Local Clubs, Reflection, and Preserving Stationary Sets
نویسندگان
چکیده
We introduce the filter of locally closed unbounded sets and investigate its properties. As one application, we give a characterization of forcing notions that preserve stationary sets (in eo,). Also the local club filter and its variants lead to reflection principles for stationary sets. While the general reflection principle is related to Martin's Maximum of Foreman, Magidor and Shelah, the reflection at w2 is equiconsistent with a weakly compact cardinal.
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