[Turkmath:5350] (no subject)

Tue Jan 4 08:01:14 UTC 2022

*Bahçeşehir University, Istanbul, Turkey*

*Analysis & PDE Center, Ghent University, Ghent,  Belgium *

*Institute Mathematics & Math. Modeling, Almaty, Kazakhstan*

Seminar leaders: Prof. Allaberen Ashyralyev BAU, Istanbul), Prof. Michael
Ruzhansky (GU,  Ghent),

Prof. Makhmud Sadybekov (IMMM, Almaty)

Date: Tuesday, January 11, 2022   Time: 13.00-14.00 (GMT+4, Istanbul) =
10.00-11.00 (Ghent) = 15.00-16.00 (Almaty)

*Zoom link*: *https://us02web.zoom.us/j/6678270445?pwd=SFNmQUIvT0tRaH-*
<https://us02web.zoom.us/j/6678270445?pwd=SFNmQUIvT0tRaHlDaVYrN3l5bzJVQT09>
*lDaVYrN3l5bzJVQT09*
<https://us02web.zoom.us/j/6678270445?pwd=SFNmQUIvT0tRaHlDaVYrN3l5bzJVQT09>*,
Conference ID: *667 827 0445, *Access code: *1

*Speaker:*
*Prof. Dr. T.Sh. Kal’menov* Institute of Mathematics and Mathematical
Modeling, Almaty, Kazakhstan *Title:* Hadamard's example and solvability of
the mixed Cau chy problem for the multidimensional Gellerstedt equation

*Abstract:* In the theory of partial differential equations, an example
constructed by J. Hada- mard, which shows the instability of the solution of
the Cauchy problem for the Laplace equa- tion with respect to small changes
in the initial data, is of great importance. In the works of A.N.Tikhonov,
V.Y.Arsenin, M.M.Lavrentiev and many subsequent papers, this problem is reduced
to integral equations of the first kind by solving the Newton potential,
various regu- larizations of the problem under consideration are given and
its conditional correctness is established. In our previous work, a
criterion for the strong solvability of the Cauchy problem for the Laplace
equation was found by the spectral decomposition of the Laplace operator
with a deviating argument.

In this report, we consider a mixed Cauchy problem for two-dimensional and
multidimen- sional degenerate Gellerstedst equations. Analogs of the
Hadamard’s example are constructed and incorrectness of the solution of the
Cauchy problem for the Gellerstedt equation in two- dimensional and
multidimensional cases is established. The condition of strong solvability
of the mixed Cauchy problem for the multidimensional Gellerstedt equation in
a cylindrical do- main is found. The proof is based on the spectral
properties of the Laplace operator and the properties of special functions.

*Biography:*

Tynysbek Kal’menov is a graduate of the Novosibirsk State University
(1969), and a representative of the school of A.V. Bitsadze, the
outstanding scientist, the corresponding member of the Academy of Sciences
of the USSR. In 1972, he completed his postgraduate studies at the Institute
of Mathematics of the Siberian Branch of the Academy of Sciences of the
USSR. In 1983, he defended his doctoral thesis at Moscow State University.
In 1989, he was elected as a corresponding member of the Academy of Sciences of
the Kazakh SSR.

Tynysbek Kal’menov worked at the Institute of Mathematics and Mechanics of
the Academy of Sciences of the Kazakh SSR (1972-1985). From 1986 to 1991, he
was the dean of the Faculty of Mathematics of Al-Farabi Kazakh State
University. From 1991 to 1997, he was the rector of Kazakh
Chemical-Technological
University (Shymkent).

>From 2004 to 2019, Tynysbek Kal’menov was the General Director of the
Institute of Mathematics and Mathematical Modeling, he made it one of the
leading scientific centres in the country and the best research institute
in Kazakhstan. Suffice it to say, that in terms of the number of scientific
publications (2015-2018) in international rating journals indexed in the Web
of Science, the Institute of Mathematics and Mathematical Modeling ranked
fourth among all Kazakhstani organisations, behind only three large
universities: Nazarbaev Univer sity, N Al-Farabi National University and
L.N. Gumilyov Eurasian University.

Since 2019, Tynysbek Kal’menov has been working as the head of the
Department of Differential Equations of the Institute of Mathematics and
Mathematical Modeling.

In 2013, he was awarded the State Prize of the Republic of Kazakhstan in
the field of science and technology for the series of works “To the theory
of initial-boundary value problems for differential equations”.

The main areas of scientific interests of Academician Tynysbek Kal’menov
are differential equations, mathematical physics and operator theory. He has
obtained fundamental scientific results, many of which led to the creation
of new scientific directions in mathematics.

Tynysbek Kal’menov has trained 11 doctors and more than 60 candidates of
sciences and PhD, has founded a large scientific school on equations of
mixed type and differential operators recognized all over the world. Many
of his disciples are major independent scientists recog- nized in the world of
mathematics.

He has published over 150 scientific articles, most of which are published
in international mathematical journals, including 14 articles published in
“Doklady AN SSSR/ Doklady Math- ematics”. In the last 5 years alone
(2016-2020), he has published more than 30 articles in scientific journals
indexed in the Web of Science database. To date, Academician Tynysbek
Kal’menov has a Hirsch index of 18 in the Web of Science and Scopus
databases, which is the highest indicator among all Kazakhstan
mathematicians.

*Prof. Dr. Allaberen Ashyralyev *
*Department of Mathematics, Bahcesehir University, 34353, Istanbul, Turkey*
*  and **Near East University, Lefkoşa(Nicosia), Mersin 10 Turkey*
*Peoples' Friendship University of Russia (RUDN University),** Ul Miklukho
Maklaya 6, Moscow 117198, Russian Federation *
*Institute of Mathematics and Mathematical Modelling, 050010, Almaty,
Kazakhstan*
*e-mail: allaberen.ashyralyev at eng.bau.edu.tr
<allaberen.ashyralyev at neu.edu.tr> and **aallaberen at gmail.com
<aallaberen at gmail.com>    *
*http://staff.neu.edu.tr/allaberen.ashyralyev/
<http://staff.neu.edu.tr/allaberen.ashyralyev/>*
https://content.sciendo.com/view/journals/ejaam/ejaam-overview.xml
*icaam-online.org <http://icaam-online.org>*

*https://www.genealogy.math.ndsu.nodak.edu/id.php?id=95872&fChrono=1
<https://www.genealogy.math.ndsu.nodak.edu/id.php?id=95872&fChrono=1>*
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