Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4661693 | Annals of Pure and Applied Logic | 2015 | 38 Pages |
Abstract
Let κ be a regular uncountable cardinal, and λ a cardinal greater than κ with cofinality less than κ. We consider a strengthening of the diamond principle âκ,λ that asserts that any subset of some fixed collection of λ+ elements of Pκ(λ) can be guessed on a stationary set. This new principle, denoted by âκ,λ[λ+], implies that the nonstationary ideal on Pκ(λ) is not 2(λ+)-saturated. We establish that if λ is large enough and there are no inner models with fairly large cardinals, then âκ,λ[λ+] holds. More precisely, it is shown that if 2(κâµ0)â¤Î»+ and both Shelah's Strong Hypothesis SSH and the Almost Disjoint Sets principle ADSλ hold, then âκ,λ[λ+] holds. The paper also contains ZFC results. Suppose for example that 2κâ¤Î»+, there is a strong limit cardinal Ï with cf(λ)<Ïâ¤Îº, and either κ is a successor cardinal greater than Ï+3, where Ï is the largest limit cardinal less than κ, or κ is a limit cardinal and Ïκ<λ<(Ïκ)+κ for some cardinal Ïâ¥2. Then âκ,λ[λ+] holds.
Related Topics
Physical Sciences and Engineering
Mathematics
Logic
Authors
Pierre Matet,