Adding cofinal countable sequences through multiple regular cardinals by ssp forcing
Abstract
We present a direct construction of stationary set preserving forcings that make ω-cofinal all the members of some arbitrary set K of regular cardinals > ω1. In addition, it is made possible to ensure that no other uncountable regular cardinals from the ground model acquire countable cofinality in the forcing extension. Our method is elementary, being based on a combinatorial argument by Foreman and Magidor together with generalizations of typical side-condition arguments and needs no assumptions beyond ZFC.
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