The structure of pleasant ideals

Christopher Leary

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arXiv · math/9308203

The structure of pleasant ideals

Christopher Leary

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Abstract

Normal ideals on regular uncountable cardinals are familiar objects. We investigate ideals that are pleasant--while a normal ideal is closed under arbitrary diagonal unions, a pleasant ideal is closed only under diagonal unions indexed by sets that are elements of the ideal. We show any selective ideal extending the nonstationary ideal must be normal.

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Christopher Leary. 1993-08-24. The structure of pleasant ideals. https://arxiv.org/abs/math/9308203

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