Non-orbit equivalent actions of 𝔽 n

Adrian Ioana

Annales scientifiques de l'École Normale Supérieure (2009)

  • Volume: 42, Issue: 4, page 675-696
  • ISSN: 0012-9593

Abstract

top
For any 2 n , we construct a concrete 1-parameter family of non-orbit equivalent actions of the free group 𝔽 n . These actions arise as diagonal products between a generalized Bernoulli action and the action 𝔽 n ( 𝕋 2 , λ 2 ) , where 𝔽 n is seen as a subgroup of SL 2 ( ) .

How to cite

top

Ioana, Adrian. "Non-orbit equivalent actions of $\mathbb {F}_n$." Annales scientifiques de l'École Normale Supérieure 42.4 (2009): 675-696. <http://eudml.org/doc/272249>.

@article{Ioana2009,
abstract = {For any $2\le n\le \infty $, we construct a concrete 1-parameter family of non-orbit equivalent actions of the free group $\mathbb \{F\}_n$. These actions arise as diagonal products between a generalized Bernoulli action and the action $\mathbb \{F\}_n\curvearrowright (\mathbb \{T\}^2,\lambda ^2)$, where $\mathbb \{F\}_n$ is seen as a subgroup of $\mathrm \{SL\}_2(\mathbb \{Z\})$.},
author = {Ioana, Adrian},
journal = {Annales scientifiques de l'École Normale Supérieure},
keywords = {free groups; orbit equivalence},
language = {eng},
number = {4},
pages = {675-696},
publisher = {Société mathématique de France},
title = {Non-orbit equivalent actions of $\mathbb \{F\}_n$},
url = {http://eudml.org/doc/272249},
volume = {42},
year = {2009},
}

TY - JOUR
AU - Ioana, Adrian
TI - Non-orbit equivalent actions of $\mathbb {F}_n$
JO - Annales scientifiques de l'École Normale Supérieure
PY - 2009
PB - Société mathématique de France
VL - 42
IS - 4
SP - 675
EP - 696
AB - For any $2\le n\le \infty $, we construct a concrete 1-parameter family of non-orbit equivalent actions of the free group $\mathbb {F}_n$. These actions arise as diagonal products between a generalized Bernoulli action and the action $\mathbb {F}_n\curvearrowright (\mathbb {T}^2,\lambda ^2)$, where $\mathbb {F}_n$ is seen as a subgroup of $\mathrm {SL}_2(\mathbb {Z})$.
LA - eng
KW - free groups; orbit equivalence
UR - http://eudml.org/doc/272249
ER -

