On skew ultralimits and their applications in ultrafilter theory
Abstract
We define a special version of the ultralimit, called the skewed ultralimit. Using this tool, we show that the set of ultrafilter types in the C-equivalence class of a Ramsey ultrafilter u∈ βω with the Rudin-Keisler order is isomorphic to the ultrapower of (ω, ≤).
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