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Konferenzen und Workshops

Forschungsseminar über diskrete Spektraltheorie

26.02. bis 26.02.2020, 12:30  –  Campus Golm, Haus 9, Raum 2.09.2.22
Forschungsseminar Diskrete Spektraltheorie

Harmonic Functions on Graphs with Group Actions

Matti Richter

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22.01. bis 22.01.2020, 12:30 Uhr  –  Campus Golm, Haus 9, Raum 2.09.0.14
Forschungsseminar Diskrete Spektraltheorie

Quantitative estimates between the spectra of Schrödinger operators

Dr. Siegfried Beckus (Universität Potsdam)

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11.12. bis 11.12.2019, 12:30 Uhr  –  Campus Golm, Haus 9, Raum 2.09.2.22
Forschungsseminar Diskrete Spektraltheorie

Two trace formulae for Hermitian matrices

Uzy Smilansky (Weizmann Institute of Science)

Trace formulae are one of the most important tools in a large number of fields ranging from quantum chaos via spectral geometry, graphs and number theory. Here, I shall present two rather... 

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11.12.2019, 13:45 Uhr  –  Campus Golm, Haus 9, Raum 2.09.2.22
Forschungsseminar Diskrete Spektraltheorie

Bonnet-Myers theorem for Kato-type Ricci curvature conditions

Dr. Christian Rose (MPI Leipzig)

The Kato condition on the negative part of the Ricci curvature turned out to be an appropriate generalization of Lp- curvature conditions that can be used to investigate geometric and topological... 

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27.11. bis 27.11.2019, 12:30 Uhr  –  Campus Golm, Haus 9, Raum 2.09.0.14
Forschungsseminar Diskrete Spektraltheorie

On effective impedance of networks

Anna Muranova (Bielefeld University)

Abstract

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20.11. bis 20.11.2019, 12:30 Uhr  –  Campus Golm, Haus 9, Raum 2.09.0.14
Forschungsseminar Diskrete Spektraltheorie

On Courant's nodal domain property for linear combinations of eigenfunctions (after P. B\'erard, P. Charron and B. Helffer)

Bernard Helffer (University of Paris-Sud)

Abstract: We revisit  Courant's nodal domain property for linear combinations of eigenfunctions. This property was proven by Sturm (1836) in the case of dimension 1.  Although stated as true for the... 

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13.11. bis 13.11.2019, 12:30 Uhr  –  Campus Golm, Haus 9, Raum 2.09.0.14
Forschungsseminar Diskrete Spektraltheorie

Approximating the integrated density of states of random Schrödinger operators - results from empirical process theory

Max Kämper (TU Dortmund)

Random Schrödinger operators are a model for metals with random impurities and this talk will present them for the special case of the Anderson operator on a lattice. We will introduce the integrated... 

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30.10. bis 30.10.2019, 12:30 Uhr  –  Campus Golm, Haus 9, Raum 2.09.0.14
Forschungsseminar Diskrete Spektraltheorie

Infinite Quantum Graphs

Noema Nicolussi (University of Vienna)

Abstract

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16.10.2019, 12:30  –  Campus Golm, Haus 9, Raum 2.09.0.14
Forschungsseminar Diskrete Spektraltheorie

Nodal statistics of quantum graph eigenfunctions

Prof. Dr. Ram Band (Israel Institute of Technology - Technion)

We discuss the number of zeros of Laplacian eigenfunctions on a metric (quantum) graph.
The n-th eigenfunction has at least n-1 zeros and at most n-1+\beta zeros, where \beta is the number of graph... 

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27.02.2019, 13:00 Uhr  –  Campus Golm, Haus 9, Raum 2.09.1.10
Forschungsseminar Diskrete Spektraltheorie

Interpolation Theory for Singular Integrals on Spaces of Homogeneous Type

Philipp Bartmann

We will discuss aspects of classical interpolation theory including properties of the Hardy–Littlewood maximal function and Marcinkiewicz’s interpolation theorem. Further, we will establish the... 

