov** (Юрий Леонидович Ершов, born 1 May 1940 ) is a Soviet and Russian mathematician.

Yuri L. Ershov | |
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In his office. 2017 | |

Born | |

Alma mater | Novosibirsk State University |

Scientific career | |

Fields | Mathematics |

Yuri Ershov was born in 1940 in Novosibirsk. In 1958 he entered the Tomsk State University and in 1963 graduated from the Mathematical Department of the Novosibirsk State University. In 1964 he has successfully defended his PhD thesis "Decidable and Undecidable Theories" (advisor Anatolij Mal'tsev). In 1966 he has successfully defended his DrSc thesis "Elementary Theory of Fields" (Элементарные теория полей).

Apart from being a mathematician, Ershov was a member of the communist party and had different distinguished administrative duties in Novosibirsk State University. Ershov has been accused of antisemitic practices, and his visit to the U.S. in 1980 drew public protests by a number of U.S. mathematicians.[1] Ershov himself denied the validity of these accusations.

Yuri Ershov is a member of the Russian Academy of Sciences, professor emeritus of Novosibirsk State University [2] and a former Rector of the Novosibirsk State University.[3][4]

He has been working at the Sobolev Institute of Mathematics since 1963. Currently he is Director of this Institute (since 2003). In 1968 he has got a title of Full Professor. In 1970 he was elected to be a Correspondent Member of the Academy of Sciences of the USSR, in 1990 he became Full Member (Academician) of the Russian Academy of Sciences. In 1964-2002 he worked at the Novosibirsk State University (as second job): in 1968-2002 as a professor, in addition, in 1973-1976 he was Dean of the Mathematical Department of the Novosibirsk State University and Rector of this university in 1985-1993. Yuri L. Ershov is Editor in Chief of the Siberian Mathematical Journal and Editor in Chief of the journal Algebra i Logika (Algebra and Logic).

His basic scientific interests are: algebra, field theory, mathematical logic, algorithm theory, model theory, constructive models, computer science and philosophical aspects of mathematics. He proved decidability of the elementary theory of the field of p-adic numbers (independently proven by J.Ax and S.Kochen), undecidability of the elementary theory of finite symmetric groups, decidability of the elementary theory of relatively complemented distributive lattices.

Yuri Ershov is a Laureate of Malcev's Award of the Russian Academy of Sciences (1992), Russian State Award in the area of Science and Technics (2002,2003), and Lavrentjev's Foundation Award (2007), is decorated with several Russian State Orders. In 2013 he won the Demidov Prize. He was an invited speaker at the International Congress of Mathematicians in 1966 at Moscow with talk *Elementary theories of fields*[5] and in 1970 at Nice with talk *La theorie des enumerations*.

## Selected works

*Definability and Computability*. 1996.*Multi-Valued Fields*. 2001.- "Local class field theory".
*St. Petersburg Math. J*.**15**: 837–846. 2004. MR 2044630. - "Tame and purely wild extensions of valued fields".
*St. Petersburg Math. J*.**19**: 765–773. 2008. MR 2381943.

## References

- Anita Burdman Feferman and Solomon Feferman, Alfred Tarski: Life and Logic. Cambridge University Press, 2004, ISBN 0-521-80240-7; pp. 363–365
- Professors emeritus of Novosibirsk State University
- S. S. Goncharov, I. A. Lavrov and V. D. Mazurov. Yuri Leonidovich Ershov (on his 60th birthday). Russian Mathematical Surveys, vol. 55 (2000), no. 6, pp. 1193-1204
- Ershov Yurii Leonidovich. Bio page, Russian Academy of Sciences. Accessed December 20, 2009.
- Aizerman, M. A. (1968). "Elementary theories of fields by Ju. L. Eršov".
*Thirty-one invited addresses at the International Congress of Mathematicians in Moscow, 1966*. American Mathematical Soc.**70**: 39.