Non-saturation of the nonstationary ideal on P κ (λ) in case κ ≤ cf (λ) < λ

Pierre Matet (1)

1 LMNO - Laboratoire de Mathématiques Nicolas Oresme

Given a regular cardinal κ > ω 1 and a cardinal λ with κ ≤ cf (λ) < λ, we show that NS κ,λ | T is not λ+-saturated, where T is the set of all a∈Pκ(λ) such that |a|=|a∩κ| and cf(sup(a∩κ))=cf(sup(a))=ω.

Keywords: Pκ(λ); Saturation

Domains: Mathematics [math]; Logic [math.LO]

Pierre Matet. Non-saturation of the nonstationary ideal on P κ (λ) in case κ ≤ cf (λ) < λ. Archive for Mathematical Logic, 2012, 51 (3-4), pp.425-432. ⟨10.1007/s00153-012-0270-2⟩. ⟨hal-02145592⟩