Abstract
We define the Haagerup property in the general context of countable groupoids equipped with a quasi-invariant measure. One of our objectives is to complete an article of Jolissaint devoted to the study of this property for probability measure preserving countable equivalence relations. Our second goal, concerning the general situation, is to provide a definition of this property in purely geometric terms, whereas this notion had been introduced by Ueda in terms of the associated inclusion of von Neumann algebras. Our equivalent definition makes obvious the fact that treeability implies the Haagerup property for such groupoids and that it is not compatible with Kazhdan’s property (T).
Mathematics Subject Classification (2010): 46L55, 37A15, 22A22, 20F65.
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Notes
- 1.
In [8], a countable measured groupoid is called r-discrete. !countable measured !discrete measured Another difference is that we have swapped here the definitions of ν and ν −1.
- 2.
When necessary, we shall write \(\hat{m}\) the element m ∈ M, when viewed in \({L}^{2}(M,\varphi )\), in order to stress this fact.
- 3.
In [25], \(\mathcal{K}(\left \langle M,e_{A}\right \rangle )\) is denoted \(\mathcal{I}_{0}(\left \langle M,e_{A}\right \rangle )\).
- 4.
The reader should not confuse L(f): L 2(G, ν) → L 2(G, ν) with its restriction \(L_{f}: {L}^{2}(A,\tau _{\mu }) \rightarrow {L}^{2}(G,\nu )\).
References
Adams, S.: Trees and amenable equivalence relations. Ergodic Theory Dynam. Systems 10(1), 1–14 (1990). DOI 10.1017/S0143385700005368. URL http://dx.doi.org/10.1017/S0143385700005368
Adams, S.R., Spatzier, R.J.: Kazhdan groups, cocycles and trees. Amer. J. Math. 112(2), 271–287 (1990). DOI 10.2307/2374716. URL http://dx.doi.org/10.2307/2374716
Akemann, C.A., Walter, M.E.: Unbounded negative definite functions. Canad. J. Math. 33(4), 862–871 (1981). DOI 10.4153/CJM-1981-067-9. URL http://dx.doi.org/10.4153/CJM-1981-067-9
Alvarez, A.: Une théorie de Bass-Serre pour les relations d’équivalence et les groupoïdes boréliens. Ph.D. thesis, Ecole Normale Supérieure de Lyon (2008). URL http://www.univ-orleans.fr/mapmo/membres/alvarez/MAPMO/accueil.html
Alvarez, A., Gaboriau, D.: Free products, orbit equivalence and measure equivalence rigidity. Groups Geom. Dyn. 6(1), 53–82 (2012). DOI 10.4171/GGD/150. URL http://dx.doi.org/10.4171/GGD/150
Anantharaman-Delaroche, C.: Cohomology of property T groupoids and applications. Ergodic Theory Dynam. Systems 25(4), 977–1013 (2005). DOI 10.1017/S0143385704000884. URL http://dx.doi.org/10.1017/S0143385704000884
Anantharaman-Delaroche, C.: Old and new about treeability and the Haagerup property for measured groupoids (2011), arXiv:1105.5961v1
Anantharaman-Delaroche, C., Renault, J.: Amenable groupoids, Monographies de L’Enseignement Mathématique [Monographs of L’Enseignement Mathématique], vol. 36. L’Enseignement Mathématique, Geneva (2000). With a foreword by Georges Skandalis and Appendix B by E. Germain
Boca, F.: On the method of constructing irreducible finite index subfactors of Popa. Pacific J. Math. 161(2), 201–231 (1993). URL http://projecteuclid.org/getRecord?id=euclid.pjm/1102623229
Cherix, P.A., Cowling, M., Jolissaint, P., Julg, P., Valette, A.: Groups with the Haagerup property. Gromov’s a-T-menability, Progress in Mathematics, vol. 197. Birkhäuser Verlag, Basel (2001). DOI 10.1007/978-3-0348-8237-8. URL http://dx.doi.org/10.1007/978-3-0348-8237-8
Choda, M.: Group factors of the Haagerup type. Proc. Japan Acad. Ser. A Math. Sci. 59(5), 174–177 (1983). URL http://projecteuclid.org/getRecord?id=euclid.pja/1195515589
Connes, A.: Classification des facteurs. In: Operator algebras and applications, Part 2 (Kingston, Ont., 1980), Proc. Sympos. Pure Math., vol. 38, pp. 43–109. Amer. Math. Soc., Providence, R.I. (1982)
Dixmier, J.: von Neumann algebras, North-Holland Mathematical Library, vol. 27. North-Holland Publishing Co., Amsterdam (1981). With a preface by E. C. Lance, Translated from the second French edition by F. Jellett
