Publications Stefaan Vaes

• Factoriality of twisted locally compact group von Neumann algebras. Preprint

• W*-superrigidity for groups with infinite center. With Milan Donvil. Preprint

• Borel fields and measured fields of Polish spaces, Banach spaces, von Neumann algebras and C*-algebras. With Lise Wouters. Preprint

Research articles

• Every locally compact group is the outer automorphism group of a II_1 factor. To appear in Proceedings of the Royal Society of Edinburgh, Section A: Mathematics. Download

• W*-superrigidity for cocycle twisted group von Neumann algebras. With Milan Donvil. Inventiones Mathematicae 240 (2025), 193-260. Download

• Ergodic states on type III_1 factors and ergodic actions. With Amine Marrakchi. Journal für die Reine und Angewandte Mathematik 809 (2024), 247-260. Download

• Measure equivalence embeddings of free groups and free group factors. With Tey Berendschot. To appear in Annales Scientifiques de l'Ecole Normale Supérieure. Download

• Quantum automorphism groups of connected locally finite graphs and quantizations of discrete groups. With Lukas Rollier. International Mathematics Research Notices (IMRN) 3 (2024), 2219-2297. Download

• Orbit equivalence superrigidity for type III_0 actions. With Bram Verjans. Ergodic Theory and Dynamical Systems 43 (2023), 4193-4225. Download

• Classification results for nonsingular Bernoulli crossed products. With Bram Verjans. Studia Mathematica 268 (2023), 91-120. Download

• Spectral gap and strict outerness for actions of locally compact groups on full factors. With Amine Marrakchi. Enseignement Mathématique 69 (2023), 353-379. Special issue in honor of Vaughan F. R. Jones. Download

• Superrigidity for dense subgroups of Lie groups and their actions on homogeneous spaces. With Daniel Drimbe. Mathematische Annalen 386 (2023), 2015-2059. Download

• Bernoulli actions of type III_0 with prescribed associated flow. With Tey Berendschot. Journal of the Institute of Mathematics of Jussieu 23 (2024), 71-122. Download

• KMS spectra for group actions on compact spaces. With Johannes Christensen. Communications in Mathematical Physics 390 (2022), 1341-1367. Download

• W*-rigidity paradigms for embeddings of II_1 factors. With Sorin Popa. Communications in Mathematical Physics 395 (2022), 907-961. Download

• Nonsingular Gaussian actions: beyond the mixing case. With Amine Marrakchi. Advances in Mathematics 397 (2022), paper no. 108190. Download

• Nonsingular Bernoulli actions of arbitrary Krieger type. With Tey Berendschot. Analysis and PDE 15 (2022), 1313-1373. Download

• Ergodicity and type of nonsingular Bernoulli actions. With Michael Björklund and Zemer Kosloff. Inventiones Mathematicae 224 (2021), 573-625. Download

• Classification of regular subalgebras of the hyperfinite II_1 factor. With Sorin Popa and Dimitri Shlyakhtenko. Journal de Mathématiques Pures et Appliquées 140 (2020), 280-308. Download

• Property (T) discrete quantum groups and subfactors with triangle presentations. With Matthias Valvekens. Advances in Mathematics 345 (2019), 382-428. Download

• Non-classification of free Araki-Woods factors and tau-invariants. With Román Sasyk and Asger Törnquist. Groups, Geometry, and Dynamics 13 (2019), 1219-1234. Download

• Bernoulli actions of type III_1 and L^2-cohomology. With Jonas Wahl. Geometric and Functional Analysis (GAFA) 28 (2018), 518-562. Download

• Rigidity for von Neumann algebras given by locally compact groups and their crossed products. With Arnaud Brothier and Tobe Deprez. Communications in Mathematical Physics 361 (2018), 81-125. Download

• L^2-Betti numbers of rigid C*-tensor categories and discrete quantum groups. With David Kyed, Sven Raum and Matthias Valvekens. Analysis and PDE 10 (2017), 1757-1791. Download

• Thin II_1 factors with no Cartan subalgebras. With Anna Sofie Krogager. Kyoto Journal of Mathematics 59 (2019), 815-867. Download

