Akademik Veri Yönetim Sistemi
49th Annual International Liver Congress of the European-Association-for-the-Study-of-the-Liver, London, Kanada, 9 - 13 Nisan 2014, cilt.60
A space $X$ has a $\mathbb{Q}$-diagonal if $X^2\setminus \Delta$ has a $\mathcal{K}(\mathbb{Q})$-directed compact cover. We show that any compact space with a $\mathbb{Q}$-diagonal is metrizable, hence any Tychonorff space with a $\mathbb{Q}$-diagonal is cosmic. These give a positive answer to Problem 4.2 and Problem 4.8 in \cite{COT11} raised by Cascales, Orihuela and Tkachuk.