Dowker-type example and Arhangelskii%26apos;s alpha(2)-property

作者：Bonanzinga Maddalena^*; Matveev Mikhail

来源：Topology and Its Applications, 2013, 160(18): 2351-2355.

DOI：10.1016/j.topol.2013.07.029

• Diagonalization of point-cofinite covers
• alpha(2)-Property

Answering a question of M. Sakai and partially answering a question of NI. Scheepers, we use the Continuum Hypothesis (CH) to show that, for a slight modification of a space constructed by Dowker in 1955, clopen point-cofinite covers can be diagonalized but there is a sequence of open point-cofinite covers that cannot be diagonalized. %26lt;br%26gt;Also this space distinguishes between Arhangelskii%26apos;s alpha(2)-property for C-p(X) and alpha(2)-Property for C-p(X, 2). 2013 Elsevier B.V.

• 出版日期2013-12-1