Ran
Tao
MPI MiS Leipzig
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05. February
Today
János
Nitschke
HU Berlin
Ana
Damnjanovic
Finite volume methods for regularized Dean-Kawasaki equations
Tom
Bdolach
HU Berlin
Economic MPC with periodic stabilizing terminal constraints for a generalized Nash equilibrium problem
10. February
Tue W06
Andrea
Brini
Sheffield University
On the conifold gap for the local projective plane
Abstract.
The conifold gap conjecture asserts that the polar part of the Gromov-Witten potential of a Calabi-Yau threefold near its conifold locus has a universal expression described by the logarithm of the Barnes G-function. In this talk I will describe a proof of the conifold gap conjecture for the local projective plane, whereby the higher genus conifold Gromov-Witten generating series of local P^2 are related to the thermodynamics of a certain statistical mechanical ensemble of repulsive particles on the positive half-line. As a corollary, this establishes the all-genus mirror principle for local P^2 through the direct integration of the BCOV holomorphic anomaly equations.
11. February
Wed W06
Ho
Yun
EPFL
Linear Monge is All You Need
Abstract.
In this talk, we explore the geometry of the Bures-Wasserstein space for potentially degenerate Gaussian measures on a separable Hilbert space, based on our recent work with Yoav Zemel. A key feature of our approach is its simplicity: relying only on elementary arguments from linear operator theory, we are able to derive explicit results without resorting to Kantorovich duality or Otto's Calculus. We provide a complete characterisation of both the Monge and Kantorovich problems in this context, regardless of the degeneracy of their measures. Furthermore, we show a simple way to construct all possible Wasserstein geodesics connecting two Gaussian measures. Finally, we generalise our results to characterise Wasserstein barycenters of Gaussian measures, borrowing the idea of Procrustes distance from statistical shape analysis.
BĂ©atrice
Matteo
University of Geneva
Kernel ridge regression for spherical responses
Abstract.
The aim is to propose a novel nonlinear regression framework for responses taking values on a hypersphere. Rather than performing tangent space regression, where all the sphere responses are lifted to a single tangent space on which the regression is performed, we estimate conditional Fréchet means by minimizing squared distances on the nonlinear manifold. Yet, the tangent space serves as a linear predictor space where the regression function takes values. The framework integrates Riemannian geometry techniques with functional data analysis by modelling the regression function using methods from vector-valued reproducing kernel Hilbert space theory. This formulation enables the reduction of the infinite-dimensional estimation problem to a finite-dimensional one via a representer theorem and leads to an estimation algorithm by means of Riemannian gradient descent. Explicit checkable conditions on the data that ensure the existence and uniqueness of the minimizing estimator are given.
Elias
Zimmermann
Universität Leipzig
Quantitative mixing properties for Gibbs fields on bounded degree graphs
Abstract.
Mixing properties are an important object of study within the theory of Gibbs measures. In this talk I will focus on two quantitative mixing properties: exponential $\phi$-mixing (also called weak mixing) and exponential $\psi$-mixing (also called ratio weak mixing). These mixing conditions are well studied for Gibbs fields on square lattices. For instance, the unique Gibbs state of the Ising model above the critical temperature exhibits both types of mixing. In this talk we shall consider random fields on arbitrary graphs with bounded degree. While exponential $\phi$-mixing is known to hold whenever Dobrushin's uniqueness condition is satisfied, exponential $\psi$-mixing has been studied very little in this general setting. The main result I'm going to present shows that for Markovian random fields $\phi$-mixing with sufficiently high exponential decay rate implies $\psi$-mixing with slower, but still exponential decay rate. This generalizes a result of Alexander for square lattices and allows to formulate a general criterion for exponential $\psi$-mixing of Gibbs measures in terms of the corresponding Dobrushin constant. I will illustrate how this criterion applies to Ising and Potts models on regular trees.
Andrea
Poiatti
Universität Wien
A Navier--Stokes/Mullins--Sekerka system with different densities: weak solutions
Abstract
Tony
Lelievre
CERMICS
Vitalii
Konarovskyi
U Hamburg
12. February
Thu W06
Alexander
Schill
Andre
Zepernick
Rudi
Pendavingh
TU Eindhoven
Counting cells of the Dressian
Abstract.
A valuation of a matroid M is a map v that assigns a real value v(B) to each basis B of M, such that a quantitative version of the symmetric base exchange axiom holds: v is a valuation of M if and only if (V) for all bases B, B’ of M an all e in B\B’, there is an f in B'\B so that v(B) + v(B’) >= v(B-e+f) + v(B'+e-f). The Dressian is the collection of all valuations of M: Dr(M):= { v : v a valuation of M }. Dr(M) is a polyhedral complex in R^{bases of M}. In previous joint work with Guus Bollen and Jan Draisma, we found that each algebraic representation of M over a finite field gives rise to a valuation of M. In some cases this fact could be used to rule out that M has an algebraic representation. Such arguments would always involve an enumeration of the cells of Dr(M). This promted the question how the cells of Dr(M) are best enumerated and more broadly, what properties of M limit their number and variation. In this talk, I describe a method for bounding the number of cells of the Dressian, inspired by entropy counting and the contained method.
Guido
Gazzani
University of Verona
Â
cancelled
Beatrice
Ongarato
Technische Universität Dresden
14. February
Sat W06
Mikhail
Gorsky
Jean Monnet University
18. February
Wed W07
Marta
Dai Pra
HU Berlin
Diego A.
Robayo Bargans
RPTU
25. February
Wed W08
Marta
Dai Pra
HU Berlin
04. March
Wed W09
Felix
Röhrle
University of TĂĽbingen
15. April
Wed W15
Pierluigi
Colli
UniversitĂ Pavia, Italy
16. April
Thu W15
José Antonio
Carrillo
University of Oxford, United Kingdom
21. April
Tue W16
Pierrick
Bousseau
Oxford University
Corentin
Bodart
Oxford
28. April
Tue W17
Simon
Andre
Paris
29. April
Wed W17
Laura
Ciobanu
TU Berlin
05. May
Tue W18
Damien
Simon
Sorbonne Universite
20. May
Wed W20
Riccarda
Rossi
University of Brescia, Italy
07. July
Tue W27
Alexander
Alexandrov
IBS Pohang
14. July
Tue W28
Alexander
Alexandrov
IBS Pohang
17. December
Thu W50
Lars
Kastner
TU Berlin
Drawing algebraic curves in OSCAR