Past talks

Spring 2021

  1. Jan 12. Alex Furman: Besson-Courtois-Gallot [ETDS 1996]

  2. Jan 19. Alex Furman: Besson-Courtois-Gallot, cont.

  3. Jan 26. Wouter Van Limbeek: Degree theorem in higher rank, after Connell-Farb

  4. Feb 2. Mikolaj Fraczyk: Vanishing of homology, after Connell-Farb-McReynolds

  5. Feb 9. Sebastian Hurtado: Rigidity of amalgamated products, after Besson-Courtois-Gallot

  6. Feb 16. Ethan Fricker: Marked length rigidity for surfaces, after Otal

  7. Feb 23. Alex Furman: Simplicial volume and Gromov-Thurston proof of Mostow rigidity for SO(n,1) n>2

  8. Mar 2. Sam Dodds: Positivity of simplicial volume for locally symmetric manifolds, after Lafont-Schmidt

  9. Mar 9. Wouter Van Limbeek: Introduction to bounded cohomology

  10. Mar 16. Wouter Van Limbeek: Introduction to bounded cohomology (continued)

  11. Mar 25: No seminar (Spring break)

  12. Mar 30: Yanlong Hao: Bounded Euler class and actions on the circle after Ghys

  13. April 6: Alex Furman: Volume rigidity of representations of hyperbolic lattices

  14. April 13: Alex Furman: Measure Equivalence Rigidity vs. Mostow rigidity

  15. April 20: Yanlong Hao: Some examples of surface group actions on the circle

  16. April 27: Steve Cantrell: The Manhattan curve and rigidity


Fall 2020

  1. Sept 8. Alex Furman: Some Intro, Planning, and Discussions.

  2. Sept 15. Alex Furman: Proximal elements in Zariski dense semi-groups

  3. Sept 22. Alex Furman/ Homin Lee: Loxodromic elements and Jordan projection

  4. Sept 29. Homin Lee: Benoist's theorem on Cartan projections

  5. Oct 6. Homin Lee / Wouter van Limbeek: Benoist's theorem on Cartan projections

  6. Oct 13. Wouter van Limbeek: Quotients of homogeneous spaces 2

  7. Oct 20. Wouter van Limbeek: Quotients of homogeneous spaces 3

  8. Oct 27. Mikolaj Fraczyk: Compact forms and decay of matrix coefficients (after Margulis)

  9. Nov 10. Sam Dodds: Joint spectrum (after Breuillard and Sert)

  10. Nov 17. Sam Dodds: Joint spectrum II (after Breuillard and Sert)

  11. Dec 1. Alex Furman: Uniform independence in linear groups (after Breuillard-Gelander)

Spring 2020

  1. Jan 21. Alex Furman: Arithmeticity of hyperbolic manifolds with many totally geodesic submanifolds (after Bader, Fisher, Miller, Stover)

  2. Jan 28. Alex Furman: Arithmeticity of hyperbolic manifolds with many totally geodesic submanifolds II (after Bader, Fisher, Miller, Stover)

  3. Feb 4. Yanlong Hao: Hyperbolic groups admit proper isometric actions on L^p-spaces with large p (after Nica).

  4. Feb 11. Alex Furman: Kazhdan groups have finite image in Diff^2(S^1).

  5. Feb 18. Ethan Fricker: Locally symmetric metrics minimize entropy under curvature bound (after Hamenstadt).

  6. Feb 25. Alex Furman: Holder's theorem and other Simultaneous Conjugation Problems.

Fall 2019 (Negatively curvature and growth)

