I am Sven Raum, working as associate professor at Stockholm University in Sweden. My research focuses on operator algebras and their interaction with groups and grouplike structures, such as Hecke algebras, groupoids, quantum groups and tensor categories. Important links between operator algebras and these objects are given by unitary representations and the algebras they generate, for example reduced group C*algebras and group von Neumann algebras.
Besides research mathematics, I enjoy thinking about didactics of higher education. In my free time, I like learning languages, doing sports and cooking.
Seminars
Currently I am one of the organisers of
Stockholm's Wednesday Zoom seminar with topics in algebra, geometry and representation theory.
GOAT
In spring 2022 we will start regular activities in our Grupp och Operatoralgebra Träff (GOAT, English: Group and operator algebra meeting).
HAOART Seminar
Due to the Corona pandemic, our seminar on Harmonic Analysis, Operator Algebras and Representation Theory (pronounced "Howard") is currently suspended in favor of Wednesday's Zoom Seminar.
All abstracts can be found in the SMC calender:
Link
Spring 2020

04.03.2020
Rolf Källström (Högskolan i Gävle)
Decompositions of Dmodules over finite maps and the correspondence with representations of finite groups

26.02.2020
Michael Hartz (University of Hagen)
Multipliers and operator space structure of weak products

05.02.2020
Eskil Rydhe (Lund University)
On LaplaceCarleson embeddings, and some aspects of the Fourier transform

29.01.2020
Wushi Goldring (Stockholm University)
Propagating algebraicity of automorphic representations via Langlands functoriality
Autumn 2019

04.12.2019
Odysseas Bakas (Lund University)
Remarks on a theorem of Pichorides

27.11.2019
Christian Bönicke (University of Glasgow)
Regularity properties for ample groupoids

13.11.2019
Yash Lodah (EPFL)
Finitely generated infinite simple groups of homeomorphisms of the real line

13.11.2019
Asaf Horev (Stockholm University)
Geometric representation theory and factorization homology on surfaces
(Joint with the NT seminar at 11 o`clock, room 306)

30.10.2019
Arno Kret (University of Amsterdam)
Construction of Galois representations for GSO_2n

04.09.2019
Ulrik Enstad (University of Oslo)
Timefrequency analysis on the adeles
Spring 2019

29.05.2019
Constanze Liaw (University of Delaware)
Generalizations of AleksandrovClark theory

22.05.2019
David Kyed (University of Southern Denmark)
Uniqueness questions for C*norms on group rings

15.05.2019
Alan Sola (University of Stockholm)
The Dirichlet space of the bidisk: a survey

08.05.2019
Nadia Larsen (University of Oslo)
Phase transitions and arithmetic subalgebras for Hecke C*algebras from number fields

24.04.2019
Magnus Goffeng (University of Gothenburg/Chalmers)
The dynamics and (noncommutative) geometry of Smale spaces
Publications
All my publications can be found on
MathSciNet,
zbMATH and
ArXiv.
Preprints

The ideal intersection property for essential groupoid C*algebras
with Matthew Kennedy, SeJin Kim, Xin Li and Dan Ursu
ArXiv (2021)

Ktheory of rightangled Hecke C*algebras
with Adam Skalski
ArXiv (2021)

Amenability, proximality and higher order syndeticity
with Matthew Kennedy and Guy Salomon
ArXiv (2020)

Factorial multiparameter Hecke von Neumann algebras and representations of groups acting on rightangled buildings
with Adam Skalski
ArXiv (2020)
Research articles

An algebraic characterization of ample type I groupoids
with Gabriel Favre
Semigroup Forum (online first) and the
ArXiv version

Measure equivalence for nonunimodular groups
with Juhani Koivisto and David Kyed
Transform. Groups 26 (2021)
and the
ArXiv version

Cartan subalgebras in dimension drop algebras
with Selçuk Barlak
J. Inst. Math. Jussieu 20 (2021) No. 3, 725755.
and the
ArXiv version

