Abstract
A generic extension \({\mathbf{L}[x]}\) by a real x is defined, in which the \({\mathsf{E}_0}\)-class of x is a lightface \({{\it \Pi}^1_2}\) (hence, ordinal-definable) set containing no ordinal-definable reals.
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References
Enayat A.: On the Leibniz-Mycielski axiom in set theory. Fundam. Math. 181(3), 215–231 (2004)
Friedman, Sy D.: The \({\Pi^1_2}\) -singleton conjecture. J. Am. Math. Soc. 3(4), 771–791 (1990)
Groszek M., Laver R.: Finite groups of OD-conjugates. Period. Math. Hung. 18, 87–97 (1987)
Harrington L.A., Kechris A.S., Louveau A.: A Glimm-Effros dichotomy for Borel equivalence relations. J. Am. Math. Soc. 3(4), 903–928 (1990)
Jech T.: Set Theory, the Third Millennium Revised and Expanded Edition. Springer, Berlin (2003)
Jensen, R.: Definable sets of minimal degree. In: Mathematical Logic and Foundations of Set Theory, Proceedings of an International Colloquium, Jerusalem, 1968, pp. 122–128 (1970)
Kanovei, V., Lyubetsky, V.: A countable definable set of reals containing no definable elements. ArXiv e-prints, arXiv:1408.3901 (2014)
Kanovei, V.: Borel Equivalence Relations. Structure and Classification. AMS, Providence, RI (2008)
Kanovei V., Sabok M., Zapletal J.: Canonical Ramsey theory on Polish Spaces. Cambridge University Press, Cambridge (2013)
Kechris, A., Woodin, W.: On thin \({\Pi^1_2}\) sets. Handwritten note (1983), cited in [2]
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The work of Vladimir Kanovei was supported by RFFI Grant 13-01-00006.
The work of Vassily Lyubetsky was supported by the Russian Scientific Fund (Grant No. 14-50-00150).
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Kanovei, V., Lyubetsky, V. A definable E 0 class containing no definable elements. Arch. Math. Logic 54, 711–723 (2015). https://doi.org/10.1007/s00153-015-0436-9
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DOI: https://doi.org/10.1007/s00153-015-0436-9