International young seminar on bounded cohomology and simplicial volume


Starting from Summer Semester 2020, this seminar aims at connecting young people working in the areas of simplicial volume, bounded cohomology and related subjects. It is also meant as an occasion for PhD students and young postdocs to give a talk on their research project or interests. Other people interested in the area are also welcome to attend. Notice that during the Winter Semester 2020, we organized a program mainly based on introductory talks (see the paragraph below).

Proceedings of the WS20 seminars:

In this volume (here in a preliminary version, the link to the published version will be soon available) you may find the collection of all reports from seminars given during WS20. Since the Winter Semester 2020 was devoted to foundational topics, we hope this book will serve as a gentle introduction to young mathematicians working in the field to topics of current research interest.[1]


Monday 16:00-17:30 (Central European Time).


16:00-16:15 Coffee break

16:15-17:00 Talk

17:00-17:30 Questions and discussion


The seminars are hosted in Marco's UR-zoom meeting room: 623 8922 3838.

The password is the solution of the following riddle "The dual theory of bounded cohomology" (no capital letters, it begins by h) followed by the last two digits of the current year without spacing.

Program of the WS21

18/10/2021 - Bruno Martelli (University of Pisa) - Hyperbolic 5-manifolds that fiber over the circle - Opening lecture (abstract) (video).

25/10/2021 - Giuseppe Bargagnati (University of Pisa) - Simplicial volume of contractible 3-manifolds (abstract) (video)

01/11/2021 - Holiday!

08/11/2021 - Kevin Li (University of Southampton) - Bounded cohomology of classifying spaces for families of subgroups (abstract)

15/11/2021 - Thorben Kastenholz (University of Göttingen) - The simplicial volume of manifolds fibering over spheres (abstract) (video)

22/11/2021 - Martin Nitsche (KIT) - Higher-degree bounded cohomology of transformation groups (abstract)

29/11/2021 - Yulan Qing (Fudan University) - The Large scale geometry of big mapping class groups (abstract)

06/12/2021 - Francesco Milizia (University of Pisa) - TBA

13/12/2021 - Nicolas Monod (EPFL) - TBA

20/12/2021 - TBA

10/01/2022 - TBA

17/01/2022 - Xiaofeng Meng (Fudan University) - TBA

24/01/2022 - TBA

31/01/2022 - TBA

07/02/2022 - TBA

Organizers of the WS21 Edition:

Caterina Campagnolo (ENS Lyon), Francesco Fournier-Facio (ETH Zurich) and Marco Moraschini (UR).

Program of the SS21

12/04/2021 - Nikolai Ivanov - Bounded cohomology and classical algebraic topology (abstract) (video) Opening lecture: 1 hour long starting at 16:00 (CET)

19/04/2021 - Morimichi Kawasaki (Aoyamagakuin University) - On the space of non-descending quasi-morphisms (abstract) (video)

26/04/2021 - Pietro Capovilla (University of Regensburg) - Amenable category and complexity (abstract) (video)

03/05/2021 - Bastien Karlhofer (University of Aberdeen) - Aut-invariant quasimorphisms on free products (abstract) (video) (slides)

Postponed to 28/06! 10/05/2021 - George Raptis (University of Regensburg)

17/05/2021 - Sofia Amontova (University of Geneva) - Cup products in bounded cohomology of the free group via aligned cochains (abstract) (video)

24/05/2021 - Holiday!

31/05/2021 - Roman Sauer (KIT) - Actions on Cantor spaces and macroscopic scalar curvature (abstract) (video)

07/06/2021 - Christophoros Neofytidis (Ohio State University) - Topological Kodaira dimension, mapping degree and the simplicial volume (abstract)

14/06/2021 - Lvzhou (Joe) Chen (UT Austin) - Stable torsion length (abstract) (video).

21/06/2021 - Clara Löh (University of Regensburg) - The spectrum of simplicial volume of non-compact manifolds (abstract)

28/06/2021 - George Raptis (University of Regensburg) - Local-to-global properties and bounded cohomology (abstract)

Organizers of the SS21 Edition:

Caterina Campagnolo (ENS Lyon), Francesco Fournier-Facio (ETH Zurich) and Marco Moraschini (UR).

