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Weekly research seminar
Organizers
- prof. dr hab. Rafał Latała
Information
Thursdays, 12:15 p.m. , room: 3160Home page
http://lists.mimuw.edu.pl/listinfo/sem-rpList of talks
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Dec. 4, 2025, 12:15 p.m.
Zong Shang (Institut Polytechnique de Paris,)
Benign Overfitting Property of the Minimum ell_q-norm Interpolant Estimator in Regression and Classification Problems (Benign Overfitting Property of the Minimum ell_q-norm Interpolant Estimator in Regression and Classification Problems)
In this talk, I will establish high-probability non-asymptotic upper bounds for the population excess risk of minimum \ell_q-norm interpolating estimators in linear regression for all q\geq 1, and minimum \ell_2-norm interpolating classifiers in linear classification. …
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Nov. 27, 2025, 12:15 p.m.
Witold Bednorz (University of Warsaw)
Some remarks on GSW algorithm (Some remarks on GSW algorithm)
We present an improvement of the GSW martingale method. This has some implications for the Komlos conjecture.
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Nov. 20, 2025, 12:15 p.m.
Maciej Wiśniewolski (Uniwersytet Warszawski)
On exponential functionals of isotropic Gaussian fields and related hypergeometric equations (On exponential functionals of isotropic Gaussian fields and related hypergeometric equations)
I will discuss a class of exponential integral functionals of isotropic Gaussian fields on the unit interval whose expectations satisfy a specific second-order ordinary differential equation. In a certain sense, this equation can be reduced …
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Nov. 6, 2025, 12:15 p.m.
Anna Talarczyk-Noble (Uniwersytet Warszawski)
A generalized central limit theorem for critical marked Hawkes processes. (A generalized central limit theorem for critical marked Hawkes processes.)
We study marked Hawkes processes in which occurrence of an event increases the intensity of future events by a certain base intensity function multiplied by an independent mark. We are particularly interested in the case …
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Oct. 30, 2025, 12:15 p.m.
Alexandros Eskenazis (Sorbonne Université)
On metric formulations of Kwapień's theorem (On metric formulations of Kwapień's theorem)
We will construct counterexamples to previously conjectured metric formulations of Kwapień's theorem from Banach space theory. The key new ingredient in our construction is a novel rigidity theorem for metric transforms of nonpositively curved Alexandrov …
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Oct. 16, 2025, 12:15 p.m.
Radosław Adamczak (University of Warsaw)
Concentration of measure for nonlinear random matrices (Concentration of measure for nonlinear random matrices)
I will present concentration inequalities for certain models of random matrices related to neural networks. I will discuss their optimality and dependence on the choice of activation functions and the distribution of weights. Next, I …
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Oct. 9, 2025, 12:15 p.m.
Adam Osękowski (University of Warsaw)
Weighted weak-type inequalities for martingale transforms and square functions (Ważone nierówności słabego typu dla transformat martyngałowych i funkcji kwadratowych)
Consider the context of dyadic martingales and two types of operators: martingale transforms and square functions. When 1 <= p < oo, such operators satisfy weighted weak-type (p,p) estimates, under the assumption that the weight …
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June 5, 2025, 12:15 p.m.
Witold Bednorz (Uniwersytet Warszawski)
Concentration properties of the truncated variation functional of fractional Brownian motions of any Hurst index (Concentration properties of the truncated variation functional of fractional Brownian motions of any Hurst index)
We obtain bounds for probabilities of deviations of the truncated variation functional of fractional Brownian motions of any Hurst index H in (0; 1) from their expected values. Obtained bounds are optimal for large values …
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May 22, 2025, 12:15 p.m.
Lorenzo Sadun (University of Texas at Austin)
Random graphs with near-extreme triangle counts
We consider large dense random graphs with constraints on the densities $(e,t)$ of edges and triangles. For values of $(e,t)$ near the boundary of the ``Razborov triangle'', we show that all but an exponentially small …
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May 15, 2025, 12:15 p.m.
Ioannis Kavvadias (University of Warsaw)
Follmer process: Functional Inequalities and Concentration for Convex functions (Follmer process: Functional Inequalities and Concentration for Convex functions)
We will prove a representation formula for Gaussian relative entropy given by J. Lehec and use it to prove several functional inequalities. Moreover, we give a representation formula for the log-Laplace transform via stochastic processes …
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April 10, 2025, 12:15 p.m.
Adam Osękowski (Uniwersytet Warszawski)
Inequalities for a nonnegative submartingale and the nondecreasing component coming from the Doob-Meyer decomposition (Nierówności dla nieujemnego podmartyngału i składowej niemalejącej z rozkładu Dooba-Meyera)
An arbitrary nonnegative submartingale can be expressed as the sum M+A, where M is a local martingale starting from zero and A is a non-decreasing process. During the talk we will discuss the sharp comparison …
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April 3, 2025, 12:15 p.m.
Rafał Latała (University of Warsaw)
Upper bound on the injective norm of sums of Gaussian random tensors via the PAC Bayesian lemma (after I.Aden-Ali) (Upper bound on the injective norm of sums of Gaussian random tensors via the PAC Bayesian lemma (after I.Aden-Ali))
We will discuss a recent result of Ishaq Aden-Ali (On the Injective Norm of Sums of Random Tensors and the Moments of Gaussian Chaoses, arXiv:2503.10580) and show how the PAC-Bayesian lemma (a simple consequence of …
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March 27, 2025, 12:15 p.m.
Maud Szusterman (Uniwersytet Warszawski)
Revisiting Banaszczyk's 5K-theorem (Revisiting Banaszczyk's 5K-theorem)
Banaszczyk's 5K-theorem is an important result in combinatorics. It states that in any dimension n, given any finite sequences of vectors u_1, ... , u_t taken from the unit ball B_2^n , and given any …
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March 20, 2025, 12:15 p.m.
Jacek Jakimiuk
Stability of Khintchine inequalities with optimal constants (Stability of Khintchine inequalities with optimal constants)
We give a strengthening of the classical Khintchine inequality between the second and the $p$-th moment for $p \ge 3$ with optimal constant by adding a deficit depending on the vector of coefficients of the …
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March 6, 2025, 12:15 p.m.
Eli Putterman (Tel Aviv University)
Small-ball probabilities for mean widths of random polytopes (Small-ball probabilities for mean widths of random polytopes)
The classical theory of random polytopes addresses questions such as computing the expectation or variance of geometric parameters associated to a random polytope (e.g., volume, number of facets, or mean width); more recent theory also …
