Abstract
We compute the levels of complexity in analytical and arithmetical hierarchies for the sets of the Σ-formulas defining in the hereditarily finite superstructure over the ordered field of the reals the classes of open, closed, clopen, nowhere dense, dense subsets of ℝn, first category subsets in ℝn as well as the sets of pairs of Σ-formulas corresponding to the relations of set equality and inclusion which are defined by them. It is also shown that the complexity of the set of the Σ-formulas defining connected sets is at least Π 11 .
Similar content being viewed by others
References
Ershov Yu. L., Theory of Numberings [in Russian], Nauka, Moscow (1977).
Ershov Yu. L,, Definability and Computability, Plenum Publ. Co., New York (1996).
Barwise J., Admissible Sets and Structures, Springer-Verlag, Berlin; Göttingen; Heidelberg (1975).
Rogers H., Theory of Recursive Functions and Effective Computability, McGraw-Hill Book Comp., New York; St. Louis; San Francisco; Toronto; London; Sydney (1967).
Vaicenavicius R. Yu., “On the necessary conditions for the existence of a universal function on an admissible set,” Mat. Logika Primenen., No. 6, 21–37 (1989).
Author information
Authors and Affiliations
Corresponding author
Additional information
Original Russian Text Copyright © 2008 Morozov A. S.
The author was supported by the International Russian-German grant DFG-RFBR No. 06-01-04002-NNIOa, the Russian Foundation for Basic Research (Grant 08-01-00336-a), and the State Maintenance Program for the Leading Scientific Schools of the Russian Federation (Grant NSh-335.2008.1).
__________
Novosibirsk. Translated from Sibirskiĭ Matematicheskiĭ Zhurnal, Vol. 49, No. 6, pp. 1351–1360, November–December, 2008.
Rights and permissions
About this article
Cite this article
Morozov, A.S. On the index sets of Σ-subsets of the real numbers. Sib Math J 49, 1078–1084 (2008). https://doi.org/10.1007/s11202-008-0103-z
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11202-008-0103-z