Measure equivalence and coarse equivalence for locally compact amenable groups
with Juhani Koivisto and David Kyed
Group, Geom. and Dyn. 15 (2021) No. 1, 223267
and the
ArXiv version

C*simplicity (after Breuillard, Haagerup, Kalantar, Kennedy and Ozawa)
Sven Raum
Séminaire Bourbaki, exposé 1158, Astérisque 422 (2020)
and the
Preprint version

Locally compact groups acting on trees, the type I conjecture and nonamenable von Neumann algebras
with Cyril Houdayer
Comm. Math. Helv. 76 (2019) No. 1, 185219
and the
ArXiv version

C*simplicity of locally compact Powers groups
J. Reine Angew. Math. 748 (2019) 173205
and the
ArXiv version
Erratum to this article

C*superrigidity of 2step nilpotent groups
with Caleb Eckhardt
Adv. Math. 338 ( 2018), 175195 and the ArXiv version

Higher l^{2}Betti numbers of universal quantum groups
Julien Bichon and David Kyed
Can. Math. Bull. 61 (2018), No. 2, 225235 and the ArXiv version

Traces on reduced group C*algebras
with Matthew Kennedy
Bull. Lond. Math. Soc. 49 (2017) No. 6, 988990 and the ArXiv version

L^{2}Betti numbers of rigid C*tensor categories and discrete quantum groups
with David Kyed, Stefaan Vaes and Matthias Valvekens
Analysis & PDE 10 (2017), No. 7, 17571791 and the ArXiv version

On the l^{2}Betti numbers of universal quantum groups
with David Kyed
Math. Ann. 369 (2017), No. 34, 957–975 and the
ArXiv version

Cocompact amenable closed subgroups: weakly inequivalent representations in the leftregular representation
Int. Math. Res. Not., (2016), No. 24, 76717685 and the ArXiv version

The full classification of orthogonal easy quantum groups
with Moritz Weber
Commun. Math. Phy. 341 (2016) No. 3, 751779 and the
ArXiv

Easy quantum groups and quantum subgroups of a semidirect product quantum group
with Moritz Weber
J. Noncommu. Geo. 9 (2015) No. 4, 12611293 and the ArXiv version

Asymptotic structure of free ArakiWoods factors
with Cyril Houdayer
Math. Ann. 363 (2015) No. 12, 237267 and the ArXiv version

BaumslagSolitar groups, relative profinite completions and measure equivalence rigidity
with Cyril Houdayer
J. Topol. 8 (2015), 295313 and the ArXiv

The combinatorics of an algebraic class of easy quantum groups
with Moritz Weber
Infin. Dimens. Anal. Quantum Probab. Relat. Top. 17, No. 3 (2014) and the ArXiv version

Amalgamated free product type III factors with at most one Cartan subalgebra
with Rémi Boutonnet and Cyril Houdayer
Compositio Math. 150 (2014), 143174 and the ArXiv version

On the classification of free Bogoljubov crossed product von Neumann algebras by the integers
Groups, Geom. and Dyn. 8 (2014) No. 4, 12071245 and the ArXiv version

Tensor C*categories arising as bimodule categories of II_{1} factors
with Sébastien Falguières
Adv. Math. 237 (2013), 331359 and the ArXiv version

Stable orbit equivalence of Bernoulli actions of free groups and isomorphism of some of their factor actions
with Niels Meesschaert and Stefaan Vaes
Expo. Math. 31 (2013), 274294 and the ArXiv version

Isomorphisms and fusion rules of orthogonal free quantum groups and their complexifications
Proc. Amer. Math. Soc. 140 (2012), No. 9, 32073218 and the ArXiv version
Other work

Lecture notes about CreutzPeterson's "Character rigidity for lattices and commensureators"
Written for the Arbeitsgemeinschaft "Superrigidity" at MFO, 2014
Lecture C3 and Lecture C4

A connection between easy quantum groups, varieties of groups and reflection groups
with Moritz Weber
This is an arXiv preprint from 2012 which is not intended for publication. Please cite instead the appropriate article among my remaining work with Moritz.

