Shelah's consistency conjecture for large sets of singular cardinals

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Let θ\theta be any uncountable cardinal. Shelah's consistency conjecture for pseudopowers. It is consistent that, for some cardinal λ\lambda, both of the following hold: (A) θ≤∣{μ<λ:cf⁡(μ)=ℵ0, pp⁡(μ)>λ}∣\theta\leq\left|\{\mu<\lambda:\operatorname{cf}(\mu)=\aleph_0,\ \operatorname{pp}(\mu)>\lambda\}\right|; and (B) for some λ\lambda, the set {μ<λ:cf⁡(μ)>ℵ0, pp⁡ℵ1–complete(μ)>λ}\{\mu<\lambda:\operatorname{cf}(\mu)>\aleph_0,\ \operatorname{pp}_{\aleph_1\text{--complete}}(\mu)>\lambda\} is infinite. The claim concerns consistency results in pcf theory and is stated without a resolution in the paper.

References

Primary source

Saharon Shelah, “On what I do not understand (and have something to say): Part I”, arXiv:math/9906113 (1999).

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