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20.02.2019, 16:00 Uhr  –  Campus Golm, Haus 9, Raum 2.09.1.10
Forschungsseminar Diskrete Spektraltheorie

Globale topologische Poincaré Ungleichung auf Graphen

Jonas Grünberg

 

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30.01.2019, 16:30 Uhr  –  Campus Golm, Haus 9, Raum 2.09.1.10
Forschungsseminar Diskrete Spektraltheorie

Parabolic Harnack Inequality, Gaussian Estimates and Geometric Properties on Graphs

Christian Scholz

Consider a countable set and a weighted, uniformly locally finite graph. In his paper "Parabolic Harnack inequality and estimates of Markov chains on graphs", Delmotte proves that parabolic Harnack... 

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09.01.2019, 16:30 Uhr  –  Campus Golm, Haus 9, Raum 2.09.1.10
Forschungsseminar Diskrete Spektraltheorie

Neumann problems on graphs

Michael Schwarz

Abstract

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19.12.2018, 16:30 Uhr  –  Campus Golm, Haus 9, Raum 2.09.1.10
Forschungsseminar Diskrete Spektraltheorie

Spectral asymptotics of Robin Laplacians on polygonal domains

Magda Khalile (Leibniz Universität Hannover)

Abstract

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05.12.2018, 16:15 Uhr  –  Campus Golm, Haus 9, Raum
Forschungsseminar Diskrete Spektraltheorie

Inference of Phylogenetic Trees from Homology-Relations

Marc Hellmuth (Universität Greifswald)

Phylogenomics aims at finding plausible hypothesis about the evolutionary history of gene or species based on genomic sequence information. Genes are passed from generation to generation to the... 

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28.11.2018, 16:30 Uhr  –  Campus Golm, Haus 9, Raum 2.09.1.10
Forschungsseminar Diskrete Spektraltheorie

A Riesz' Decomposition Theorem for Schrödinger Operators On Graphs

Florian Fischer (Universität Potsdam)

In the classical potential theory on Euclidean space and in the potential theory of transient Markov chains a unique decomposition of superharmonic functions in a harmonic and a potential part is... 

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14.11.2018, 16:15 Uhr  –  Campus Golm, Haus 9, Raum 2.09.1.10
Forschungsseminar Diskrete Spektraltheorie

Kato-type curvature conditions and the Cheeger constant

Christian Rose (Technische Universität Chemnitz)

We show that if the negative part of the Ricci curvature of a compact manifold is in the Kato-class, the Cheeger constant of the manifold can be bounded below by a positive constant. This is obtained... 

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07.11.2018, 16:15 Uhr  –  Campus Golm, Haus 9, Raum 2.09.1.10
Forschungsseminar Diskrete Spektraltheorie

Shnol type theorem for the Agmon ground state - the discrete setting

Siegfried Beckus (Universität Potsdam)

The celebrated Shnol theorem asserts that every polynomially bounded generalized eigenfunction for a given energy E associated with a Schrödinger operator H implies that E is in the L2-spectrum of H.... 

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19.01.2017, 10:30 Uhr  –  Campus Golm, Haus 9, Raum 1.10
Forschungsseminar Diskrete Spektraltheorie

A transport metric for non-local Dirichlet forms and gradient flows of the entropy

Melchior Wirth

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12.01.2017, 10:30 Uhr  –  Campus Golm, Haus 9, Raum 1.10
Forschungsseminar Diskrete Spektraltheorie

First order calculus for Dirichlet forms and some applications to PDE

Michael Hinz (Bielefeld)

In this talk we review the definitions of items of vector calculus based on Dirichlet forms and mention connections to graph Laplacians and to non-local and local operators on metric measure spaces.... 

