This paper studies structural consequences of supercompact- ness of ω1 under ZF. We show that the Axiom of Dependent Choice (DC) follows from “ω1 is supercompact”. “ω1 is supercompact” also implies that AD+, a strengthening of the Axiom of Determinacy (AD), is equiv- alent to ADR. It is shown that “ω1 is supercompact” does not imply AD. The most one can hope for is Suslin co-Suslin determinacy. We show that this follows from “ω1 is supercompact” and Hod Pair Capturing (HPC), an inner-model theoretic hypothesis that imposes certain smallness con- ditions on the universe of sets. “ω1 is supercompact” on its own implies that every Suslin co-Suslin set is the projection of a determined (in fact, homogenously Suslin) set. “ω1 is supercompact” also implies all sets in the Chang model have all the usual regularity properties, like Lebesgue measurability and the Baire property.
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Strong compactness and the ultrapower axiom I: the least strongly compact cardinal
The Ultrapower Axiom is a combinatorial principle concerning the structure of large cardinals that is true in all known canonical inner models of set theory. A longstanding test question for inner model theory is the equiconsistency of strongly compact and supercompact cardinals. In this paper, it is shown that under the Ultrapower Axiom, the least strongly compact cardinal is supercompact. A number of stronger results are established, setting the stage for a complete analysis of strong compactness and supercompactness under UA that will be carried out in the sequel to this paper.
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- Award ID(s):
- 1902884
- PAR ID:
- 10472497
- Publisher / Repository:
- World Scientific
- Date Published:
- Journal Name:
- Journal of Mathematical Logic
- Volume:
- 22
- Issue:
- 02
- ISSN:
- 0219-0613
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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