Destroying Guessing Principles

04.05.2023 15:00 - 15:50

H. Mildenberger (U of Freiburg, DE)

An Ostaszewski club sequence is a weakening of Jensen's diamond. In contrast to the diamond, the club does not imply the continuum hypothesis. Numerous questions about the club stay open, and we know only few models in which there is just a club sequence but no diamond sequence. In recent joint work with Shelah we found that a winning strategy for the completeness player in a bounding game on a forcing order does not suffice to establish the club in the extension.




HS 11, 2. OG, OMP 1