Categories of representations and classification of von Neumann algebras and quantum groups
My PhD thesis under the supervision of Stefaan Vaes submitted in 2013 at KU Leuven.
Invited talks
Conference talks and lecture series
2021

November 2021
"Simplicity and the ideal intersection property for essential groupoid C*algebras"
at the DanishNorwegian Operator Algebras meeting, Trondheim, Norwary.
2019

October 2019
"C*superrridity"
at MFO, Oberwolfach, Germany during the miniworkshop "Operator algebraic quantum groups".

September 2019
"C*superrridity"
at BIRS, Banff, Canada during the workshop "Classification problems in von Neumann algebras".

July 2019
"Group C*algebras: classical and modern"
series of five lectures at the Sophus Lie Center, Nordfjordeid, Norway during the summer school "Analysis, Geometry and PDE".

June 2019
"Cartan subalgebras in dimension drop algebras"
at ICMAT, Madrid, Spain during the International Conference "Operator Algebras, Groups and Applications to Quantum Information".

February 2019
"C*superrigidity"
two lectures at the Fields Insitute, Toronto, Canada during the Southern Ontario Operator Algebras Seminar 2019.

January 2019
"C*superrigidity"
series of four lectures at IMP, Tehran, Iran during the workshop "Quantum groups".
2018

May 2018
"C*superrigidity of 2step nilpotent groups"
at the University of Münster, Germany, at the occasion of the conference NCGOA 2018.

March 2018
"L^{2}Betti numbers of universal quantum groups"
at the Université de Caen, France, during the Journées de catégories tensorielles et analyse.

February 2018
"C*superrigidity"
at the American Institute of Mathematics, San José, CA, USA, during the Workshop "Classification of group von Neumann algebras".
2017

October 2017
"Groups acting on trees: representation theory and operator algebras"
in Sendai, Japan, during the Workshop "Ergodic and Geometric Group theory in Sendai".

October 2017
"C*superrigidity of virtually Abelian groups"
at IMPAN, Poland, during the Workshop "Operator Algebras, Geometry, and Actions".

July 2017
"C*superrigidity of virtually Abelian groups"
at Institut Henri Poincaré, France, during the Workshop "Von Neumann algebras and measured group theory".
2016

October 2016
"Operator algebras of locally compact groups acting on trees"
at Université de Bordeaux, France, during the Workshop "Groupes et algèbres de von Neumann".

August 2016
"Nonamenable von Neumann algebras of groups acting on trees"
in MFO, Germany, during the Workshop "C*algebras".

July 2016
"Operator algebras of locally compact groups acting on trees"
at HIM, Bonn, Germany, during the workshop "Von Neumann algebras".

June 2016
"Operator algebras of locally compact groups acting on trees"
at Université de Paris 6, France, during the conference "Polish groups and geometry".

April 2016
"Operator algebras of locally compact groups acting on trees"
at the MittagLeffler Institute, Sweden, during the workshop "Classification and dynamical systems II: Von Neumann Algebras".

January 2016
"Locally compact C*simple groups"
lecture series at IPM, Tehran, Iran at the occasion of the workshop "C*dynamics".
2015

July 2015
"The classification of orthogonal easy quantum groups"
in Herstmonceux, UK at the occasion of the Fields institute conference on quantum groups and quantum information theory.

June 2015
"Locally compact C*simple groups"
in MFO, Germany, during the Workshop "Noncommutative geometry".

June 2015
"Powers group methods for locally compact groups acting on trees"
in Copenhagen, Denmark at the occasion of the workshop "Representation theory of groups, quantum groups, and operator algebras".

