LKS-Seminar
Prof. S. Friedl PhD / Prof. Dr. C. LöhIn this seminar we will cover various topics in topology and geometric group theory.
Date/Time
In WS 24/25: We will meet on Friday, 10:15--11:45 (M201). Please register in GRIPS if you are interested in participating in this seminar.Scheduled meetings/talks in WS 24/25
| Date | Topic | Speaker |
| October 18 | event of the Faculty of Mathematics: PhD defense of Guadalupe Castillo Solano (10:00--12:00, M 104) | |
| October 25 | no talk because of other events | |
| November 1 | no talk (holiday: reformation day +1) | |
| November 8 | Knotions of knot equivalence | Stefan Friedl |
| November 15 | Knotions of knot equivalence II | Stefan Friedl |
| November 22 | Complex tori (at 12:15! M 201) | Viktor Lohr |
| November 29 | Bounded orbit equivalence and a bit of algebra | Clara Löh |
| December 6 | Deeply slice knot detection via immersed curves | Chen Zhang (Bochum) |
| December 13 | The cotangent complex for Tambara functors | Melvin Weiß (U Bonn) |
| December 20 | The Burnside problem and small cancellation theory | Malena Wasmeier |
| January 10 | ||
| January 17 | tba | Aditya Prabhu |
| January 24 | Riemannscher Abbildungssatz | Maximilian Böhm |
| January 31 | tba | Shrimadhi Srikanth |
| February 7 | tba | Kevin Li |
Scheduled meetings/talks in SS 24
| Date | Topic | Speaker |
| April 26 | "The" cube category | Georg Thurner |
| May 3 | Tanushree Shah (Vienna) | |
| May 10 | Wachstumsreihen von Gruppen [in German] | Johannes Weiß |
| May 17 | The homeomorphism problem for 4-manifolds | Matthias Uschold |
| May 31 | Twisted Alexander polynomials of hyperbolic knots | Stefan Friedl |
| June 7 | Primality tests and factorisation methods | Sabine Kiefl |
| June 14 | Outside the topology box: Orbit equivalence | Clara Löh |
| June 21 | Profinite rigidity and amenability | Anna Cascioli |
| June 28 | Large homology spheres | Matthias Holzammer |
| July 5 | The hyperboloid model and reflection groups | Benjamin Takacs |
| July 12 | G-Theory of group rings | Malena Wasmeier |
| July 19 | Persistent cohomology and cup products | Daniel Zach |
Scheduled meetings/talks in WS 23/24
| Date | Topic | Speaker |
| October 20 | Das Alexanderpolynom von Satellitenknoten | Tobias Hirsch |
| October 27 | The Kirby Torus Trick for Surfaces | Max Schopf |
| November 3 | ... Fortsetzung | Max Schopf |
| November 10 | Growth rates in hyperbolic groups | Hannes Lohberger (online) |
| (zoom access data: see GRIPS page; M 201 will be open, but you will need to bring your own device) | ||
| November 17 | Persistent homology analysis of the evolution of SARS-CoV-2 | Alison Durst |
| November 24 | Borsuk--Ulam Theorem | Konstantin Priller |
| December 1 | Der Vierfarbensatz (in German) | Jan Käsbauer |
| December 8 | Tubular neighbourhoods | Stefan Friedl |
| December 15 | Conformal Dimension of the Boundary for Hyperbolic Coxeter Groups | Julia Heller (KIT) |
| January 12 | Bring your favourite conjecture! | everybody |
| January 19 | Bring your favourite conjecture!, Part II | everybody |
| January 26 | arXivoloy: bring your favourite arXiv preprint from 2023 or 2024! | everybody |
| February 2 | arXivoloy: bring your favourite arXiv preprint from 2023 or 2024! Part II | everybody |
| February 9 | De Rham cohomology | Weichen Xue |
Scheduled meetings/talks in SS 23
| Date | Topic | Speaker |
| April 21 | Implementing Pachner's Theorem with Lean | Garett Cunningham |
| April 28 | Gauss linking number | Stefan Friedl |
| May 5 | Singularities, fibered knots and cobordisms | Filip Misev |