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05.01.2017, 10:30 Uhr  –  Campus Golm, Haus 9, Raum 1.10
Forschungsseminar Diskrete Spektraltheorie

Audible and inaudible curvature invariants

Dorothee Schüth (HU Berlin)

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08.12.2016, 10:30 Uhr  –  Campus Golm, Haus 9, Raum 1.10
Forschungsseminar Diskrete Spektraltheorie

Discrete Ricci curvature via geodesic convexity of the entropy

Jan Maas (IST Austria)

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01.12.2016, 10:15 Uhr  –  Campus Golm, Haus 9, Raum 1.10
Forschungsseminar Diskrete Spektraltheorie

Courant's nodal domain theorem for regular Dirichlet forms

Michael Schwarz

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24.11.2016, 10:30 Uhr  –  Campus Golm, Haus 9, Raum 1.10
Forschungsseminar Diskrete Spektraltheorie

Rigidity properties of the hypercube via Bakry Emery curvature

Florentin Münch

We give rigidity results for discrete Bonnet-Myers diameter bound and Lichnerowicz eigenvalue estimate. Both inequalities are sharp if and only if the underlying graph is a hypercube.  The proofs use... 

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03.11.2016, 10:00 Uhr  –  Campus Golm, Haus 9, Raum 1.10
Forschungsseminar Diskrete Spektraltheorie

Exactness of Dynamical Systems and Convergence of Semigroups

Moritz Gerlach

This talk aims at completing the picture how exactness of dynamical systems is related to the asymptotic behavior of the Perron-Frobenius operator. In doing so, we give a mixing-like description of... 

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27.10.2016, 11:00 Uhr  –  Campus Golm, Haus 9, Raum 1.10
Forschungsseminar Diskrete Spektraltheorie

Nichtkommutative Quasikristalle

Felix Pogorzelski (Technion Haifa)

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19.07.2016, 12:30  –  Campus Golm, Haus 9, Raum 0.13
Forschungsseminar Diskrete Spektraltheorie

Essential selfadjointness and the l^2 Liouville property

Radoslaw Wojciechowski (CUNY)

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05.07.2016, 12:30  –  Campus Golm, Haus 9, Raum 0.13
Forschungsseminar Diskrete Spektraltheorie

Ricci curvature and eigenvalue estimate for the magnetic Laplacian on manifolds

Shiping Liu (Durham)

I will discuss a Buser type and a Lichnerowicz type eigenvalue estimates for the magnetic Laplacian on a closed Riemannian manifold. Those are motivated by our previous ... 

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23.06.2016, 10:30 Uhr  –  Campus Golm, Haus 5, Raum 1.04
Forschungsseminar Diskrete Spektraltheorie

On the spectrum of operator families on discrete groups over minimal dynamical systems

Christian Seifert (Hamburg Harburg)

We consider families of bounded linear operators on \ell_p-spaces of discrete groups, parametrized by a dynamical system. By using limit operator techniques, we show that all the operators from that... 

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16.06.2016, 14:15 Uhr  –  Campus Golm, Haus 14, Raum 0.38
Forschungsseminar Diskrete Spektraltheorie

Averaging principles: From a microscopic to a macroscopic point of view

Markus Kunze (Konstanz)

We consider diffusion problems in a domain which is further subdivided by semi-permeable membranes. Such problems frequently occur in applications in biology, for example when studying the... 

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07.06.2016, 12:15  –  Campus Golm, Haus 9, Raum 0.13
Forschungsseminar Diskrete Spektraltheorie

Seminar "Mengentheoretische Topologie": Der Satz von Tychonoff

Martin Schuhmacher

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31.05.2016, 12:30  –  Campus Golm, Haus 9, Raum 0.13
Forschungsseminar Diskrete Spektraltheorie

Complex line bundles over simplicial complexes

Felix Knöppel (TU Berlin)

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10.05.2016, 12:30  –  Campus Golm, Haus 9, Raum 0.13
Forschungsseminar Diskrete Spektraltheorie

Heat kernel estimates on measure spaces and the relative compactness of perturbations by potentials

Batu Güneysu (HU Berlin)

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03.05.2016, 12:30  –  Campus Golm, Haus 9, Raum 0.13
Forschungsseminar Diskrete Spektraltheorie

Agmon-Abschätzungen für Differenzen-Operatoren

Elke Rosenberger (Potsdam)

