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

Abstract

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