The conference topics are traditionally associated with various interrelated areas of fundamental mathematics: aspects of harmonic analysis and operator theory, elliptic equations, approximation theory, theory of partial differential equations, models and methods in probability theory and others.

The conference was held with the involvement of leading experts and participants from various regions of Russia, as well as from Belarus, Armenia, Serbia, the UAE, India, Cameroon, Iran, Ecuador, Italy, Georgia, Tajikistan and other countries.

During the conference, 4 parallel sections worked: Functional analysis, operator theory and approximation theory; Differential equations and mathematical physics; Probabilistic-analytical models and methods; a special section dedicated to the memory of S.B. Klimentov.

The conference program included reports by invited experts, as well as speeches by 16 young scientists in the framework of sections.

The organizer of the conference and the chairman of the Program Committee of the conference is Alexey Karapetyants, Doctor of Ph.D., Director of the RSC SFedU, Professor of the SFedU Institute of Mathematics, Mechanics and Computer Science. The conference is included in the Development Program of the Regional Scientific and Educational Mathematical Center of the Southern Federal University and is supported by the relevant project of the Ministry of Education and Science of Russia, Agreement No. 075-02-2023-924. A significant number of participants, including young scientists and plenary lecturers, received financial support to participate in the conference.

Plenary lecturers of the conference: Alexey Karapetyants (Russia/Rostov-on-Don), Adolf Mirotin (Belarus), Narayanan Krishnan (India), Alexander Buffetov (Russia/Moscow), Andrey Muravnik (Russia/Moscow), Francesco Mainardi (Italy), Konstantin Fedorovsky (Russia/Moscow), Apushkinskaya Darya (Russia/Moscow), Leonid Rossovsky (Russia/Moscow), Natalia Smorodina (Russia/With.Petersburg), Alexander Soldatov (Russia/Moscow), Yuri Gliklikh (Russia/Voronezh), Vyacheslav Yurko (Russia/Saratov), Arsenovich Milos (Serbia), Armen Jrbashyan (Armenia), Maria Skopina (Russia/With.St. Petersburg), Ilolov Mamadsho (Tajikistan), Kusraeva Zalina (Russia/Vladikavkaz), Vagharshakyan Armen (Armenia), Khouri Suheil (UAE).

The lectures of the plenary lecturers were recorded and after due revision will be posted on the Internet on the conference channel (https://www.youtube.com/channel/UCMC1h55SjWn5hkRShZ7fhEw )

Selected articles of OTHA-2023 participants will be considered for publication in the scientific journal Journal of Mathematical Sciences (Series A) - Editor-in-Chief A.N. Karapetyants.

As already noted, one of the sections of the conference was also dedicated to the memory of the famous Russian mathematician, Doctor of Physical and Mathematical Sciences, Professor Sergei Borisovich Klimentov, who passed away on February 10, 2023. He published about 200 scientific and methodological works, including several monographs and more than 100 articles in leading mathematical journals of Russia and the world. The diversity and depth of S.B. Klimentov's scientific activity were reflected and fruitfully applied in his teaching work. He was a lecturer on a wide range of classical university courses (analytical geometry, differential geometry, mathematical analysis, theory of functions of a complex variable, topology, probability theory and mathematical statistics, theory of random processes, geometry of manifolds), developed and taught unique author's special courses (minimal surfaces, theory of bending, partial differential equations, bending polyhedra, generalized analytic functions, additional chapters of the theory of surfaces, foundations of geometry, Riemannian geometry).

In order to introduce the guests to the ethnography, history and traditions of the Don Region, the organizers of the conference held a boat tour along the Don River with the participation of the Cossack folk song ensemble and an excursion to the village of Starocherkasskaya.