Abstract
We show that if \(\mathcal{T} \) is any Hausdorff topology on \(\omega_{1} \), then any subset of \(\omega_{1} \) which is homeomorphic to the rationals under \(\mathcal{T} \) can be refined to a homeomorphic copy of the rationals on which \(\bar{\rho}\) is shift-increasing
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This paper was completed when the first author was a Fields Research Fellow. The first author thanks the Fields Institute for its kind hospitality.
Second author is partially supported by grants from NSERC (455916) and CNRS (IMJ-PRGUMR7586).
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Raghavan, D., Todorcevic, S. A combinatorial property of rho-functions. Acta Math. Hungar. 167, 355–363 (2022). https://doi.org/10.1007/s10474-022-01237-y
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DOI: https://doi.org/10.1007/s10474-022-01237-y