| May 12 | Minimal volume with different tools | Ulrich Steindl |
| May 19 | A Monster's Expedition (through Puzzling Exhibitions); eine mathematische Analyse | Sebastian Freiberger |
| May 26 | The Fekete Lemma and more | Clara Löh |
| June 2 | H-Raum-Struktur auf Sphären und K-Theorie | Patrick Perras |
| June 9 | Selberg's lemma | Eider Gonzalo |
| June 16 | Bounded cohomology, quasi-morphisms, and cup-products | Franziska Hofmann |
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| June 30 | Spectra of manifolds and random walks | Tim Höpfner (Göttingen) |
| July 7 | Asymptotic cones of bi-invariant metrics on groups | Jarek Kedra (University of Aberdeen) |
| July 14 | Geometric von Neumann problems on non-amenability | Simon Stahl |
| July 14 |
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| July 21 | Der Satz von Peter und Weyl | Lisa Schambeck |
| July 25, 12:15, M 104 | tba | José Pedro Quintanilha |
Scheduled meetings/talks in WS 22/23
| Date | Topic | Speaker |
| October 21 | arXivology (bring your favourite arXiv preprint from 2022) | everybody |
| October 28 | Blanchfield pairings and Gordian distance | Stefan Friedl |
| November 4 | arXivology, continued (from Oct 21) | everybody |
| November 11 | Laws and freedom (of groups) | Clara Löh |
| November 18 | Simplicial volume of closed locally homogeneous Riemannian manifolds [zoom talk] | Peng Hui How (UChicago) |
| November 25 | Khovanov Homology and the \lambda-Invariant | Damian Iltgen |
| December 2 | Sigma-Invariants | José Pedro Quintanilha (U Bielefeld) |
| December 9 | How to make Heegaard diagrams nice | Ludovico Morellato |
| December 16 | Homology growth and cheap rebuilding of inner-amenable groups | Matthias Uschold |
| December 22(!), 14:15, M 201 | Meridional rank of Whitehead doubles | Ederson Dutra |
| January 13 | Pseudo-Anosov maps | Filip Misev |
| January 20 | Homology theories in cofibration categories | Divya Ghanshani |
| January 27 | Homology spheres | Elisabeth Kraus |
| February 3 | Multicurves of double tangles | Claudius Zibrowius |
| February 10 | A QI-invariant cop number | Margarete Diem |
Scheduled meetings/talks in SS 22
| Date | Topic | Speaker |
| April 29 | Projects/Reading/Plans: Show-and-tell | everybody |
| May 6 | Regular homotopy of curves | Stefan Friedl |
| May 13 | Surjunctive groups | Thomas Hilz |
| May 20 | The monodromy group of a positive braid | Livio Ferretti (Bern) |
| May 27 | Goodwillie calculus and \infty-categories | Johannes Witzig |
| June 3 | Excisive Approximation of l^1-Homology | Johannes Witzig |
| June 10 | Integral foliated simplicial volume and ergodic decomposition | Giovanni Sartori |
| June 17 | Concordance and alternation numbers of positive 3-braid knots (and a knot homology invariant) | Paula Truöl (ETHZ) |
| June 24 | A tale of two algebraic notions: left orderability and local indicability (abstract) | Yash Lodha (Universität Wien) |
| July 1 | Gauge-theoretic invariants of three-manifolds with a torus boundary component, and contact geometry | Tom Hockenhull (MPIM Bonn) |
| July 8 | Graph braid groups and Topological Complexity (M 311) | Giada Serafini (HHU Düsseldorf) |
| July 15 | L^2-invariants and Representation theory (M 311) | Han Zhicheng (G-A-U Göttingen) |
| July 22 | Thurston Spine of Teichmueller space | Ingrid Irmer |
| July 29 | Representations of fundamental groups via instantons | Felix Eberhart |
Scheduled meetings/talks in WS 21/22
| Date | Topic | Speaker |