Gong Talks:

Starting from December 14th, we have introduced a gong talk (approx. 5-10 mins) before each main talk. We aim to give the opportunity to master students and early PhD candidates to present themselves and give a quick overview on their research interests. Also gong research talks are welcome as well. We encourage everyone to submit a contributed gong talk to the organizers. Finally, in order to make this event more informal, we decided to not record any gong talk.

Program of the Gong Talks (WS20):

14/12/2020 - Pietro Capovilla (University of Regensburg) - Amenable category and classifying spaces

21/12/2020 - José Pedro Quintanilha (University of Regensburg) - Algorithmic recognition of spatial graphs (slides)

11/01/2021 - Henrique Souza (University of Brasilia) - Dëmushkin Groups and L^2 invariants (slides)

18/01/2021 - Kevin Li (University of Southampton) - Bredon cohomology of groups

01/02/2021 - Francesco Milizia (SNS Pisa) - \ell^\infty-cohomology

Program of the WS20:

2/11/2020 - Marco Moraschini (University of Regensburg) - Gromov's Mapping Theorem via multicomplexes (abstract) (slides) (video).

9/11/2020 - Filippo Sarti (University of Bologna) - The proportionality principle via hyperbolic geometry (abstract) (video).

16/11/2020 - Shi Wang (MPIM Bonn) - Positivity of simplicial volume via barycentric techniques (abstract) (video).

23/11/2020 - Lizhi Chen (Lanzhou University) - Gromov's systolic inequality via smoothing technique (abstract) (slides) (video).

30/11/2020 - Caterina Campagnolo (ENS Lyon) - Stable integral and foliated integral simplicial volume (abstract) (video).

7/12/2020 - Holger Kammeyer (KIT) - L^2-Betti numbers (abstract) (video).

14/12/2020 - Nicolaus Heuer (University of Cambridge) - Stable commutator length (abstract) (video) (slides).

21/12/2020 - Biao Ma (Côte d'Azur University) - Quasimorphisms on negatively curved groups - mapping class groups (abstract) (video).

11/01/2021 - Francesco Fournier Facio (ETH Zurich) - Extension of quasicocycles from hyperbolically embedded subgroups (abstract) (video).

18/01/2021 - Anton Hase (Technion) - Lie groups and Symmetric spaces (abstract) (video).

25/01/2021 - Alessio Savini (University of Geneva) - Continuous bounded cohomology, representations and multiplicative constants (abstract) (slides)(video) .

1/02/2021 - Filippo Baroni (SNS Pisa) - The proportionality principle via bounded cohomology (abstract) (video) .

Organizers of the WS20 Edition:

Caterina Campagnolo (ENS Lyon), Francesco Fournier Facio (ETH Zurich), Nicolaus Heuer (University of Cambridge) and Marco Moraschini (UR).

Program of the SS20 Edition (all the videos are available upon request):

27/04/2020 - Francesco Fournier Facio (ETH Zurich) - Combinatorics of infinite sums of Brooks quasimorphisms (abstract)

04/05/2020 - Shi Wang (MPIM Bonn) - Barycentric straightening and Gromov norm (abstract)

11/05/2020 - Nicolaus Heuer (University of Cambridge) - The spectrum of Simplicial Volume (abstract)

18/05/2020 - James Farre (Yale University) - Addition of geometric volume classes (abstract)

25/05/2020 - Steffen Kionke (University of Hagen) - p-adic simplicial volumes (abstract)

01/06/2020 - Public holiday

08/06/2020 - Alessandro Sisto (ETH Zurich) - Central extensions and bounded cohomology (abstract)

15/06/2020 - Filippo Sarti (University of Bologna) - Numerical invariants and bounded cohomology (abstract)

22/06/2020 - Gabriele Viaggi (Heidelberg University) - Volumes and random walks on mapping class groups (abstract) (slides)

29/06/2020 - Roberto Frigerio (University of Pisa) - Bounded cohomology, cohomology with bounded values and d-bounded cohomology (abstract) (slides)

06/07/2020 - Jonathan Bowden (University of Regensburg) - Quasi-morphisms on surface diffeomorphism groups (abstract)

13/07/2020 - Clara Löh (University of Regensburg) - Stable integral simplicial volume (abstract) (last seminar of this semester!)

Organizers of the SS20 Edition:

Caterina Campagnolo (ENS Lyon) and Marco Moraschini (UR).

[1] If you find any mistake, please do not hesitate to contact the organizers.

Updated 11 Oct 2021
by Marco Moraschini.

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