Galvin, Fred; Simon, Petr A Čech function in ZFC. (English) Zbl 1118.54002 Fundam. Math. 193, No. 2, 181-188 (2007). Combining earlier results, the authors construct in ZFC a Čech function on \(\omega\), i.e. a nontrivial surjective closure operator \(\varphi:{\mathcal P}(\omega)\to{\mathcal P}(\omega)\). Reviewer: Bernhard Behrens (Göteborg) Cited in 7 Documents MSC: 54A05 Topological spaces and generalizations (closure spaces, etc.) 54G20 Counterexamples in general topology 03E05 Other combinatorial set theory Keywords:closure space; almost disjoint family; fixed-point; \(\kappa\)-additive PDFBibTeX XMLCite \textit{F. Galvin} and \textit{P. Simon}, Fundam. Math. 193, No. 2, 181--188 (2007; Zbl 1118.54002) Full Text: DOI