• Classification of a family of non almost periodic free Araki-Woods factors. With Cyril Houdayer and Dimitri Shlyakhtenko. Journal of the European Mathematical Society 21 (2019), 3113-3142. Download

• Inner amenability, property Gamma, McDuff II_1 factors and stable equivalence relations. With Tobe Deprez. Ergodic Theory and Dynamical Systems 38 (2018), 2618-2624. Download

• C*-tensor categories and subfactors for totally disconnected groups. With Yuki Arano. In Operator Algebras and Applications, The Abel Symposium 2015, Springer, 2016, pp. 1-43. Download

• A class of II_1 factors with exactly two group measure space decompositions. With Anna Sofie Krogager. Journal de Mathématiques Pures et Appliquées 108 (2017), 88-110. Download

• Strong solidity of free Araki-Woods factors. With Rémi Boutonnet and Cyril Houdayer. American Journal of Mathematics 140 (2018), 1231-1252. Download

• Cohomology and L^2-Betti numbers for subfactors and quasi-regular inclusions. With Sorin Popa and Dimitri Shlyakhtenko. International Mathematics Research Notices, volume 2018, issue 8 (2018), 2241-2331. Download

• On the optimal paving over MASAs in von Neumann algebras. With Sorin Popa. In Operator Algebras and Their Applications: A Tribute to Richard V. Kadison, Contemporary Mathematics 671 (2016), 199-208. Download

• Representation theory for subfactors, lambda-lattices and C*-tensor categories. With Sorin Popa. Communications in Mathematical Physics 340 (2015), 1239-1280. Download

• Paving over arbitrary MASAs in von Neumann algebras. With Sorin Popa. Analysis and PDE 8 (2015), 1001-1023. Download

• Classification of type III Bernoulli crossed products. With Peter Verraedt. Advances in Mathematics 281 (2015), 296-332. Download

• Spectral gap for inclusions of von Neumann algebras. With Adrian Ioana. Appendix to the article Cartan subalgebras of amalgamated free product II_1 factors by Adrian Ioana. Annales Scientifiques de l'Ecole Normale Supérieure 48 (2015), 71-130. Download

• Vanishing of the first continuous L^2-cohomology for II_1 factors. With Sorin Popa. International Mathematics Research Notices (2014), article id: rnu054. Download

• Families of hyperfinite subfactors with the same standard invariant and prescribed fundamental group. With Arnaud Brothier. Journal of Noncommutative Geometry 9 (2015), 775-796. Download

• Normalizers inside amalgamated free product von Neumann algebras. Publications of the Research Institute for Mathematical Sciences 50 (2014), 695–721. Download

• L^2-Betti numbers of locally compact groups and their cross section equivalence relations. With David Kyed and Henrik Densing Petersen. Transactions of the American Mathematical Society 367 (2015), 4917-4956. Download

• Partial classification of the Baumslag-Solitar group von Neumann algebras. With Niels Meesschaert. Documenta Mathematica 19 (2014), 629-645. Download

• W*-superrigidity for group von Neumann algebras of left-right wreath products. With Mihaita Berbec. Proceedings of the London Mathematical Society 108 (2014), 1116-1152. Download

• Type III factors with a unique Cartan decomposition. With Cyril Houdayer. Journal de Mathématiques Pures et Appliquées 100 (2013), 564-590. Download

• Unique Cartan decomposition for II_1 factors arising from arbitrary actions of hyperbolic groups. With Sorin Popa. Journal für die reine und angewandte Mathematik 694 (2014), 215-239. Download

• Unique Cartan decomposition for II_1 factors arising from arbitrary actions of free groups. With Sorin Popa. Acta Mathematica 212 (2014), 141-198. Download

• Stable orbit equivalence of Bernoulli actions of free groups and isomorphism of some of their factor actions. With Niels Meesschaert and Sven Raum. Expositiones Mathematicae 31 (2013), 274-294. Download

• A class of II_1 factors with many non conjugate Cartan subalgebras. With An Speelman. Advances in Mathematics 231 (2012), 2224-2251. Download

• One-cohomology and the uniqueness of the group measure space decomposition of a II_1 factor. Mathematische Annalen 355 (2013), 661-696. Download