| October 19, 10:15, M 103 (hybrid on demand) | Computability and L2-Betti numbers | Matthias Uschold |
| October 26, 10:15, M 201 (?) | Pachner's theorem, II | Julian Hannes |
| November 2, 10:15, M 201 (?) | Computability and L2-Betti numbers II (moved to Nov 16; instead we talked on Sigma invs and OEIS) | Matthias Uschold |
| November 9, 10:15, M 201 (?) | Spectral sequences in bounded cohomology | Daniel Echtler |
| November 16, 10:15, M 311 (hybrid on demand) | Computability and L2-Betti numbers II | Matthias Uschold | November 23, 10:15, M 311 (hybrid on demand) | Seifert genus and multicurves | Benedikt Aubeck |
| November 30, 10:15, M 311 (hybrid) | Bits and pieces (possibly also triple points!) | everybody |
| December 7, 10:15, M 311 (hybrid) | aspherical manifolds and simply(cial) thanks à vous(lume) | Marco Moraschini |
| December 14, 10:15, online | Smooth structures on non-compact 4-manifolds | Isacco Nonino (U Bonn) |
| December 21, 10:15, online | Enlargeability and Relativitiy | Jonathan Glöckle |
| January 11, 10:15, M 311 (hybrid on demand) | The Thom-Pontryagin construction | Stefan Friedl |
| January 18, 10:15, M 311 (hybrid on demand) | The Arf invariant and pi_{n+2}(S^n) | Stefan Friedl |
| January 25, 10:15, M 311 (hybrid on demand) | Realizing groups via graphs of groups with restricted vertices | Alessandro De Innocentiis |
| February 1, 10:15 | From genera to number theory | Wenbo Liao |
| February 8, 10:15, probably online | tba | Kevin Li (University of Southampton) |
| February 25, 8:15, online | TDA | Linda Hu |
Scheduled meetings/talks between SS 2021 and WS 21/22
| Date | Topic | Speaker |
| September 17, 11:00, H 31 | The universal covering from a categorial point of view | Benedikt Löhlein |
| October 8, time: 11:00, location: H 31 (hybrid) | The Novikov additivity theorem | Stefan Friedl |
| October 15, 11:00, M 101 (hybrid) | Strong Haken via Sphere Complexes | Sebastian Hensel (LMU) |
Scheduled meetings/talks in SS 2021 (online)
| Date | Topic | Speaker |
| April 13 | The (generalised) Toeplitz problem | Ulrich Steindl |
| April 20 | no talk | |
| April 27 | Bring your favourite group! | everybody |
| May 4 | LS-cat and applications | Marco Moraschini |
| May 11 | no talk (SFB prep) | SFB subset |
| May 18 | How to see a singularity | Filip Misev |
| May 25 | no talk! | (Whit Tuesday) |
| May 26 (Wed!!) | Complexity of Seifert manifolds | Valentina Falcioni (Bologna) |
| 10:15--11:45 if there is no Oberseminar; otherwise, we will move to 8:30--10:00. | ||
| June 1 | no talk! | (SFB eval) |
| June 8 | Bring your favourite group! II | everybody |
| June 15 | Categorical invariants of groups via classifying spaces for families | Kevin Li (University of Southampton) |
| June 22 | L^p-geometry of diffeomorphism groups: old and new results | Michael Brandenbursky (virtual Humboldt guest) |
| June 29 | Trees and mapping class groups | José Pedro Quintanilha |
| July 6 | CAT(0)-Geometry | Simon Stahl |
| July 13 | Cancellation of handles | Jan Zwank |
Scheduled meetings/talks in 02--04 2021 (online)
| Date | Topic | Speaker |
| February 25 | Octonionic projective space | Stefan Friedl |
| March 4 | Spatial graphs | José Pedro Quintanilha/Lars Munser |
| March 11 | A pedestrian's view of Fukaya categories of surfaces | Claudius Zibrowius |
| March 18 | Sagemath interface to knotinfo | Sebastian Oehms |
| March 25 | Sperner's Lemma | Lukas Lewark |
| April 1 | Pachner's theorem | Julian Hannes |
Scheduled meetings/talks in WS 2020/21 (online)
| Date | Topic | Speaker |