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26.04.2016, 12:30 Uhr  –  Campus Golm, Haus 9, Raum 0.13
Forschungsseminar Diskrete Spektraltheorie

Continuous variation of the spectrum: A characterization and a tool

Siegfried Beckus (University Jena)

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04.02.2016, 12:30 Uhr  –  Campus Golm, Haus 5, Raum 1.12
Forschungsseminar Diskrete Spektraltheorie

Integral Ricci curvature bounds and the Kato class on Riemannian manifolds

Christian Rose (TU Chemnitz)

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21.01.2016, 12:30 Uhr  –  Campus Golm, Haus 5, Raum 1.12
Forschungsseminar Diskrete Spektraltheorie

Asymptotic behaviour of the Hodge-Laplacian spectrum on graph-like manifolds

Michela Egidi (TU Chemnitz)

In this talk (joint work with O. Post) we consider a family of compact, oriented and connected n-dimensional manifolds constructed according to the ... 

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14.01.2016, 12:30 Uhr  –  Campus Golm, Haus 5, Raum 1.12
Forschungsseminar Diskrete Spektraltheorie

The spectrum of the graph p-Laplacian operator

Francesco Tudisco (Saarland University)

This introductory talk will focus on the eigenvalues and eigenfunctions of the graph p-Laplacian. We shall discuss two definitions of the eigenpairs that come as a natural generalization of the linear... 

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10.12.2015, 12:30 Uhr  –  Campus Golm, Haus 5, Raum 1.12
Forschungsseminar Diskrete Spektraltheorie

Eventual Positivity of Operator Semigroups

Jochen Glück (Universität Ulm)

Let T = (T(t)) be a C_0-semigroup on some function space or, more generally, on a Banach lattice E. The semigroup T is called positive if T(t)f \ge 0 for each 0 \le f \in E and for each t \geg 0.... 

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03.12.2015, 12:30 Uhr  –  Campus Golm, Haus 5, Raum 1.12
Forschungsseminar Diskrete Spektraltheorie

On the Liouville property of harmonic functions

Jun Masamune (Tohoku University)

When every harmonic function belonging to a space $E$ of functions is identically constant, we say that the $E$-Liouville property holds true. There are different types of Liouville property according... 

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26.11.2015, 12:30 Uhr  –  Campus Golm, Haus 5, Raum 1.12
Forschungsseminar Diskrete Spektraltheorie

News about entropy

Felix Pogorzelski (Technion Haifa)

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19.11.2015, 12:30 Uhr  –  Campus Golm, Haus 5, Raum 1.12
Forschungsseminar Diskrete Spektraltheorie

Energy Forms

Marcel Schmidt (University Jena)

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05.11.2015, 12:30 Uhr  –  Campus Golm, Haus 5, Raum 1.12
Forschungsseminar Diskrete Spektraltheorie

Dirichlet Forms on Canonically Compactifiable Graphs

Michael Schwarz (Potsdam)

We consider weighted graphs with an infinite set $X$ of vertices such that every function of finite energy is bounded. For each of these graphs there is a compact set $K$ containing $X$ as a dense... 

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29.10.2015, 12:30 Uhr  –  Campus Golm, Haus 5, Raum 1.12
Forschungsseminar Diskrete Spektraltheorie

Curvature and Diffusion on Graphs -- Non-linear Curvature Dimension Conditions vs. Li-Yau Inequality

Florentin Münch (Potsdam)

We introduce a new version of curvature dimension inequality. We use this to prove a logarithmic Li-Yau inequality on graphs. To formulate this inequality, we use a non-linear ariant of the calculus... 

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22.10.2015, 12:30 Uhr  –  Campus Golm, Haus 5, Raum 1.12
Forschungsseminar Diskrete Spektraltheorie

Spectral Convergence of Empirical Graph Laplacians

Moritz Gerlach (Potsdam)

Given a finite sequence of n samples drawn independently at random from a compact submanifold of the Euclidean space, we study the asymptotic behavior of Laplacians on the epsilon-neighborhood graph... 

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