• A class of groups for which every action is W*-superrigid. With Cyril Houdayer and Sorin Popa. Groups, Geometry, and Dynamics 7 (2013), 577-590. Download

• Rigidity for von Neumann algebras and their invariants. In Proceedings of the International Congress of Mathematicians (Hyderabad, India, 2010), Vol. III, Hindustan Book Agency, 2010, pp. 1624-1650. Download

• A class of superrigid group von Neumann algebras. With Adrian Ioana and Sorin Popa. Annals of Mathematics 178 (2013), 231-286. Download

• Rigid actions need not be strongly ergodic. With Adrian Ioana. Proceedings of the American Mathematical Society 140 (2012), 3283-3288. Download

• HNN extensions and unique group measure space decomposition of II_1 factors. With Pierre Fima. Transactions of the American Mathematical Society 364 (2012), 2601-2617. Download

• A classification of all finite index subfactors for a class of group-measure space II_1 factors. With Steven Deprez. Journal of Noncommutative Geometry 5 (2011), 523-545. Download

• An inner amenable group whose von Neumann algebra does not have property Gamma. Acta Mathematica 208 (2012), 389-394. Download

• Group measure space decomposition of II_1 factors and W*-superrigidity. With Sorin Popa. Inventiones Mathematicae 182 (2010), 371-417. Download

• Poisson boundary of the discrete quantum group A_u(F)^. With Nikolas Vander Vennet. Compositio Mathematica 146 (2010), 1073-1095. Download

• The representation category of any compact group is the bimodule category of a II_1 factor. With Sébastien Falguières. Journal für die reine und angewandte Mathematik 643 (2010), 171-199. Download

• Cocycle and orbit superrigidity for lattices in SL(n,R) acting on homogeneous spaces. With Sorin Popa. In Geometry, rigidity and group actions, Eds. B. Farb and D. Fisher. The University of Chicago Press, 2011, pp. 419-451. Download

• On the fundamental group of II_1 factors and equivalence relations arising from group actions. With Sorin Popa. In Quanta of Maths, Proceedings of the Conference in honor of A.Connes' 60th birthday, Clay Mathematics Institute Proceedings 11 (2011), pp. 519-541. Download

• Actions of F_\infty whose II_1 factors and orbit equivalence relations have prescribed fundamental group. With Sorin Popa. Journal of the American Mathematical Society 23 (2010), 383-403. Download

• Explicit computations of all finite index bimodules for a family of II_1 factors. Annales Scientifiques de l'Ecole Normale Supérieure 41 (2008), 743-788. Download

• Every compact group arises as the outer automorphism group of a II_1 factor. With Sébastien Falguières. Journal of Functional Analysis 254 (2008), 2317-2328. Download

• Factors of type II_1 without non-trivial finite index subfactors. Transactions of the American Mathematical Society 361 (2009), 2587-2606. Download

• Identification of the Poisson and Martin boundaries of orthogonal discrete quantum groups. With Nikolas Vander Vennet. Journal of the Institute of Mathematics of Jussieu 7 (2008), 391-412. Download

• Strong rigidity of generalized Bernoulli actions and computations of their symmetry groups. With Sorin Popa. Advances in Mathematics 217 (2008), 833-872. Download

• Rigidity results for Bernoulli actions and their von Neumann algebras (after Sorin Popa). Séminaire Bourbaki, exposé 961. Astérisque 311 (2007), 237-294. Download

• The boundary of universal discrete quantum groups, exactness and factoriality. With Roland Vergnioux. Duke Mathematical Journal 140 (2007), 35-84. Download

• Ergodic coactions with large multiplicity and monoidal equivalence of quantum groups. With Julien Bichon and An De Rijdt. Communications in Mathematical Physics 262 (2006), 703-728. Download

• États quasi-libres libres et facteurs de type III (d'après D. Shlyakhtenko). Séminaire Bourbaki, exposé 937, Astérisque 299 (2005), 329-350. Download

• A new approach to induction and imprimitivity results. Journal of Functional Analysis 229 (2005), 317-374. Download

• Measurable Kac cohomology for bicrossed products. With Saad Baaj and Georges Skandalis. Transactions of the American Mathematical Society 357 (2005), 1497-1524. Download