| October 2 (Fri!) | Conway mutation in link Floer, Khovanov and Bar-Natan homology | Claudius Zibrowius |
| October 8 (Thu!) | Projective modules and the homotopy classification of CW-complexes | Johnny Nicolson (UCL) |
| October 12 (Mon! 10:15) | Conway mutation in link Floer, Khovanov and Bar-Natan homology; part II | Claudius Zibrowius |
| October 15 (Thu!) | A lower bound on the stable 4-genus of knots | Damian Iltgen |
| October 22 (Thu!) | Stallings Theorem and link concordance | Lars Munser |
| October 29 (Thu!) | Mapping classes are almost determined by their finite quotient actions | José Pedro Quintanilha |
| November 3 | Real-world amenable coverage problems and bounded cohomology | Pietro Capovilla |
| November 10 | Integral foliated simplicial volume of mapping tori | Mathias Steinhuber |
| November 17 | Khovanov homology and the unknotting number | Laura Marino |
| November 24 | What are the Betti numbers of closed manifolds? | Matthias Kreck (Bonn) |
| December 1 | Introduction to the Isabelle proof assistant | Peter Bonart |
| December 8 | On the Berstein-Svarc theorem in dimension 2 | Habib Alizadeh |
| December 15 | Mapping class groups of aspherical manifolds | Christoph Winges |
| January 12 | arXivology | everybody |
| January 19 | An introduction to TQFTs | George Raptis |
| January 26 | Convergence of twisted Alexander polynomials | Georg Lipp |
Scheduled meetings/talks in SS 2020 (online)
| Date | Topic | Speaker |
| May 7 | Simplicial volume via normalised cycles | Marco Moraschini |
| May 14 | Milnor-Wood ohne Kontaktverbot (but in English) | Jonathan Bowden |
| May 21 | -- | Holiday |
| May 28 | Berkovich spaces | Miriam Prechtel |
| June 4 | Higher multiplicities of the Dirac operator | Julian Seipel |
| June 11 | -- | Holiday |
| June 18 | Topology without topology | Stefan Friedl |
| June 25 | Normed p-adic amenability | Francesco Fournier Facio (ETH Zürich) |
| July 2 | Products | Stefan Friedl |
| July 9 | More products | More Friedl |
| July 16 | Twisted Kuperberg invariants and Reidemeister torsion | Daniel López-Neumann |
| July 23 | The Hopf conjecture on mapping degrees | Michael Friesen |
Scheduled meetings/talks in WS 2019/20
| Date | Topic | Speaker |
| October 18 | Let X be a scheme ... | Johannes Witzig |
| October 25 | Classifying spaces and orbit categories | Daniel Echtler |
| November 1 | holiday | |
| November 8 | Descriptive set theory and forcing | Kristin Geßler |
| November 15 | The l^1-semi-norm on singular homology in degree 2 | Stephanie Ortmann |
| November 22 | Split-braid-merge diagrams, 3-manifolds, and conjugacy in a braided Thompson group | Yuri Santos Rego (OvGU Magdeburg) |
| November 29 | Higer order intersection numbers in 4-manifolds | Lars Munser |
| December 6 | no talk (Bavarian Geometry and Topology Meeting, Augsburg) | -- |
| December 13 | More intersection numbers | Lars Munser |
| December 20 | ||
| January 10 | The uniform boundary condition on free groups | Simon Lang |
| January 17 | The Cimasoni-Florens signatures of links | Andreas Wicher |
| January 24 | The maximum volume of hyperbolic polyhedra (in M311!) | Giulio Belletti (Scuola Normale Superiore, Pisa) |
| January 31 | Homological algebra for l^1-homology | Florian Greindl |
| February 7 | Chromatische Zahl von Kneser-Graphen und Borsuk-Ulam-Satz | Tobias Frey |
| February 26 (Wed, 10:15) | Daniel Grünbaum |
Scheduled meetings/talks in SS 2019
| Date | Topic | Speaker |
| April 26 | Prime decomposition of high-dimensional manifolds | Stefan Friedl |
| May 3 | Discrete Morse theory | Michał Marcinkowski (Wrocław) |