May 2015
"Powers group methods for locally compact groups acting on trees"
in Neuchâtel, Switzerland at the Group Theory Day.

May 2015
"Powers group methods for locally compact groups acting on trees"
in Nashville, USA, at the occasion of the conference NCGOA 2015.

April 2015
"Powers group methods for locally compact groups acting on trees"
in Münster, Germany, at the occasion of the workshop "C*algebras: Structure and Classification".
2014

September 2014
"BaumslagSolitar groups, relative profinite completions and measure equivalence rigidity"
in Kyoto, Japan, at the occasion of the workshop on recent developments in operator algebras.

July 2014
"The classification of easy quantum groups"
in Amsterdam, the Netherlands, at the occasion of the international workshop on operator theory and its applications.

May 2014
"Structure theory for von Neumann algebras: solidity"
at the University of FrancheComté in Besançon, France, during the journées d'analyse fonctionelle BesonçonNeuchâtel.

March 2014
"Character rigidity for lattices and commensurators (after CreutzPeterson)"
in MFO, Germany, during the Arbeitsgemeinschaft "Superrigidity".
2013 and before

December 2013
"BaumslagSolitar groups, relative profinite completions, and measure equivalence rigidity"
in Caen, France, at the occasion of the Arbre de Noël.

January 2013
"A duality between easy quantum groups and reflection groups"
in Tokyo, Japan, at the occasion of a workshop on operator algebras.

September 2012
"Sur la classification des produits croisés de Bogoliubov libre"
in Lyon, France, at the occasion of the meeting of the ANR project NEUMANN.

May 2011
"All finite C*tensor categories are bimodule categories of a II_{1} factor"
in Paris, France, at the occasion of the FrancoItalien meeting of GDRE GREFIGENCO.

September 2010
"Is every finite C*tensor category the bimodule category of a II_{1} factor?"
in Caen, France, at the occasion of the focused semester on quantum groups of the EU Noncommutative Geometry Network.

September 2010
"Every finite C*tensor category is the bimodule category of a II_{1} factor"
in Brussels, Belgium, at the occasion of the PhD day of the Belgium Mathematical Society.

February 2010
"Fusion rules of free orthogonal quantum groups"
in Cardiff, UK, at the occasion of the period on planar algebras and physics.

January 2010
"Fusion rules of free orthogonal quantum groups"
in Copenhagen, Denmark, at the occasion of the masterclass on von Neumann algebras and group actions.
Colloquium and seminar talks
2022

May 2022
"Simplicity of essential groupoid C*algebras"
in the Pure Math Colloquium of the University of Sheffield.
2021

November 2021
"Simplicity of essential groupoid C*algebras"
in the group theory seminar at UCLouvain.

October 2021
"Simplicity of essential groupoid C*algebras"
in the analysis seminar at the Washington University in St. Louis.

April 2021
"Rightangled Hecke operator algebras"
in the seminar on ergodic and geometric group theory at EPF Lausanne.

April 2021
"Rightangled Hecke operator algebras"
in the operator algebra seminar at Purdue University.

March 2021
"Rightangled Hecke operator algebras"
in the seminar Géométrie, Groupes et Dynamiques at ENS Lyon.

March 2021
"Superrigidity for group operator algebras"
in the IM PAN Young Researchers Colloquium.

March 2021
"Rightangled Hecke operator algebras and representation theory"
in the UCSD Functional Analysis Seminar.

February 2021
"Why group theorists could care about operator algebras"
in the Online Seminar on Probabilistic and Geometric Group Theory.
2020

October 2020
"Structure of Hecke von Neumann algebra and appications to representation theory"
in the TokyoKyoto online operator algebra seminar.

July 2020
"C*superrigidity"
in the UK Virtual Operator Algebras Seminar.

February 2020
"From Poisson boundaries to proximal boundaries"
at the University of Copenhagen, Denmark, in the operator algebra seminar.
2019

December 2019
"C*superrigidity of 2step nilpotent groups"
at University ParisSud, France, in the research seminar GAN.