References

top
  1. [1] S. I. Bezuglyĭ & V. Y. Golodets, Hyperfinite and II 1 actions for nonamenable groups, J. Funct. Anal.40 (1981), 30–44. Zbl0496.22011MR607589
  2. [2] M. Burger, Kazhdan constants for SL ( 3 , 𝐙 ) , J. reine angew. Math. 413 (1991), 36–67. Zbl0704.22009MR1089795
  3. [3] A. Connes, J. Feldman & B. Weiss, An amenable equivalence relation is generated by a single transformation, Ergodic Theory Dynam. Systems1 (1981), 431–450. Zbl0491.28018MR662736
  4. [4] A. Connes & B. Weiss, Property T and asymptotically invariant sequences, Israel J. Math.37 (1980), 209–210. Zbl0479.28017MR599455
  5. [5] H. A. Dye, On groups of measure preserving transformation. I, Amer. J. Math. 81 (1959), 119–159. Zbl0087.11501MR131516
  6. [6] I. Epstein, Orbit inequivalent actions of non-amenable groups, preprint arXiv:0707.4215, 2007. 
  7. [7] J. Feldman & C. C. Moore, Ergodic equivalence relations, cohomology, and von Neumann algebras. II, Trans. Amer. Math. Soc. 234 (1977), 325–359. Zbl0369.22010MR578730
  8. [8] D. Gaboriau, On orbit equivalence of measure preserving actions, in Rigidity in dynamics and geometry (Cambridge, 2000), Springer, 2002, 167–186. Zbl1036.22008MR1919400
  9. [9] D. Gaboriau, Relative property ( T ) actions and trivial outer automorphism groups, preprint arXiv:0804.0358, 2008. Zbl1211.46071
  10. [10] D. Gaboriau & R. Lyons, A measurable-group-theoretic solution to von Neumann’s problem, Invent. Math.177 (2009), 533–540. Zbl1182.43002MR2534099
  11. [11] D. Gaboriau & S. Popa, An uncountable family of nonorbit equivalent actions of 𝔽 n , J. Amer. Math. Soc.18 (2005), 547–559. Zbl1155.37302MR2138136
  12. [12] S. L. Gefter & V. Y. Golodets, Fundamental groups for ergodic actions and actions with unit fundamental groups, Publ. Res. Inst. Math. Sci.24 (1988), 821–847. Zbl0684.22003MR1000122
  13. [13] G. Hjorth, A converse to Dye’s theorem, Trans. Amer. Math. Soc.357 (2005), 3083–3103. Zbl1068.03035MR2135736
  14. [14] A. Ioana, Orbit inequivalent actions for groups containing a copy of 𝔽 2 , preprint arXiv:math/0701027, 2007. Zbl1230.37010MR2810796
  15. [15] A. Ioana, A relative version of Connes’ χ ( M ) invariant and existence of orbit inequivalent actions, Ergodic Theory Dynam. Systems27 (2007), 1199–1213. Zbl1121.37006MR2342972
  16. [16] A. Ioana, Rigidity results for wreath product II 1 factors, J. Funct. Anal.252 (2007), 763–791. Zbl1134.46041MR2360936
  17. [17] A. Ioana, J. Peterson & S. Popa, Amalgamated free products of weakly rigid factors and calculation of their symmetry groups, Acta Math.200 (2008), 85–153. Zbl1149.46047MR2386109
  18. [18] V. F. R. Jones & K. Schmidt, Asymptotically invariant sequences and approximate finiteness, Amer. J. Math.109 (1987), 91–114. Zbl0638.28014MR878200
  19. [19] Y. Kida, Classification of certain generalized Bernoulli actions of mapping class groups, preprint http://www.math.kyoto-u.ac.jp/~kida/papers/ber.pdf, 2008. 
  20. [20] N. Monod & Y. Shalom, Orbit equivalence rigidity and bounded cohomology, Ann. of Math.164 (2006), 825–878. Zbl1129.37003MR2259246
  21. [21] F. J. Murray & J. Von Neumann, On rings of operators, Ann. of Math.37 (1936), 116–229. Zbl0014.16101MR1503275
  22. [22] D. S. Ornstein & B. Weiss, Ergodic theory of amenable group actions. I. The Rohlin lemma, Bull. Amer. Math. Soc. (N.S.) 2 (1980), 161–164. Zbl0427.28018MR551753
  23. [23] D. S. Ornstein & B. Weiss, Entropy and isomorphism theorems for actions of amenable groups, J. Analyse Math.48 (1987), 1–141. Zbl0637.28015MR910005
  24. [24] K. Petersen, Ergodic theory, Cambridge Studies in Advanced Math. 2, Cambridge Univ. Press, 1983. Zbl0507.28010MR833286
  25. [25] S. Popa, On a class of type II 1 factors with Betti numbers invariants, Ann. of Math.163 (2006), 809–899. Zbl1120.46045MR2215135
  26. [26] S. Popa, Some computations of 1-cohomology groups and construction of non-orbit-equivalent actions, J. Inst. Math. Jussieu5 (2006), 309–332. Zbl1092.37003MR2225044
  27. [27] S. Popa, Strong rigidity of II 1 factors arising from malleable actions of w -rigid groups. I, Invent. Math. 165 (2006), 369–408. Zbl1120.46043MR2231961
  28. [28] S. Popa, Cocycle and orbit equivalence superrigidity for malleable actions of w -rigid groups, Invent. Math.170 (2007), 243–295. Zbl1131.46040MR2342637
  29. [29] S. Popa, Deformation and rigidity for group actions and von Neumann algebras, in International Congress of Mathematicians. Vol. I, Eur. Math. Soc., Zürich, 2007, 445–477. Zbl1132.46038MR2334200
  30. [30] S. Popa, On the superrigidity of malleable actions with spectral gap, J. Amer. Math. Soc.21 (2008), 981–1000. Zbl1222.46048MR2425177
  31. [31] S. Popa & S. Vaes, Actions of 𝔽 whose II 1 factors and orbit equivalence relations have prescribed fundamental group, preprint arXiv:0803.3351, 2008, to appear in J. Amer. Math. Soc. Zbl1202.46069MR2601038
  32. [32] K. Schmidt, Amenability, Kazhdan’s property T , strong ergodicity and invariant means for ergodic group-actions, Ergodic Theory Dynam. Systems 1 (1981), 223–236. Zbl0485.28019MR661821
  33. [33] Y. Shalom, Measurable group theory, in European Congress of Mathematics, Eur. Math. Soc., Zürich, 2005, 391–423. Zbl1137.37301MR2185757
  34. [34] R. J. Zimmer, Ergodic theory and semisimple groups, Monographs in Math. 81, Birkhäuser, 1984. Zbl0571.58015MR776417

NotesEmbed ?

top

You must be logged in to post comments.

To embed these notes on your page include the following JavaScript code on your page where you want the notes to appear.

Only the controls for the widget will be shown in your chosen language. Notes will be shown in their authored language.

Tells the widget how many notes to show per page. You can cycle through additional notes using the next and previous controls.

    
                

Note: Best practice suggests putting the JavaScript code just before the closing </body> tag.