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Mon, 27. May at 13:00
Rudower Chaussee ...
Continua of equilibrium states in globally coupled ensembles
Mon, 27. May at 14:00
WIAS ESH and onli...
Robust Multilevel Training of Artificial Neural Networks
Abstract. In this talk, we will introduce a multilevel optimizier for training of an artificial neural network. We are particularly interested in nerual networks to learn the hidden physical law or nonlinear mapping from the given data using algebraic multigrid strategies. And we would like to give some further insight into the potential of multilevel optimization methods in the end.
Tue, 28. May at 13:00
Backpropagation and Nonsmooth Optimization for Machine Learning
Abstract. Backpropagation is the major workhorse for many machine learning algorithms. In this presentation, we will examine the theory behind backpropagation as provided by the technique of algorithmic differentiation. Subsequently, we will discuss how this classic derivative information can be used for nonsmooth optimization. Examples from reail will illustrate the application of the proposed nonsmooth optimization algorithm.
Tue, 28. May at 13:15
Room 3.006, Rudow...
p-adic integration on Artin stacks
Abstract. After giving an introduction to the technique of p-adic integration, I will explain how this technique can be extended to Artin stacks, and give an application to BPS invariants. This is joint work with M. Groechenig and D. Wyss.
Wed, 29. May at 10:00
WIAS HVP5-7 R411 ...
Wed, 29. May at 10:00
WIAS Erhard-Schmi...
A functional-data perspective in spatial data analysis
Abstract. More and more spatiotemporal data nowadays can be viewed as functional data. The first part of the talk focuses on the Argo data, which is a modern oceanography dataset that provides unprecedented global coverage of temperature and salinity measurements in the upper 2,000 meters of depth of the ocean. I will discuss a functional kriging approach to predict temperature and salinity as a smooth function of depth, as well as a co-kriging approach of predicting oxygen concentration based on temperature and salinity data. In the second part of the talk, I will give an overview on some related topics, including spectral density estimation and variable selection for functional data.
Wed, 29. May at 13:00
default
Wed, 29. May at 13:15
Room 3.006, Rudow...
Wed, 29. May at 14:15
WIAS, Erhard-Schm...
Thu, 30. May
Thu, 30. May at 15:00
Relationships between the geometry of graph polytopes and graph structure
Abstract. The symmetric edge polytope is a lattice polytope associated to a graph, that is actively investigated both because of its beautiful geometry, and because of its connections to the Kuramoto synchronization model of physics. One can also investigate ‚Äěnon-symmetric‚ÄĚ edge polytopes, that are assigned to directed graphs instead of undirected ones. Moreover, one can even generalize them to regular (oriented) matroids. For these more general polytopes, many interesting geometric phenomena uncover themselves that are hidden for symmetric edge polytopes. We would like to demonstrate that the geometric properties of (graph and matroid) edge polytopes are connected to deep graph/matroid-theoretic properties. In particular, we show that the co-degree of an edge polytope is equal to the minimal cardinality of a dijoin. Other notions of combinatorial optimization also turn up naturally with respect to edge polytopes. In particular, for an Eulerian directed graph, complements of arborescences rooted at a given vertex give a (unimodular) triangulation of the edge polytope of the cographic matroid. This gives an alternative, geometric proof for the fact that an Eulerian digraph has the same number of arborescences for any choice of root vertex. I will also mention open problems. Based on joint work with Tam√°s K√°lm√°n.
Thu, 30. May at 16:15
TU Berlin, Instit...
General Equilibrium with Unhedgeable Fundamentals and Heterogeneous Agents
Abstract. We examine the implications of unhedgeable fundamental risk, combined with agents' heterogeneous preferences and wealth allocations, on dynamic asset pricing and portfolio choice. We solve in closed form a continuous-time general equilibrium model in which unhedgeable fundamental risk affects aggregate consumption dynamics, rendering the market incomplete. Several long-lived agents with heterogeneous risk-aversion and time-preference make consumption and investment decisions, trading risky assets and borrowing from and lending to each other. We find that a representative agent does not exist. Agents trade assets dynamically. Their consumption rates depend on the history of unhedgeable shocks. Consumption volatility is higher for agents with preferences and wealth allocations deviating more from the average. Unhedgeable risk reduces the equilibrium interest rate only through agents' heterogeneity and proportionally to the cross-sectional variance of agents' preferences and allocations.
Thu, 30. May at 17:00
TU Berlin, Instit...
Solving probability measure uncertainty by nonlinear expectations
Abstract. In 1921, economist Frank Knight published his famous 'UncertaintyÔľĆRisk and Profit' in which his challenging is still largely open.In this talk we explain why nonlinear expectation theory provides a powerful and fundamentally important mathematical tool to this century problem.
Fri, 31. May at 14:15
@TU (EW 201)
Beyond hyperbolic geometry
Tue, 04. Jun at 13:15
3.007 John von Ne...
Wed, 05. Jun at 10:00
WIAS Erhard-Schmi...
Optimal transport and gradient flows for optimization and machine learning: Wasserstein, Hellinger, Fisher-Rao, and reproducing kernels
Wed, 05. Jun at 11:30
online
Data-Adaptive Discretization of Inverse Problems
Wed, 05. Jun at 16:30
EN 058
Wed, 05. Jun at 16:30
EN 058
Thu, 06. Jun at 18:00
FU Berlin,  Insti...
