Институт математики и математического моделирования

Date: Tuesday, June 9 , 2026

Time: 14.00-15.00 (Istanbul) = 13.00-14.00 (Ghent) = 16.00-17.00 (Almaty)

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

Speaker:
Prof. Dr. Alexander Plakhov

Center for R&D in Maths and Appl., University of Aveiro, Portugal

Title: Extremal problems in billiards

Abstract: We consider the billiard in the exterior of a body — a compact set in Rn (n≥ 2) with piecewise smooth boundary. Within this model, we consider Newton-like problems of minimal aerodynamic resistance in a particular direction and minimal resistance averaged over all directions. It turns out [1] that there are bodies with zero resistance, and also (using an optical analogy) bodies invisible in one direction.

It is known [3, 2] that bodies with zero resistance in all directions, and hence, perfectly (in all directions) invisible bodies do not exist. We consider the problem of least average resistance for a body of fixed volume contained in a unit sphere. This problem has not been completely solved. A lower bound for the average resistance, which is a function of body volume, is found [4]. This result is obtained using methods of the vector-valued problem of optimal mass transport.

Biography:

Alexander Plakhov is Associate Professor at the University of Aveiro, Portugal. He got his Ph.D. in 1986 and Dr. Sci. in 2011 at the Moscow State University and his habilitation at the University of Aveiro. He is the coordinator of the research group Optimization, Graph Theory and Combinatorics at CIDMA (Center for Research & Development in Mathematics and Applications) at the University of Aveiro. The research interests of Alexander Plakhov focus on dynamical systems and optimization. Many of his important results are at the intersection of Newton’s problem of minimal resistance with theories of billiards, optimal mass transport, Kakeya problem, and classical geometry. This research has found interesting applications in geometric optics; the discovery of various kinds of invisible bodies and retroreflectors should be mentioned. In mechanics, the Magnus effect for spinning bodies in highly rarefied media has been studied.

References

[1] A. Aleksenko and A. Plakhov. Nonlinearity 22, 1247-1258 (2009).

[2] A. Plakhov. Exterior billiards. Systems with impacts outside bounded domains. Springer, New York, 2012. xiv+284 pp. ISBN: 978-1-4614-4480-0

[3] A. Plakhov and V. Roshchina. Invisibility in billiards. Nonlinearity 24, 847-854 (2011).

[4] A. Plakhov and V. Roshchina. The problem of optimal camouflaging. SIAM J. Math. A**l. 57, 95-117 (2025).

Date: Tuesday, June 2 , 2026

Time: 14.00-15.00 (Istanbul) = 13.00-14.00 (Ghent) = 16.00-17.00 (Almaty)

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

Speaker: Prof. Dr. Arsen Pskhu

Institute of Applied Mathematics and Automation of Kabardino-Balkarian Scientific Center of the Russian Academy of Sciences, Russia

Title: Order determination inverse problems for fractional diffusion-wave equations with Dzhrbashyan-Nersesyan operator

Abstract: The talk discusses inverse problems for the fractional diffusion equation with the Dzhrbashyan–Nersesyan derivative. The goal is to determine both order and form of fractional differentiation. Overdetermination conditions are based on integral identities relating solutions of the Cauchy problem to solutions of the Helmholtz equation and to entire harmonic functions. Both spatially oriented conditions (at fixed times) and asymptotic conditions (for large times) are used. The unique solvability of the inverse problems is proved.

Biography:
Arsen Pskhu graduated from Lomonosov Moscow State University (1991), defended his PhD thesis in 1999 (Frankl Problems for Mixed-Type Equations), and defended his doctoral thesis in 2007 (Boundary Value Problems for Partial Differential Equations of Fractional and Continual Order). His research interests include fractional calculus, ordinary and partial differential equations of integer and fractional order, integral transforms, and the theory of special functions.

026 жылғы 2-маусым Сейсенбі күні сағат 14:00-де «Математикалық зерттеулердегі жасанды интеллект» семинары онлайн форматта өтеді.

Баяндамашы: Б. Сәбитбек

Тақырып: Жасанды интеллект көмегімен математика саласындағы гранттық өтінімдерді жазу

Семинарға барлық ғылыми қызметкерлер, докторанттар мен магистранттар шақырылады.

