Abstract
Burgess-Mauldin have proven the Ramsey-theoretic result that continuous sequences \({\left( {{\mu _c}} \right)_{c \in {2^\mathbb{N}}}}\) of pairwise orthogonal Borel probability measures admit continuous orthogonal subsequences. We establish an analogous result for sequences indexed by 2N/E0, the next Borel cardinal. As a corollary, we obtain a strengthening of the Harrington-Kechris-Louveau E0 dichotomy for restrictions of measure equivalence. We then use this to characterize the family of countable Borel equivalence relations which are non-hyperfinite with respect to an ergodic Borel probability measure which is not strongly ergodic.
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The first author was supported in part by NSF Grant DMS-1500906.
The second author was supported in part by FWF Grant P28153 and SFB Grant 878.
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Conley, C.T., Miller, B.D. Orthogonal measures and ergodicity. Isr. J. Math. 218, 83–99 (2017). https://doi.org/10.1007/s11856-017-1460-8
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DOI: https://doi.org/10.1007/s11856-017-1460-8