Abstract
We show that Katětov and Rudin-Blass orders on summable tall ideals coincide. We prove that Katětov order on summable tall ideals is Galois-Tukey equivalent to (ωω, ≤∗). It follows that Katětov order on summable tall ideals is upwards directed which answers a question of H. Minami and H. Sakai. In addition, we prove that l∞ is Borel bireducible to an equivalence relation induced by Katětov order on summable tall ideals.
Original language | English |
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Journal | Journal of Symbolic Logic |
DOIs | |
State | Accepted/In press - 2023 |
Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2023 Cambridge University Press. All rights reserved.
Keywords
- Galois-Tukey connection
- Katětov order
- Summable ideal