By a theorem of Hajnal and Juhasz, \(card(X)\leq exp(exp(spread(X)))\) holds for all Hausdorff spaces \(X\). Juhasz asked, if the second \(exp\) is necessary. I will present a result which shows that \(card(X)=exp(exp(spread(X)))\) for a \(T_3\) space \(X\) with spread \(\omega_1\) is consistent. Previously, Fedorcuk constructed from \(\diamondsuit\) a \(T_3\) space \(X\) with spread \(\omega\) and \(card(X)=exp(exp(spread(X)))\).
A remark on a theorem by Hajnal and Juhasz
13.03.2008 15:00 - 16:30
Organiser:
KGRC
Location:
SR 101, 2. St., Währinger Str. 25