加载中…
We solve two long-standing open problems regarding the combinatorics of . We answer a question of Shelah by showing that it is consistent for any that holds and there is a stationary set of points of cofinality which is not in the approachability ideal. As a corollary, we obtain a model where the notions of goodness and approachability are distinct for stationarily many points of cofinality , answering an open question of Cummings, Foreman, and Magidor.

生成讲解博客的中文版本

生成AI智能校验的中文版本