On the strong Freese-Nation property
arXiv:1412.7443 · doi:10.1007/s11083-016-9389-9
Abstract
We show that there is a boolean algebra that has the Freese-Nation property (FN) but not the strong Freese-Nation property (SFN), thus answering a question of Heindorf and Shapiro. Along the way, we produce some new characterizations of the FN and SFN in terms of sequences of elementary submodels.
19 pages; minor correction in Section 5