Семинардың Zoom cілтемесі
https://us06web.zoom.us/j/9049890435?pwd=6RpQfVgCeKxqH3mrq3mFabmefIS1Sr.1

Конференция идентификаторы: 904 989 0435
Кіру коды: 1100

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Городской научный семинар
«Дифференциальные операторы и их приложения»

Институт математики и математического моделирования, каб. 306,

15:00 (Алматы, GMT+5), 28 мая 2026

Трансляция семинара в Zoom

https://us02web.zoom.us/j/6678270445?pwd=SFNmQUIvT0tRaHlDaVYrN3l5bzJVQT09

Идентификатор конференции: 667 827 0445, Код доступа: 1

Руководители семинара:
академик НАН РК М. Отелбаев, академик НАН РК Т.Ш. Кальменов, профессор Б.Е. Кангужин, член-корр. НАН РК М.А. Садыбеков

Докладчик: Берікбол Төребек, Профессор

Институт математики и математического моделирования

Тема: «Parabolic problems whose Fujita critical exponent is not given by scaling»,

Абстракт: This work investigates the heat equation with a nonlocal power-law nonlinearity involving a Riesz potential. We introduce the Fujita-type critical exponent, which characterizes the global behavior of solutions: global existence for small initial data in supercritical case, and finite-time blow-up critical and subcritical cases. It is remarkable that the critical Fujita exponent is not determined by the usual scaling argument, but instead arises in an unconventional manner, similar to the results of Cazenave et al. [Nonlinear A**lysis, 68 (2008), 862-874] for the heat equation with a time-nonlocal nonlinearity. The result on global existence, provides a positive answer to the hypothesis proposed by Mitidieri and Pohozaev in [Proc. Steklov Inst. Math., 248 (2005) 164-185]. We further establish global nonexistence results for the above heat equation, where the Riesz potential term is replaced by a more general convolution operator, thereby extending the Mitidieri-Pohozaev's results established in the aforementioned work. Proofs of the blow-up results are obtained using a nonlinear capacity method specifically adapted to the structure of the problem, while global existence is established via a fixed-point argument combined with the Hardy-Littlewood-Sobolev inequality. The main results are a joint work with A. Z. Fino, which was recently published in Calculus of Variations and Partial Differential Equations.

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Приглашаем Вас принять участие в нашей очередной конференции 8th ICAAM 2026,
которую мы проводим с 26 сентября по 3 октября, в Турции, Kemer–Antalya, Türkiye.

Для участия в конференции вам нужно пройти регистрацию на нашу конференцию на сайте.

http://www.icaam-online.org/

Городской научный семинар
«Дифференциальные операторы и их приложения»

Институт математики и математического моделирования, каб. 306,

15:00 (Алматы, GMT+5), 21 мая 2026

Трансляция семинара в Zoom

https://us02web.zoom.us/j/6678270445?pwd=SFNmQUIvT0tRaHlDaVYrN3l5bzJVQT09

Идентификатор конференции: 667 827 0445, Код доступа: 1

Руководители семинара:
академик НАН РК М. Отелбаев, академик НАН РК Т.Ш. Кальменов, профессор Б.Е. Кангужин, член-корр. НАН РК М.А. Садыбеков

Докладчик: Қанат Төленов, Профессор

Институт математики и математического моделирования

Тақырыбы: «Көпөлшемді Гильберт түрлендіруінің оптималды бағалаулары»,

Тема: « Оптимальные оценки многомерного преобразования Гильберта»,

Абстракт: В этом докладе мы получаем верхние и нижние распределительные оценки для многомерного преобразования Гильберта.

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2026 жылғы 20 мамыр, сәрсенбі күні сағат 15:00-де Математика және математикалық модельдеу институтының 306-кабинетінде «Математикалық зерттеулердегі жасанды интеллект» семинары өтеді.

Баяндамашылар:
Б. Төребек, «Математикалық мәселелерді зерттеудегі жасанды интеллект мүмкіндіктері».
М. Садыбеков «Ғалымның күнделікті жұмысында жасанды интеллектті пайдалану нормаға айналуы керек: математиктер үшін ChatGPT мысалы».

Семинарға барлық ғылыми қызметкерлер, докторанттар мен магистранттар шақырылады.

Семинардың Zoom cілтемесі
https://us06web.zoom.us/j/9049890435?pwd=6RpQfVgCeKxqH3mrq3mFabmefIS1Sr.1

Конференция идентификаторы: 904 989 0435
Кіру коды: 1100

20 мая 2026 года, в среду, в 15:00, в кабинете 306 Института математики и математического моделирования состоится семинар «Искусственный интеллект в математических исследованиях».

Докладчики:
Б. Торебек, «Возможности искусственного интеллекта при изучении математических проблем».
М. Садыбеков, «Использование ИИ должно стать нормой в повседневной работе ученого: на примере ChatGPT для математиков».

Приглашаются все заинтересованные научные сотрудники, докторанты и магистранты.

