семинар Алгебра и логика

На 10 февруари 2023 г. (петък) от 13:00 часа ще се проведе дистанционно заседание на семинара по „Алгебра и логика”. Доклад на тема: A New Approach to the Characteristic Polynomial of a Random Unitary Matrix ще изнесе Yacine Barhoumi-Andréani (Ruhr-Universität Bochum, Germany). Абстракт. The characteristic polynomial of a random (Haar-distributed) unitary matrix is considered as an interesting toy model for the probabilistic study of the Riemann Zeta function. We will recall the history of the topic starting with the Montgommery-Dyson correspondance, the Keating-Snaith moments conjecture and some recent developments on other functionals. We will then give a conceptual comparison of some of the techniques used in the field and a zoo of results one can achieve, with a particular focus on a recent technique [...]

На 17 февруари 2023 г. (петък) от 13:00 часа ще се проведе дистанционно заседание на семинара по „Алгебра и логика”. Доклад на тема: Invariant theory for reductive subgroups of reductive groups ще изнесе Валдемар Цанов (ИМИ-БАН). Абстракт. Let H ⸦ G be an embedding of connected complex reductive linear algebraic groups. A classical question with several important interpretations is: which irreducible G-modules contain nonzero H-invariant vectors? An approach based on the Geometric Invariant Theory of Hilbert-Mumford was developed in works of Heckman, Berenstein-Sjamaar, Belkale-Kumar and Ressayre, culminating in a description of the generalized Littlewood-Richadson cone - the convex hull of set of the highest weights of the G-modules containing H-invariants. The discrepancy between the convex hull and the actual set of weights presents the [...]

На 24 февруари 2023 г. (петък) от 13:00 часа ще се проведе дистанционно заседание на семинара по „Алгебра и логика”. Доклад на тема: Real Hamiltonian forms of affine Toda field theories: spectral aspects ще изнесе Владимир Герджиков (съвместна работа с Г. Г. Граховски и А. А. Стефанов). Абстракт. The talk is devoted to real Hamiltonian forms of 2-dimensional Toda field theories related to exceptional simple Lie algebras, and to the spectral theory of the associated Lax operators. Real Hamiltonian forms are a special type of reductions of Hamiltonian systems, similar to real forms of semisimple Lie algebras. The real Hamiltonian forms of affine Toda field theories related to exceptional complex untwisted affine Kac - Moody algebras are studied. Along with the associated Lax representations, [...]