The orbit equivalence of type $III_{0}$ ergodic equivalence relations is considered. We show that it is equivalent to the outer conjugacy problem for the natural trace-scaling action of a countable dense ℝ-subgroup by automorphisms of the Radon-Nikodym skew product extensions of these relations. A similar result holds for the weak equivalence of arbitrary type $III_{0}$ cocycles with values in Abelian groups.
Graduate School of Mathematics, Kyushu University, Ropponmatsu Chuo-ku, Fukuoka, 810-8560, Japan
Bibliografia
[BG] S. I. Bezuglyi and V. Ya. Golodets, Weak equivalence and the structure of cocycles of an ergodic automorphism, Publ. RIMS Kyoto Univ. 27 (1991), 577-635.
[Da1] A. I. Danilenko, The topological structure of Polish groups and groupoids of measure space transformations, ibid. 31 (1995), 913-940.
[Da2] A. I. Danilenko, Quasinormal subrelations of ergodic equivalence relations, Proc. Amer. Math. Soc. 126 (1998), 3361-3370.
[FHM] J. Feldman, P. Hahn and C. C. Moore, Orbit structure and countable sections for actions of continuous groups, Adv. Math. 28 (1978), 186-230.
[FM] J. Feldman and C. C. Moore, Ergodic equivalence relations, cohomology, and von Neumann algebras I, Trans. Amer. Math. Soc. 234 (1977), 289-324.
[Go] V. Ya. Golodets, Description of representations of anticommutation relations, Uspekhi Mat. Nauk 24 (1969), no. 4, 3-64 (in Russian); English transl. in Russian Math. Surveys 24 (1969).
[GS] V. Ya. Golodets and S. D. Sinel'shchikov, Classification and structure of cocycles of amenable ergodic equivalence relations, J. Funct. Anal. 121 (1994), 455-485.
[Kr] W. Krieger, On ergodic flows and isomorphism of factors, Math. Ann. 223 (1976), 19-70.
[Mo] C. C. Moore, Ergodic theory and von Neumann algebras, in: Proc. Symp. Pure Math. 38, Part 2, Amer. Math. Soc., 1982, 179-226.
[Sc1] K. Schmidt, Cocycles of Ergodic Transformation Groups, Lecture Notes in Math. 1, MacMillan of India, Delhi, 1977.
[Sc2] K. Schmidt, Algebraic Ideas in Ergodic Theory, CBMS Regional Conf. Ser. in Math. 76, Amer. Math. Soc., Providence, RI, 1990.
[Ta] M. Takesaki, Duality for crossed product and the structure of von Neumann algebras of type III, Acta Math. 131 (1973), 249-310.
Typ dokumentu
Bibliografia
Identyfikatory
Identyfikator YADDA
bwmeta1.element.bwnjournal-article-cmv84i2p485bwm
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.