WebThe notions of Borel equivalence relation and Borel reduction can then be de ned just as above in this more general setting. By a classical result ... Borel equivalence relation E on the standard Borel space X there is a countable group Gand a Borel action Gy X such that E = EX G. In this sense the study of countable http://logic.fudan.edu.cn/doc/Event/2016/2016CMLC/s_dly.pdf
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WebThis equivalence relation is denoted by EX G,ρ, or just E X G if the action is clear from the context. Here are some examples of equivalence relations induced by a Borel action: • id the identity relation. • id+ the jump of identity. This is an equivalence relation on (2 κ) where (xα)α WebReduction of Borel equivalence relations to Borel ideals. Appendix A. On Cohen and Gandy–Harrington forcing over countable models. Additional Material . Introduction. ... イベントレジスト 株
Borel Equivalence Relations : Structure and Classification - Google …
Webeach B 2B. A Borel isomorphism between X,Y is a bijection f : X !Y such that both f, f 1 are Borel. The following is a consequence of a deep result in descriptive set theory known as Souslin’s theorem. Theorem 1.11. If X,Y are standard Borel spaces and f : X !Y, then the following are equivalent: (1) f is Borel; (2)Graph(f) X Y is a Borel set. Weban increasing sequence of finite Borel equivalence relations. • Equivalently, a hyperfinite equivalence relation is one that is induced by a Z-action. • Slaman-Steel [1988]: Turing equivalence is not hyperfinite. • Corollary: No countable Borel equivalence relation coarser than 1-equivalence is hyperfinite. Proof: Use X ≡ WebAbstract. We present some natural examples of countable Borel equivalence relations E, F with E ≤ B F such that there does not exist a continuous reduction from E to F. 1. Introduction If E, E 0are Borel equivalence relations on the standard Borel spaces X, X, then Eis said to be Borel reducible to E0, written E≤ B E0, if there exists a Borel イベントレジスト 会員登録