  1. Aug 27, Alex Furman: Organizational and Introductory talk

  2. Sept 3, Sam Dodds: Patterson-Sullivan Theory I

  3. Sept 10, Sam Dodds: Patterson-Sullivan Theory II

  4. Sept 17, Sam Dodds: Patterson-Sullivan Theory III

  5. Sept 24, Alex Furman: Patterson-Sullivan Theory IV

  6. Oct 1, Yanlong Hao: Boundary representations for hyperbolic groups

  7. Oct 9, Yanlong Hao: Boundary representations for hyperbolic groups II

  8. Oct 15, Alex Furman: Burger's Manhattan curve, and Patterson-Sullivan measures in products of hyperbolic spaces

  9. Oct 22, Wouter Van Limbeek: Quasicircle boundaries and exotic almost-isometries

  10. Oct 29, Subhadip Dey, Orbits of Anosov subgroups from a Finsler point of view

  11. Nov 5, Sebastian Hurtado: Growth gap for groups acting on quaternionic hyperbolic space (after Corlette)

  12. Nov 19, Wouter van Limbeek: Maximal critical exponents via twisted Patterson-Sullivan measures (after Coulon-Dougall-Schapira-Tapie)

Spring 2019 (L^2-Betti numbers, B-S convergence, IRS, 7 Samurai paper/s):

  1. Jan 23. Alex Furman: Introduction to the 7s paper

  2. Feb 6. Wouter Van Limbeek: L^2-Betti numbers and Luck's Approximation Theorem

  3. Feb 13. Wouter Van Limbeek: L^2-Betti numbers and Luck's Approximation Theorem (cont.)

  4. Feb 20. Sam Dodds: Introduction to IRS (Invariant Random Subgroups)

  5. Feb 27. Sarnak's Lecture Series

  6. Mar 6. Yanglong Hao: IRS and Benjamini-Schramm convergence of locally symmetric spaces

  7. Mar 13. Mikolaj Fraczyk: Benjamini-Schramm convergence for congruence arithmetic lattices

  8. Mar 20. Alex Furman: On some theorems of Margulis, Stuck-Zimmer, Peterson and IRS

  9. Apr 3. Alex Furman: Margulis' Normal Subgroup Theorem

  10. Apr 17. Sebastian Hurtado: Heat flow and asymptotic of Betti numbers.

  11. Apr 24. Wouter Van Limbeek: Constructions of exotic IRS in rank one groups.

Fall 2018 Talks

  • September 11. Samuel Dodds: Hausdorff-Banach-Tarski "paradox"

  • September 18. Samuel Dodds: Banach-Ruziewicz problem on S^n with n>3 using property (T) (see [L] Section 3.4)

  • September 25. Wouter van Limbeek: Benoist-de Saxce paper, I.

  • October 2. Robert Kozma: Tarski's theorem - non-amenable groups are paradoxical.

  • October 16. Alex Furman: Sharp ergodic theorems along random walks for actions with spectral gap.

  • October 23. Alex Furman: Introduction to Bourgain-Gamburd machine.

  • October 30. Alex Furman: Bourgain-Gamburd machine, II.

  • November 6. Wouter van Limbeek: Weak version of Selberg's Theorem.

  • November 13. Sebastian Hurtado: Balog-Szemeredi-Gowers Lemma.

  • November 20. Wouter Van Limbeek: Benoist-de Saxce paper, II.

Spring 2018 Talks:

  • February 7. Organizational meeting and/or a short talk about "Aut(F_5) has property (T)"

  • February 28. Alex Furman: Properties of harmonic measure for a random walk on SL(d,R)

  • March 7. Alex Furman: On continuity of Lyapunov exponents

  • March 14. Alex Furman: On Gromov-Thurston's proof of Mostow rigidity

  • April 11, 25. Alex Furman: A theorem of Besson-Courtois-Gallot.

Fall 2017 talks:

  • September 7. Alex Furman: Intro to Ozawa's paper - affine isometric actions on Hilbert spaces

  • September 14. Olga Lukina: Selberg's lemma

  • September 21. Alex Furman: Reduced cohomology and harmonic cocycles

  • September 28. Sam Dodds: Polynomial growth and vanishing of reduced cohomology under weak mixing

  • October 5. Alex Furman: Groups without (T) have non-trivial reduced cohomology

  • October 19. Yanlong Hao: Congruence Subgroup Property

  • Oct 26, Nov 2. Jake Herndon: Boundedness of the homeomorphism group of a sphere

  • November 9, 16. Alex Furman: Oseledets Theorem

  • November 30. Alex Furman: Intro to random walks on semi-simple Lie groups

  • December 7. Alex Furman: Intro to harmonic functions and Furstenberg-Poisson boundary