Aspects of singular cofinality

Assaf Rinot

Abstract


We study properties of closure operators of singular cofinality, and introduce several ZFC sufficient and equivalent conditions for the existence of antichain sequences in posets of singular cofinality.

We also notice that the Proper Forcing Axiom implies the Milner-Sauer conjecture.

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PID: http://hdl.handle.net/10515/sy56d5pr7

Contributions to Discrete Mathematics. ISSN: 1715-0868