Feldman, J., Moore, C.C.: Ergodic equivalence relations, cohomology, and von Neumann algebras. I. Trans. Amer. Math. Soc. 234(2), 289–324 (1977)
Haagerup, U.: An example of a nonnuclear \({C}^{{\ast}}\)-algebra, which has the metric approximation property. Invent. Math. 50(3), 279–293 (1978/79). DOI 10.1007/BF01410082. URL http://dx.doi.org/10.1007/BF01410082
Hahn, P.: The regular representations of measure groupoids. Trans. Amer. Math. Soc. 242, 35–72 (1978). DOI 10.2307/1997727. URL http://dx.doi.org/10.2307/1997727
de la Harpe, P., Valette, A.: La propriété (T) de Kazhdan pour les groupes localement compacts (avec un appendice de Marc Burger). Astérisque (175), 158 (1989). With an appendix by M. Burger
Jolissaint, P.: The Haagerup property for measure-preserving standard equivalence relations. Ergodic Theory Dynam. Systems 25(1), 161–174 (2005). DOI 10.1017/S0143385704000562. URL http://dx.doi.org/10.1017/S0143385704000562
Jones, V.F.R.: Index for subfactors. Invent. Math. 72(1), 1–25 (1983). DOI 10.1007/BF01389127. URL http://dx.doi.org/10.1007/BF01389127
Kechris, A.S.: Classical descriptive set theory, Graduate Texts in Mathematics, vol. 156. Springer-Verlag, New York (1995). DOI 10.1007/978-1-4612-4190-4. URL http://dx.doi.org/10.1007/978-1-4612-4190-4
Kechris, A.S.: Global aspects of ergodic group actions, Mathematical Surveys and Monographs, vol. 160. American Mathematical Society, Providence, RI (2010)
Moore, C.C.: Virtual groups 45 years later. In: Group representations, ergodic theory, and mathematical physics: a tribute to George W. Mackey, Contemp. Math., vol. 449, pp. 263–300. Amer. Math. Soc., Providence, RI (2008). DOI 10.1090/conm/449/08716. URL http://dx.doi.org/10.1090/conm/449/08716
Paschke, W.L.: Inner product modules over \({B}^{{\ast}}\)-algebras. Trans. Amer. Math. Soc. 182, 443–468 (1973)
Popa, S.: Classification of subfactors and their endomorphisms, CBMS Regional Conference Series in Mathematics, vol. 86. Published for the Conference Board of the Mathematical Sciences, Washington, DC (1995)
Popa, S.: On a class of type II1 factors with Betti numbers invariants. Ann. of Math. (2) 163(3), 809–899 (2006). DOI 10.4007/annals.2006.163.809. URL http://dx.doi.org/10.4007/annals.2006.163.809
Popa, S., Rădulescu, F.: Derivations of von Neumann algebras into the compact ideal space of a semifinite algebra. Duke Math. J. 57(2), 485–518 (1988). DOI 10.1215/S0012-7094-88-05722-5. URL http://dx.doi.org/10.1215/S0012-7094-88-05722-5
Ramsay, A.: Virtual groups and group actions. Advances in Math. 6, 253–322 (1971) (1971)
Ramsay, A., Walter, M.E.: Fourier-Stieltjes algebras of locally compact groupoids. J. Funct. Anal. 148(2), 314–367 (1997). DOI 10.1006/jfan.1996.3083. URL http://dx.doi.org/10.1006/jfan.1996.3083
Renault, J.: A groupoid approach to \({C}^{{\ast}}\)-algebras, Lecture Notes in Mathematics, vol. 793. Springer, Berlin (1980)
Rieffel, M.A.: Morita equivalence for \({C}^{{\ast}}\)-algebras and \({W}^{{\ast}}\)-algebras. J. Pure Appl. Algebra 5, 51–96 (1974)
Takesaki, M.: Conditional expectations in von Neumann algebras. J. Functional Analysis 9, 306–321 (1972)
Ueda, Y.: Notes on treeability and costs for discrete groupoids in operator algebra framework. In: Operator Algebras: The Abel Symposium 2004, Abel Symp., vol. 1, pp. 259–279. Springer, Berlin (2006). DOI 10.1007/978-3-540-34197-0_13. URL http://dx.doi.org/10.1007/978-3-540-34197-0_13
Zimmer, R.J.: On the cohomology of ergodic actions of semisimple Lie groups and discrete subgroups. Amer. J. Math. 103(5), 937–951 (1981). DOI 10.2307/2374253. URL http://dx.doi.org/10.2307/2374253
Zimmer, R.J.: Ergodic theory and semisimple groups, Monographs in Mathematics, vol. 81. Birkhäuser Verlag, Basel (1984)
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Anantharaman-Delaroche, C. (2013). The Haagerup Property for Discrete Measured Groupoids. In: Carlsen, T., Eilers, S., Restorff, G., Silvestrov, S. (eds) Operator Algebra and Dynamics. Springer Proceedings in Mathematics & Statistics, vol 58. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-39459-1_1
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