Cotygodniowe seminarium badawcze.
2023-01-26, godz. 12:15, 3160
Rafał Latała (Uniwersytet Warszawski)
Spectral norm bounds for Rademacher matrices
We will discuss bounds for the mean spectral norm of unhomogenous Rademacher matrices. We will recall a general conjecture formulated together with Witold Światkowski and show that it is satisfied in few particular cases. ...
2023-01-12, godz. 12:15, 5060 (note the change of room)
Michał Kotowski (Uniwersytet Warszawski)
Large deviations for the interchange process on the interval and incompressible flows
In the talk I will explain how large deviations for the one-dimensional interchange process are related to incompressible Euler equations. I will sketch how to obtain matching large deviation lower and upper bounds for processes which are energy-minimizing (under certain additional regularity assump...
2022-12-15, godz. 12:15, 3160
Radosław Adamczak (Uniwersytet Warszawski)
Isoperimetric inequalities for certain star-shaped bodies
I will present isoperimetric type inequalities for star-shaped sets that interpolate between intersection bodies and dual Lp centroid bodies, two classes of convex bodies studied in geometry. This provides a bridge between two well-known inequalities: the Busemann intersection inequality and the Lut...
2022-11-10, godz. 12:15, 3160
Katarzyna Pietruska-Pałuba (Uniwersytet Warszawski)
Lp identities and inequalities related to certain Levy proceses
I will present recent results, concerned with generators and forms (acting on Lp) related to Levy processes. We establish the Hardy-Stein identity in Lp and related multivariate identities. If time permits, we will also present the optimal Hardy inequality for stable processes. All these results req...
2022-11-03, godz. 12:15, 3160
Rémy Poudevigne-Auboiron (University of Cambridge)
Macroscopic cycles for the interchange process on random regular graphs
The interchange process can be seen as a random walk on permutations of a graph: at rate 1, independently on every edge, we exchange the value on both endpoints of the edge. This model was introduced as a way to study the quantum Heisenberg model. For this model, progress had been made on some speci...
2022-10-27, godz. 12:15, 3160
Witold Bednorz (Uniwersytet Warszawski)
Theorem on selectors and its extensions
I will present the analytical proof of the selectors theorem (in June I presented a much more combinatorial proof by Park and Pham). With the analytic approach, the argument is much clearer and shorter with much better constants. Let me remind you that this solves a quite important problem about the...
2022-10-13, godz. 12:15, 3160
Marta Strzelecka (University of Warsaw)
Norms of structured random matrices
Let us consider the structured m x n Gaussian matrix G_A=(a_{ij}g_{ij}), where g_{ij}'s are independent standard Gaussian variables and A=(a_{ij}) is a deterministic matrix. The exact behaviour of the spectral norm of the structured Gaussian matrix is known due to the result of Latała, van Hand...
2022-10-06, godz. 12:15, 3260
Adam Osękowski (Uniwersytet Warszawski)
Three inequalities, one constant
The purpose of the talk will be to discuss the following three estimates: 1) Bliss' inequality for real functions on positive halfline; 2) Sobolev's inequality (the imbedding theorem); 3) Sawyer's inequality which characterizes the boundedness of fractional maximal operator on weighte...
2022-06-02, godz. 12:15, 3260
Michał Skrzypecki (Uniwersytet Warszawski)
Proces Wienera i analiza na trójkącie Sierpińskiego
Początkowo fraktale służyły matematykom jako kontrprzykłady. Krzywa Kocha jest przykładem zwartej krzywej nieskończonej długości, zbiór Cantora jest nieprzeliczalnym zbiorem doskonałym zerowej miary Lebesgue'a. Z czasem zaczęto odkrywać przykłady fraktali w przyrodzie. Chcemy...
2022-05-26, godz. 12:15, 3260
Rafał Latała (Uniwersytet Warszawski)
O ostatnich wynikach dotyczących hipotezy Bourgaina o istnieniu dużych przekrojów ciał wypukłych
Słynny otwarty problem, sformułowany przez Bourgaina (hyperplane conjecture), mówi, że każde ciało wypukłe objętości 1 ma n-1 wymiarowy przekrój o objętości ograniczonej z dołu przez stałą uniwersalną. Bourgain wykazał, że z dokładnością do logarytmu z wymiaru ciało...