• Strictly outer actions of groups and quantum groups. Journal für die reine und angewandte Mathematik 578 (2005), 147-184. Download

• Double crossed products of locally compact quantum groups. With Saad Baaj. Journal of the Institute of Mathematics of Jussieu 4 (2005), 135-173. Download

• Non-semi-regular quantum groups coming from number theory. With Saad Baaj and Georges Skandalis. Communications in Mathematical Physics 235 (2003), 139-167. Download

• On low-dimensional locally compact quantum groups. With Leonid Vainerman. Locally Compact Quantum Groups and Groupoids. Proceedings of the Meeting of Theoretical Physicists and Mathematicians, Strasbourg, February 21 - 23, 2002, Ed. L. Vainerman, IRMA Lectures on Mathematics and Mathematical Physics, Walter de Gruyter, Berlin, New York (2003), pp. 127-187. Download

• Amenability and the bicrossed product construction. With Pieter Desmedt and Johan Quaegebeur. Illinois Journal of Mathematics 46 (2002), 1259-1277. Download

• Extensions of locally compact quantum groups and the bicrossed product construction. With Leonid Vainerman. Advances in Mathematics 175 (1) (2003), 1-101. Download

• The unitary implementation of a locally compact quantum group action. Journal of Functional Analysis 180 (2001), 426-480. Download

• Locally compact quantum groups. With Johan Kustermans. Annales Scientifiques de l'Ecole Normale Supérieure 33 (2000), 837-934. Download

• The operator algebra approach to quantum groups. With Johan Kustermans. Proceedings of the National Academy of Sciences USA 97 (2000), 547-552. Download

• Locally compact quantum groups in the von Neumann algebraic setting. With Johan Kustermans. Mathematica Scandinavica 92 (2003), 68-92. Download

• A simple definition for locally compact quantum groups. With Johan Kustermans. Comptes Rendus de l'Académie des Sciences, Paris. Série I 328 (1999), 871-876. Download

• Hopf C*-algebras. With Alfons Van Daele. Proceedings of the London Mathematical Society 82 (2001), 337-384. Download

• A Radon-Nikodym theorem for von Neumann algebras. Journal of Operator Theory 46 (2001), 477-489. Download

Oberwolfach reports

• Classification of crossed product II_1 factors and group-type subfactors. In C*-algebras, Oberwolfach Reports 10 (2013), 2491-2493. Download

• A class of group factors L(G) that remember the group G (joint work with Adrian Ioana and Sorin Popa). In C*-algebras, Oberwolfach Reports 7 (2010), 673-675. Download

• Superrigid actions of lattices in SL(n,R) on homogeneous spaces (joint work with Sorin Popa). In Von Neumann algebras and ergodic theory of group actions, Oberwolfach Reports 5 (2008), 2808-2810. Download

• Fundamental groups of II_1 factors and equivalence relations (joint work with Sorin Popa). In C*-algebras, Oberwolfach Reports 5 (2008), 2114-2115. Download

• Boundaries and exactness for discrete quantum groups. In C*-Algebren, Oberwolfach Reports 2 (2005), 2309-2311. Download

• Induction of C*-algebra coactions. In Nichtkommutative Geometrie, Oberwolfach Reports 1 (2004), 2404-2409. Download

Surveys and conference proceedings

• Amenability versus non amenability: an introduction to von Neumann algebras. In European Congress of Mathematics, Berlin 2016, Eur. Math. Soc., Zürich, 2018, pp. 483-500. Download

• Examples of locally compact quantum groups through the bicrossed product construction. In Proceedings of the XIIIth International Congress of Mathematical Physics, Imperial College, London, 2000. Editors A. Grigoryan, A. Fokas, T. Kibble and B. Zegarlinski, International Press of Boston, Somerville MA (2001), pp. 341-348. Download

• The Heisenberg commutation relations, commuting squares and the Haar measure on locally compact quantum groups. With Alfons Van Daele. In Operator algebras and mathematical physics: conference proceedings, Constanta (Romania), July 2-7, 2001. Editors J.-M. Combes, J. Cuntz, G.A. Elliott, G. Nenciu, H. Siedentop and S. Stratila. Theta Foundation, Bucarest (2003), pp. 379-400. Download

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