| May 10 | no talk, but there is an extra talk on May 16 (see below) | |
| May 16 | 14:30--15:30, M104; Whitney towers and higher order intersection numbers | Lars Munser (Bonn) |
| May 17 | Excision (from a different viewpoint) | Johannes Witzig |
| May 23 | 15:00--16:00, M104; Homology operations of little 2-cubes algebras | Domenico Marasco (Bonn) |
| May 24 | Introduction to sl_3 homology of knots | Carlo Collari () |
| May 31 | The Reidemeister-Schreier algorithm | Muriel Garcia |
| June 7 | Twist knots and Casson-Gordon invariants | Damian Iltgen |
| June 14 | Stable classification of 4-manifolds | Benjamin Ruppik (Bonn) |
| June 21 | The table theorem | José Pedro Quintanilha |
| June 28 | Excision: The wishlist | Johannes Witzig |
| July 5 | Chromatic number of groups (8:25--9:55!) | Matthias Uschold |
| July 12 | Hashing via expander graphs | Yannick Lautner |
| July 19 | The Svarc-Milnor Lemma | Pia Knerich |
| July 26 | On the isomorphism problem for (hyperbolic) one-relator groups | Alan Logan (Heriot-Watt University) |
| August 2 | The rendez-vous value of topological spaces | Jan-Philipp Zwank |
Scheduled meetings/talks in WS 2018/19
| Date | Topic | Speaker |
| October 19 (M311!) | Lower bounds on Dehn functions of residually free groups | Claudio LLosa-Isenrich (PSUD) |
| October 26 | Minimal stretch factors in the extended mapping class groups | Livio Liechti (IMJ) |
| November 2 | no talk | -- |
| November 9 | Hilbert spaces over non-archimedean fields | Raphael Schmidpeter |
| November 16 (10:00 s.t.!) | Hopf algebras in Galois theory | Linda Hu |
| November 23 | Vassiliev invariants via manifold calculus | Yuqing Shi (Bonn) |
| November 30 | Lagrangian relations, cobordisms and the Maslov index | Enrico Toffoli |
| December 7 | part 2 | Enrico Toffoli |
| December 14 | Geometry/Topology meeting in Augsburg | |
| December 21 | Bieri-Neumann-Strebel Transchromatic Theory with Quasi Theory | Gerrit Herrmann |
| January 11 | Scanning maps (?) | Luigi Caputi |
| January 18 | Some faces of the Poincaré homology 3-sphere | José Pedro Quintanilha |
| January 25 | Simplicial Poincaré Duality | Bruno Mazorra |
| (additional talk of the seminar Topology vs. Combinatorics) | ||
| February 1 | tba | Alexandra Kjuchukova (MPIM) |
| February 8 | moved to Wed, Feb 6, 14:00 | Kai Zehmisch (Gießen) |
Scheduled meetings/talks in SS 2018
| Date | Topic | Speaker |
| April 12 | Fibred classes | Stefan Friedl |
| April 19 | Homological stability for Artin monoids | Rachael Boyd (University of Aberdeen) |
| April 26 | Irrfahrten, Satz von Polya | Leonhard Beutlhauser |
| May 3 | Irrfahrten auf 3-Mannigfaltigkeiten | Richard Mante |
| May 10 | -- | Ascension Day |
| May 17 | Exceptional manifolds | Stefan Friedl |
| May 24 | Surgery theory for dummies/beginners | Markus Land |
| May 31 | -- | Corpus Christi |
| June 7 | Klassifikation von Seifert-gefaserten 3-Mannigfaltigkeiten | Felix Eberhart |
| June 14 | 10 Reasons why profinite groups are important in the world around you | José Pedro Quintanilha |
| June 21 | Der Satz von Helly | Julian Hannes |
| June 28 | Configuration spaces of linkages | Dennis Zumbil |
| July 5 | A Tale of Three Embeddings of Group Rings | Fabian Henneke (Bonn) |
| July 12 | An introduction to machine learning | Jonas Kleinöder |
| July 19 | Simplicial volume of surfaces with finite coefficients | Michael Friesen |
Formalities/Leistungsnachweis
entry in the commented list of all courses.Last change: 10/2024
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