Mathematical Research Letters
Volume 9, Issue 5, September 2002 pp. 585-595.
Duality and the pcf theoryAuthors: Saharon Shelah and Jindrich Zapletal
Author institution: Hebrew University, and University of Florida
Summary: We consider natural cardinal invariants $\hm_{\it n}$ and prove several duality theorems, saying roughly: if $I$ is a suitably definable ideal and provably $\cov(I)\geq\hm_{\it n}$, then $\non(I)$ is provably small. The proofs integrate the determinacy theory, forcing and pcf theory.
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