On the Spectrum of Characters of Ultrafilters

Shimon Garti, Menachem Magidor, Saharon Shelah
2018 Notre Dame Journal of Formal Logic  
We show that the character spectrum Sp_χ(λ), for a singular cardinal λ of countable cofinality, may include any prescribed set of regular cardinals between λ and 2^λ.
doi:10.1215/00294527-2018-0006 fatcat:tygit6wlznhabevusruzr6zkoa