Weakly homogeneous forcing changing the cofinality of the first inaccessible
Weakly homogeneous forcing changing the cofinality of the first inaccessible
A forcing notion is weakly homogeneous if its forcing relation is invariant under automorphisms of the forcing, and a forcing adds bounded subsets when the generic extension contains new subsets of ordinals below the relevant cardinal. The cofinality of a cardinal is the least order type of an unbounded subset of it.
Consistency conjecture. It is consistent, relative to the existence of large cardinals, that there is a weakly homogeneous forcing which changes the cofinality of the first inaccessible to without adding bounded subsets.
This conjecture asks whether the obstruction established for changing the cofinality of the first inaccessible to can be avoided when the target cofinality is . The required large-cardinal strength is not specified here, and the consistency claim remains open in the supplied text.
Sources & referencesView supporting material
Primary source
Yair Hayut and Asaf Karagila, “Restrictions on Forcings That Change Cofinalities”, arXiv:1502.02165 (2015).
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