Ukrainian Mathematical Journal

, Volume 67, Issue 12, pp 1922–1931 | Cite as

Ultrafilters on Balleans

  • I. V. Protasov
  • S. V. Slobodianiuk

A ballean (or, equivalently, a coarse structure) is an asymptotic counterpart of a uniform space. We introduce three ultrafilter satellites of a ballean (namely, corona, companion, and corona companion), estimate the basic cardinal invariants of the corona, and characterize the subsets of balleans in terms of companions.


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Copyright information

© Springer Science+Business Media New York 2016

Authors and Affiliations

  • I. V. Protasov
    • 1
  • S. V. Slobodianiuk
    • 1
  1. 1.Shevchenko Kyiv National UniversityKyivUkraine

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