 Zauberhafte Mathematik
Abstract. ¬†Wenn Kunstst√ľcke von Zauberern das Publikum beeindrucken, kann das verschiedene Ursachen haben. Es kann dann um Fingerfertigkeit gehen, oder um Ablenkung, den Einsatz mehr oder weniger komplizierter Apparaturen bis hin zu aufw√§ndigen elektronischen Schaltungen usw. Man kann sich aber auch Tatsachen aus verschiedenen Wissenschaftsgebieten zunutze machen: Physik, Chemie und nat√ľrlich auch Mathematik. In dem Vortrag soll gezeigt werden, wie man verschiedene Aspekte unseres Faches f√ľr die Zauberei nutzen kann. Eher klassisch (und meiner Meinung nach ein bisschen langweilig) ist der Einsatz elementarer Algebra: "Denk Dir eine Zahl ..." Darum wird es nicht gehen. Vielmehr werden wir Beispiele aus Kombinatorik, Gruppentheorie, Stochastik und Zahlentheorie kennenlernen. Das Niveau reicht von "leicht verst√§ndlich" bis "ein bisschen anspruchsvoll". F√ľr Bachelorstudierende sollte es keine Probleme geben. Es empfiehlt sich, etwas zum Schreiben und ein Kartenspiel dabei zu haben. Dann kann man einige der Kunstst√ľcke gleich ausprobieren.
Tue, 11. Jun at 13:15
Room 3.006, Rudow...
Wed, 12. Jun at 10:00
WIAS Erhard-Schmi...
Wed, 12. Jun at 16:30
EN 058
Thu, 13. Jun
Thu, 13. Jun
Thu, 13. Jun at 15:15
Rudower Chaussee ...
Thu, 13. Jun at 16:00
TU Berlin, Instit...
Stochastic Fredholm equations: a passe-partout for propagator models with cross-impact, constraints and mean-field interactions
Abstract. We will provide explicit solutions to certain systems linear stochastic Fredholm equations. We will then show the versatility of these equations for solving various optimal trading problems with transient impact including: (i) cross-impact (multiple assets), (ii) constraints on the inventory and trading speeds, and (iii) N-player game and mean-field interactions (multiple traders). Based on joint works with Nathan De Carvalho, Eyal Neuman, Huyên Pham, Sturmius Tuschmann, and Moritz Voss.
Fri, 14. Jun at 14:15
@TU (EW 201)
Wed, 19. Jun at 11:30
online
A Soft-Correspondence Approach to Shape Analysis
Wed, 19. Jun at 13:15
3.007 John von Ne...
Wed, 19. Jun at 16:30
EN 058
Thu, 20. Jun at 00:00
Tue, 25. Jun at 13:15
Room 3.006, Rudow...
Wed, 26. Jun at 10:00
R. 3.13 im HVP 11a
Wed, 26. Jun at 16:30
EN 058
What is the tropicalization of a matrix?
Abstract. Tropicalization is a process that associates to an algebro-geometric object a piecewise linear polyhedral shadow that captures its essential combinatorial structure. In this talk, I will give an overview of the numerous ways on how to extract tropical information from a matrix over a non-Archimedean field. Each perspective will give rise to inherently quite different phenomena. Central instances of this rich panorama include the tropical geometry of vector bundles, logarithmic concavity results for valuated (bi-)matroids (using techniques from combinatorial Hodge theory), and the geometry of affine buildings.This talk draws from joint work with Andreas Gross and Dmitry Zakharov; Andreas Gross, Inder Kaur, and Annette Werner; Felix R√∂hrle; Jeff Giansiracusa, Felipe Rincon, and Victoria Schleis; Luca Battistella, Kevin K√ľhn, Arne Kuhrs, and Alejandro Vargas; as well as with Desmond Coles.
Thu, 27. Jun at 15:00
Thu, 27. Jun at 16:15
TU Berlin, Instit...
Thu, 27. Jun at 17:00
TU Berlin, Instit...
Fri, 28. Jun at 14:15
@ZIB
Tue, 02. Jul at 13:15
Room 3.006, Rudow...
Wed, 03. Jul at 10:00
WIAS Erhard-Schmi...
Wed, 03. Jul at 11:30
online
Wasserstein Gradient Flows for Generalised Transport in Bayesian Inversion
Wed, 03. Jul at 14:15
WIAS, Erhard-Schm...
Measure-valued solutions for non-associative finite plasticity
Abstract
Thu, 04. Jul at 15:00
Fri, 05. Jul at 14:15
@HU (ESZ)
Richard von Mises Lecture
Wed, 10. Jul at 10:00
WIAS Erhard-Schmi...
Wed, 10. Jul at 11:30
online
Does gender still matter? Perspectives of scientists in leadership position and early career researchers on academic careers in mathematics.
Wed, 10. Jul at 14:15
WIAS, Erhard-Schm...
Variational Gaussian approximation for quantum dynamics
Abstract
Thu, 11. Jul at 15:00
Thu, 11. Jul at 16:00
TU Berlin, Instit...
Thu, 11. Jul at 17:00
TU Berlin, Instit...
Tue, 16. Jul at 13:15
Room 3.006, Rudow...
Wed, 17. Jul at 11:30
online
Likelihood Geometry of Max-Linear Bayesian Networks
Thu, 18. Jul at 15:00
Wed, 24. Jul at 14:15
WIAS, Erhard-Schm...