Activities
recorded since 2000



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Upcoming events (organisation or active participation)

  • Research stay (host Prof. Yohei Komori), Waseda University, 1 week, January 2024
  • "Leonardo Math Camp" for talented high school pupils, Les Diablerets (Switzerland), 11 - 14 October 2023; conducted together with Matthieu Jacquemet (HES Sion / UniFR), Livio Liechti (UniFR) and Damaris Meier (UniFR); main organiser
  • Geometry Seminar, Waseda University, 20 January 2023; invited speaker


Research Seminars

  • Oberseminar Geometrie, since 2006

  • Graduate Seminar on Geometry, Andreas Bernig, Bruno Colbois, Ruth Kellerhals, Bern 2004-2006

  • Oberseminar Geometrie, Ruth Kellerhals, Thomas Zehrt, Fribourg 2000-2004


Events (organisation or active participation)

  • Conference on geometry, arithmetic and dynamics of discrete groups, Moscow Institute of Physics and Technology, Dolgoprudny, 12 - 16 December 2022; invited participant - participation cancelled due to the war of Russia against Ukraine
  • TecDay (SATW), Modul "Dreiecke mit Winkelsumme null?", Kantonsschule Olten, 01.12.2022
  • TecDay (SATW), Modul "Dreiecke mit Winkelsumme null?", Alte Kantonsschule Aarau, 01.03.2022
  • COGENT Seminar, October 25, 2021, invited speaker; online seminar organised by Philippe Elbaz-Vincent, Graham Ellis, Paul Gunnells and Haluk Sengun
  • Special Geometry Seminar, speakers Brent Everitt (York University) and John Parker (Durham University), University of Fribourg, October 6, 2021; organiser
  • Research stay, hosted by Proffs. Stephan Tillmann and Anne Thomas, University of Sydney, 2 weeks January, 2019
  • PhD thesis defense of Tomoshige Yukita, 15 November, 2018, Waseda University; external expert
  • TecDay (SATW), Modul "Dreiecke mit Winkelsumme null?", Gymnasium Thun, 21.03.2018
  • Workshop on "Hyperbolic Geometry Beyond Dimension Three", American Institute of Mathematics AIM SQuaRE, San Jose, July 17 - 23, 2017; invited participant
  • XXIII Rolf Nevanlinna Colloquium, Zürich, June 12 - 17, 2017;
    member Nevanlinna Board (together with Kari Astala (University of Helsinki), Pekka Koskela (Jyväskylä), Eero Saksman (University of Helsinki); Zoltan Balogh (Bern), Urs Lang (ETH Zürich); Toshiyuki Sugawa (Tohoku))
  • Journées de Géométrie Hyperbolique 2017, Workshop, University of Fribourg, March 23 - 24, 2017;
    speakers are Martin Deraux (Grenoble), Edoardo Dotti (Fribourg), Simon Drewitz (Fribourg; tbc), Vincent Emery (Bern), Anna Felikson (Durham), Michihiko Fujii (Okinawa), Rafael Guglielmetti (Fribourg), Ann Kiefer (Bielefeld), Olivier Mila (Bern)
  • Workshop on "Discrete Geometry", University of Auckland, February 15 - 16, 2017; invited speaker
  • Workshop on "Hyperbolic Geometry Beyond Dimension Three", American Institute of Mathematics AIM SQuaRE, San Jose, July 18 - 22, 2016; invited participant
  • Workshop Growth 3, Waseda University, Tokyo March 31 - April 1, 2016; invited speaker
  • TecDay (SATW), Modul "Dreiecke mit Winkelsumme null?", Bündner Kantonsschule, Chur, 26.02.2016
  • Journées de Géométrie Hyperbolique 2015, Workshop, University of Fribourg, October 15 - 16, 2015; ;
    speakers are Vincent Emery (Bern), Jordane Granier (Fribourg), Rafael Guglielmetti (Fribourg), John Parker (Durham), John Ratcliffe (Vanderbilt), Pavel Tumarkin (Durham)
  • Workshop on "Hyperbolic Geometry Beyond Dimension Three", American Institute of Mathematics AIM SQuaRE, San Jose, July 20 - 24, 2015; invited participant
  • "Topics in Negative Curvature", a conference in honour of the 70th birthday of Hans-Christoph Im Hof;
    4 - 5 August 2014, Mathematical Institute, University of Basel (Switzerland);
    speakers : C. Bavard (Bordeaux), P. Buser (EPF Lausanne), K. Grove (Notre Dame), J. Ratcliffe (Vanderbilt), P. Tumarkin (Durham), E. Vinberg (Moscow);
    organiser : R. Kellerhals (Fribourg);
    click here for the poster
  • Mini Workshop "Growth2", OCAMI, Osaka City University, February 3 - 4, 2014; invited speaker
  • PhD thesis defense of Yuriko Umemoto, 30 January, 2014, OCAMI, Osaka City University; external expert
  • TecDay (SATW), Modul D10 "Dreiecke mit Winkelsumme null?", Collège St. Michel, Fribourg, 20.11.2013
  • Geometric and Analytic Aspects of Group Theory,
    Institut Mittag-Leffler, January 16 - May 30, 2012; invited participant

Talks