April 2019
"C*superrigidity of 2step nilpotent groups"
at the University of Glasgow, UK, in the analysis seminar.

March 2019
"C*superrigidity of 2step nilpotent groups"
at the University of Oslo, Norway, in the operator algebra seminar.

January 2019
"C*simpllicity"
at IHP, Paris, France, in the Séminaire Bourbaki.
2018

December 2018
"Superrigidity for group operator algebras"
at the University of Waterloo, Canada, in the Pure Math Colloquium.

August 2018
"C*superrigidity of 2step nilpotent groups"
at Chalmers, Gothenburg, Sweden, in the Analysis and Probability seminar.

May 2018
"C*superrigidity of nilpotent groups"
at EPFL, Switzerland, in the topology seminar.

February 2018
"C*superrigidity"
at RIMS, Kyoto University, Japan.

February 2018
"Cartan subalgebras in dimension drop algebras"
at Nagoya University, Japan, in the research seminar of the analysis group.
2017

November 2017
"Cartan subalgebras in dimension drop algebras"
at Copenhagen University, Denmark, in the research seminar of the operator algebra work group.

November 2017
"Groups acting on trees: representation theory and operator algebras"
at the University of Southern Denmark, Odense, Denmark, in the research seminar of the operator algebra work group.

August 2017
"C*superrigidity of virtually abelian groups"
at Chiba University, Japan, in the analysis seminar.

June 2017
"Groups acting on trees: representation theory and operator algebras"
at the Isaac Newton Institute, Cambridge, UK, in the operator algebras seminar.

May 2017
"C*superridigity of virtually abelian groups"
at Université de Neuchâel, Switzerland, in the groups and analysis seminar.
2016

December 2016
"On the type I conjecture for groups acting on trees"
at EPFL, Switzerland, in the EGG seminar.

November 2016
"On the type I conjecture for groups acting on trees"
at ETH Zürich, Switzerland, in the geometry seminar.

April 2016
"Algèbres d'opérateurs de groupes agissants sur les arbres"
at Université Catholique de Louvain, Belgium, in the group theory seminar.

April 2016
"C*simplicity: from discrete to locally compact groups"
at Hokkaido University, Japan, in the analysis research seminar.

March 2016
"C*simple and nonC*simple locally compact groups"
at University ParisSud, France, in the research seminar GAN.

March 2016
"C*simple and nonC*simple locally compact groups"
at Copenhagen University, Denmark, in the research seminar of the operator algebra work group.

March 2016
"C*simple and nonC*simple locally compact groups"
at EPFL, Switzerland, in the research seminar for ergodic and geometric group theory.
2015

November 2015
"Locally compact C*simple groups"
at the University of Münster, Germany, in the research seminar of the noncommutative geometry workgroup.

October 2015
"Locally compact C*simple groups"
at the University of Glasgow, Scotland, in the analysis seminar.

July 2015
"Generalised symmetries of quantum spaces"
at Keio University in Yokohama, Japan, in the monthly colloquium of the math department.

July 2015
"C*simplicity of locally compact Powers groups"
at Ochanomizu University in Tokyo, Japan, in the operator algebras seminar.

January 2015
"Free probability aspects of easy quantum groups"
at Kyushu University in Fukuoka, Japan, in the operator algebras seminar.

January 2015
"Character rigidity for lattices in higher rank Lie groups (after CreutzPeterson and Peterson)"
at RIMS in Kyoto, Japan, in the Kansai operator algebras seminar.
2014

October 2014
"The classification of easy quantum groups"
at Tokyo University, Japan, in the operator algebras seminar.
2013 and before

November 2013
"The classification of orthogonal partition quantum groups (easy quantum groups)"
at the University of FrancheComté in Besançon, France, in the functional analysis seminar.

