Institute of Mathematics and Informatics

Семинар на МЦМН
2026-01-20 13:00 - 14:30 (Europe/Sofia) | Институт по математика и информатика – БАН, Block 8, 1113 БАН IV км., София, Bulgaria
Дата и място: Вторник, 20.01.2026 г., 13:00 ч., Зала 403, ИМИ – БАН
Докладчик: Bogdan Đorđević (Serbian Academy of Arts and Sciences)
Заглавие: Applications of Banach algebras and Banach modules to some contemporary analysis problems
Abstract:
In recent years applied mathematics has experienced a historical progress, blurring the lines between the previously clear research paths and directions. Accordingly, contemporary mathematical analysis is at the verge of unifying seemingly different research areas and topics. With this in mind, I’d like to talk about my humble contribution to this cause: my lecture will concern how Banach algebras and modules, combined with spectral theory, functional calculus, and generalized inverses, help in various problems that emerge in applied mathematics in general: from solving operator and matrix equations, to evaluating sums of some Banach-space-valued series, to analyzing some unstable abstract Cauchy problems, and finally to approximating solutions to functional stochastic differential equations.
Допълнителна информация можете да намерите на сайта на семинара:
https://icms.bg/category/icms-seminar/

Семинар на МЦМН
2026-01-27 13:00 - 14:30
Дата и място: Вторник, 27.01.2026 г., 13:00 ч., Зала 403, ИМИ – БАН
Докладчик: Jean-Pierre Gazeau (Université Paris Cité, CNRS, and University of Białystok)
Заглавие: Spectral and angular variables for open qudit dynamics
Abstract: In this talk, I introduce a parametrization of finite-dimensional quantum states that is particularly adapted to the study of open qudit dynamics. Any generic density matrix in Cn can be described by separating spectral variables, which encode the eigenvalue content, from angular variables associated with the unitary degrees of freedom. These angular variables naturally live on the coset space SU(n)/T, in the spirit of the Tilma–Sudarshan construction.
A key outcome of this parametrization is a partial decoupling of the GKLS evolution: while the angular variables are driven by both the Hamiltonian and the dissipative contributions, the spectral variables evolve under the dissipative part only. This separation provides a transparent geometric picture of decoherence and dissipation. Simple examples for qubits and qutrits are discussed, together with an alternative, geometrically motivated notion of purity expressed solely in terms of the spectral variables in a linear way.
Допълнителна информация можете да намерите на сайта на семинара:
https://icms.bg/category/icms-seminar/

Семинар на МЦМН
2026-03-10 13:00 - 14:30, 2026-03-17 13:00 - 14:30
Two lectures by Milen Yakimov,
chair of the group on Cluster Algebras and Quantum Groups at the ICMS, IMI-BAS.

Tuesday, March 10, at 13:00 in room 403, IMI-BAS.
Cluster structures on quantum groups and the full Berenstein-Zelevinsky conjecture

Tuesday, March 17, at 13:00 in room 403, IMI-BAS.
Reflective centres of module categories and quantum K-matrices

Abstracts:
March 10: Cluster Algebras were invented by Fomin and Zelevinsky in the early 2000s and quickly turned into an indispensable tool in many areas of mathematics. In this talk, we will provide a gentle introduction to the subject. From the early days of the theory of cluster algebras, one of the desired constructions was to turn the quantized coordinate rings of complex simple Lie groups into quantum cluster algebras. This remained elusive. We will present a resolution of this conjecture and of the Berenstein-Zelevinsky conjecture on cluster structures on quantum double Bruhat cells. This is a joint work with Fan Qin and Hironori Oya.

March 17: Braided monoidal categories have applications in various situations. In particular, their universal R-matrices give solutions of the quantum Yang-Baxter equation and representations of braid groups of type A. There are powerful methods for constructing them: Drinfeld doubles of Hopf algebras and Drinfeld centres of monoidal categories. On the other hand, universal K-matrices, leading to solutions of the reflection equation and representations of braid groups of type B are much less well understood and there are no general constructions for them. We will describe a construction of reflective centers of module categories. It gives rise to a quantum double construction for universal K-matrices, which can be viewed as a type B analog of Drinfeld’s double construction. This is a joint work with Robert Laugwitz and Chelsea Walton.

More information can be found on the seminar’s web-page:
https://icms.bg/category/icms-seminar/

Семинар на МЦМН
2026-05-12 13:00 - 14:30
Дата и място: Tuesday, May 12-th, 13:00, room 403 IMI-BAS.
Лектор: Ina Petkova (Darmouth College)
Заглавие: Khovanov homology and Lagrangian cobordisms
Резюме: We provide a partial answer to a question of Ekholm, Honda, and Kalman about the relationship between Khovanov homology and decomposable Lagrangian cobordisms. We also utilize previously defined filtered invariants to give a family of obstructions to decomposable Lagrangian cobordisms from Khovanov homology. Joint with Gage Martin and Zachary Winkeler.

За допълнителна информация:
https://icms.bg/khovanov-homology-and-lagrangian-cobordisms-icms-seminar-talk-by-ina-petkova/
https://icms.bg/category/icms-seminar/

Съвместен семинар на МЦМН и секция АГТ
2026-06-02 13:00 - 14:30
Date and time: Tuesday, June 2-nd, 2026, 13:00, room 403 IMI-BAS
Lecturer: Bogdan Djordjevic, (Serbian Academy of Arts and Sciences, visitor at ICMS, IMI-BAS)
Title: Application of the Laplace transform for evaluating sums of hyperharmonic-like series in Banach algebras and modules
Abstract: In this talk it will be shown how the Laplace transform (in respective Banach spaces) can be utilized for evaluating sums of Banach-space-valued series. We demonstrate the technique on various abstract generalizations of the numerical hyperharmonic series, including noncommutative setting and non-invertible setting. As an application, we obtain new necessary consistency condition for the Sylvester equation ()ax-xb=c[latex].

Семинар на МЦМН
2026-06-09 13:00 - 14:30
Дата и място: вторник, 9 юни 2026 г., 13:00, зала 403, ИМИ-БАН.
Лектор: Azur Đonlagić (Université Paris-Saclay
Заглавие: Brauer-Manin Obstructions for Homogeneous Spaces
Резюме: In this talk, we introduce Brauer-Manin obstructions to the Hasse principle and to weak/strong approximation of adelic points on varieties over a global field. We also define variants of these obstructions well-suited for the study of rational points on homogeneous spaces of affine algebraic groups.
We then state the main questions considered in this theory and give an account of some developments, including the speaker’s recent work. Finally, we present briefly the main tools and ideas used in the theory, such as arithmetic duality theorems, highlighting the difficulties which appear in positive characteristic.

За допълнителна информация:
https://icms.bg/brauer-manin-obstructions-for-homogeneous-spaces/
https://icms.bg/category/icms-seminar/
