The tower number and the ultrafilter number on an inaccessible cardinal kappa with compactness at kappa++

12.10.2023 16:45 - 17:30

R. Honzík (Charles U, Prague, CZ)

We will use a construction due to Brooke-Taylor, Fischer, Friedman, and Montoya and construct a model where \(\kappa\) is inaccessible and we have (among other things) \(\kappa^+ = \mathfrak{t}(\kappa) < \mathfrak{u}(\kappa) < 2^\kappa\), and the tree property, and the negation of the weak Kurepa Hypothesis hold at \(\kappa^{++}\). This is an application of a general method based on indestructibility of various compactness principles by further forcings. The consistency of \(\kappa^+ < \mathfrak{t}(\kappa) \le \mathfrak{u}(\kappa) < 2^\kappa\) with the same compactness principles remains open because it is not solved by the present technique.

Organiser:

KGRC

Location:

SR 10, 1. Stock, Koling. 14-16, 1090 Wien