May 2013
"Group von Neumann algebras of locally compact HNNextensions"
at the University of Oxford, UK, in the junior geometric group theory seminar.

December 2012
"What is ... superrigidity?"
at KU Leuven, Belgium, in the PhDColloquium.

November 2012
"On the classification of free Bogoliubov crossed products of the integers"
at Université catolique de Louvain, Belgium, in the group theory seminar.

October 2012
"Tensor C*categories arising as bimodule categories of a II_{1} factor"
at the University of Münster, Germany, in the research seminar of the noncommutative geometry workgroup.

June 2012
"Von Neumann algebras and their bimodule categories"
at Saarland University, Germany, in the functional analysis seminar.

May 2012
"Les C*catégories tensorielles, qui sont les catégories de bimodules d'un facteur II_{1}"
at Institut de Mathématiques de Jussieu, Paris, France, in the operator algebras seminar.

April 2012
"Tensor C*categories arising as bimodule categories of II_{1} factors"
at KU Leuven, Belgium, in the operator algebras seminar.

June 2009
"On the corepresentation theory of complexified quantum groups"
at KU Leuven, Belgium, in the operator algebras seminar.
Teaching and supervision
Taught courses
Supervision of PhD students
Supervision of Master theses
2017/18 
On groups of type I 
2016/17 
C*simplicity and factorial group von Neumann algebras 
2011/12 
Equivalence relations with prescribed fundamental group (cosupervision) 
2010/11 
Orbit equivalence of Bernoulli actions over free groups (cosupervision) 
2009/10 
There is no universal II_{1} factor (cosupervision) 
Supersion of Bachelor theses
2021/22

The search for orthogonal Latin squares (teacher student)
Measuretheoretic Probability

2020/21

Decomposition theory for zerosum games (matheconomy student)
Mathematical billards (teacher student)
The logic behind Kőnig's lemma
Quivers, path algebras and Gabriel's theorem
Which schools would take me? Truthtelling in school choice with admission probability uncertainty

2019/20

Quantum computing: From Shor’s algorithm to the hidden subgroup problem
The travelling salesman in Sweden (teacher student)
Classical finite simple groups
The spectral theorem for normal operators

2018/19

Wallpaper groups (teacher student)

2017/18

Ktheory and Bott periodicity

2016/17

Classification of closed surfaces

Teaching material
Lie groups. Spring term 2018
Homology and Cohomology. Spring term 2018
Abstract harmonic analysis. Spring term 2017
Abstrakte harmonische Analysis. Sommersemester 2016
Von Neumann Algebren und messbare Gruppentheorie. Wintersemester 2015/16
Vita
Born on 9th April 1985 in Kassel, Germany.
Current Employment
Since Sep 2018 
Associate Professor at Stockholm University, Sweden 
Previous Employment
Jun  Jul 2021 
Visiting Professor at IM PAN, Poland 
Sep  Dec 2020 
Visiting Professor at IM PAN, Poland 
2016  2018 
Lecturer at EPFL, Switzerland 
2015  2016 
Marie Curie International Outgoing Fellow at the University of Münster, Germany 
2014  2015 
Marie Curie International Outgoing Fellow at RIMS, Kyoto, Japan 
2013  2014 
Post doctoral scholar at ENS Lyon, France 
2009  2013 
PhD scholar at KU Leuven, Belgium 
2007  2009 
Student teaching assistant at the University of Münster 
Education
Oct 2019 
Docent in Mathematics at Stockholm University, Sweden 
Sep 2009  Jun 2013 
PhD in Mathematics at KU Leuven, Belgium 
Oct 2005  May 2009 
Diplom Mathematik at the University of Münster, Germany 
Languages
German 
Mother tongue 
English 
Fluent 
French 
Fluent (B2) 
Dutch 
Fluent (C1) 
Swedish 
Good 
Japanese 
Baisc knowledge (JLPT N5) 
Persian 
Basic knowledge 