Трансляция семинара в Zoom
https://us06web.zoom.us/j/9049890435?pwd=6RpQfVgCeKxqH3mrq3mFabmefIS1Sr.1

Идентификатор конференции: 904 989 0435
Код доступа: 1100

Городской научный семинар
«Дифференциальные операторы и их приложения»

Институт математики и математического моделирования, каб. 306,

15:00 (Алматы, GMT+5), 14 мая 2026

Трансляция семинара в Zoom

https://us02web.zoom.us/j/6678270445?pwd=SFNmQUIvT0tRaHlDaVYrN3l5bzJVQT09

Идентификатор конференции: 667 827 0445, Код доступа: 1

Руководители семинара:
академик НАН РК М. Отелбаев, академик НАН РК Т.Ш. Кальменов, профессор Б.Е. Кангужин, член-корр. НАН РК М.А. Садыбеков

Докладчик: Vladimir Mityushev, Professor

Faculty of Computer Science and Mathematics,
Krakow University of Technology, Poland

Тема: «A**lytical RVE theory of dispersed structures and its application»,

Абстракт: The talk introduces an approach inspired by structural sums, which describes the macroscopic anisotropy and interactions among inclusions of dispersed heterogeneous media. The structural sums serve as the cornerstone for mathematical models of random structures within the framework of the analytical Representative Volume Element (aRVE) theory. We quantified the inter-phase interactions within media and derived analytical formulas for their macroscopic properties based on the R-linear problem for analytic functions.

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Date: Tuesday, May 5, 2026

Time: 14.00-15.00 (Istanbul) = 13.00-14.00 (Ghent) = 16.00-17.00 (Almaty)

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

Speaker:
Assoc. Prof. Dr. Yagub N. Aliyev
ADA University, Baku, Azerbaijan

Title: Sturm-Liouville problems with a boundary condition depending linearly on an eigenparameter

Abstract: This paper studies a Sturm-Liouville boundary value problem in which one of the boundary conditions depends linearly on the spectral parameter. The differential equation is considered on the interval with a classical boundary condition at one endpoint and an eigenparameter--dependent boundary condition at the other. Explicit formulas for the inner products and norms of eigenfunctions are obtained. These relations make it possible to analyze the structure of the system of root functions and the corresponding biorthogonal system. Using these results, the minimality of the system of root functions in L2(0,1) is established. Furthermore, the basis properties of the system of root functions in the spaces Lp(0,1), are investigated. Necessary and sufficient conditions under which the system forms a basis are derived. Special attention is given to the cases of multiple eigenvalues and the case when the eigenvalue coincides with the critical value -d/c. The obtained results reveal a symmetry between different spectral cases and provide a simpler approach that avoids the use of the exit spaces. Several examples are presented to illustrate the theoretical results.

Biography:

Yagub Aliyev is an Associate Professor at ADA University (Azerbaijan). His research interests include Sturm-Liouville theory, 3x+1 Problem, History of Mathematics, Number theory, Euclidean Geometry, Inequalities.

Городской научный семинар
«Дифференциальные операторы и их приложения»

Институт математики и математического моделирования, каб. 306,

15:00 (Алматы, GMT+5), 30 апреля 2026

Трансляция семинара в Zoom

https://us02web.zoom.us/j/6678270445?pwd=SFNmQUIvT0tRaHlDaVYrN3l5bzJVQT09

Идентификатор конференции: 667 827 0445, Код доступа: 1

Руководители семинара:
академик НАН РК М. Отелбаев, академик НАН РК Т.Ш. Кальменов, gрофессор Б.Е. Кангужин, член-корр. НАН РК М.А. Садыбеков

Докладчик: Бауыржан Дербісалы, PhD
(Институт математики и математического моделирования)

Тема: «Асимптотическое поведение собственных значений задачи Стеклова в тонкой мультиобласти»,

«Asymptotic behavior of the eigenvalues of the Steklov problem in a thin multidomain»

Абстракт: Этот доклад посвящён асимптотическому поведению собственных значений классической задачи Стеклова в тонкой мультиобласти при её постепенном сужении. Тонкая мультиобласть состоит из двух вертикальных цилиндров, расположенных один над другим.

Мы показываем, что собственные значения стремятся к нулю при утончении области. В этом случае предельная спектральная задача в верхнем цилиндре соответствует одномерной задаче на собственные значения, тогда как предельная задача в нижнем цилиндре задаётся в (n-1)-мерном шаре.

В завершение исследования мы рассматриваем случай, когда степень утончения верхнего и нижнего цилиндров одинакова.

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