Koivisto, Juhani
Juhani Koivisto
Tohtorikoulutettava
Doktorand
Doctoral student
Research
My research interests include: geometric group theory; coarse geometry; LCCG groups; and analysis on metric spaces. In particular, I have worked on generalizations of property (T) for reflexive Banach spaces; amenability of metric spaces; and controlled coarse homology of metric measure spaces. For automorphism groups of simplicial complexes I have obtained a spectral condition for the vanishing of L2 -cohomology with coefficients in uniformly bounded representations. For metric spaces, I have proved that each uniformly coarsely proper visual Gromov hyperbolic space with connected boundary containing at least two points is non-amenable. For uniform metric measure spaces supporting a local weak (1,1)-Poincaré inequality, I have completely characterised the vanishing of its fundamental class in the controlled coarse homology by a global Sobolev inequality.
Activities
Organiser of the Student Colloquium Fall 2014 - Spring 2016.
Publications
J. Koivisto, Automorphism groups of simplicial complexes and rigidity for uniformly bounded representations, Geom. Dedicata, April 2014, Volume 169, Issue 1, pp 57-82
Pre-prints
J. Koivisto, Non-amenability and visual Gromov hyperbolic spaces arXiv:1505.04662, accepted by Groups Geom. Dyn.
J. Koivisto, Characterising Sobolev inequalities by controlled coarse homology and applications for hyperbolic spaces arXiv:1402.5816, accepted by Rev. Mat. Iberoamericana
Teaching
Teaching assistant in: Introduction to Differential Geometry (Fall 2009, 2012); Metric Geometry (Fall 2013).
Visits
Technion, Israel Institute of Technology, 20 July -3 August 2013
Technion, Israel Institute of Technology, 14 January - 28 May 2014
University of Souther Denmark, 26 - 29 April 2016
Past conferences and meetings
Summer School in Geometric Analysis in Samos, Karlovassi, Samos (Greece) 31 May - 4 June 2010
Workshop on Geometric Group Theory, Heilbronn Institute, Bristol (England), 20-24 June 2011
Young Geometric Group Theory Meeting, Bedlewo (Poland), 9-13 January 2012
6th European Congress of Mathematics, Kraków (Poland), 2-7 July 2012
Young Geometric Group Theory II, The Technion, Haifa (Israel), 3-7 February 2013
3rd Young Geometric Group Theory Meeting, CIRM, Luminy, Marseille (France), 20-24 January 2014
Random Walks and Asymptotic Geometry of Groups, Institut Henri Poincaré, Paris (France), 24-28 March 2014
Mapping class groups and Teichmüller theory, Ramat HaNadiv, Haifa (Israel), 7-14 May 2014
Mathematics Meets Physics, University of Helsinki, Helsinki (Finland), 24-27 June 2014
24th Jyväskylä Summer School, Jyväskylä (Finland), 11-15 August 2014
Geometric and Combinatorial Group Theory, The Israel Institute for Advanced Study, Jerusalem (Israel), 14-20 December 2014
Young Geometric Group Theory IV, Sol Cress, Spa (Belgium), 11-17 January 2015
Saint Petersburg- Helsinki Math Colloquium, Chebyshev Laboratory, Saint Petersburg State University, Saint Petersburg (Russia), 5-7 May 2015
Summer School in Cohomology and Large Scale Geometry, Universität Regensburg, Regensburg (Germany), 27-31 July 2015
Geometric Function Theory meets Geometric Group Theory (GFT meets GGT), Banach Center, Warsaw (Poland), 15-17 October 2015
Young Geometric Group Theory V, KIT, Karlsruhe (Germany), 15-19 February 2016
Upcoming conferences
Danish-Norwegian workshop on operator algebras, Lusebu, Oslo (Norway), 5-8 January 2017
Yhteystiedot
Huone: B428
Osoite: PL 68 (Gustaf Hällströmin katu 2b)
00014 Helsingin yliopisto
Puhelin: (09) 191
Sähköposti: juhani.koivisto 'at' helsinki.fi
Kontaktinformation
Rum: B428
Adress: PB 68 (Gustaf Hällströms gata 2b)
00014 Helsingfors universitet
Telefon: (09) 191
Epost: juhani.koivisto 'at' helsinki.fi
Contact information
Room: B428
Address: P.O. Box 68 (Gustaf Hällströmin katu 2b)
FI-00014 University of Helsinki
Telephone: +358-9-191
Email: juhani.koivisto 'at' helsinki.fi