Nowhere dense choices and π-weight



Abstract

The paper is devoted to inequalities between π0(X) and πd(X) where
π0(X) := min{π(U): U open and non-empty subset of X},
πd(X) := min{|𝓑|: every open and dense subset of X containes an element from 𝓑}.
From these definitions πd(X) ≤ π0(X) for every space X. In the paper we construct a space X for which πd(X)=ω1 and π0(X)=20.


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Published : 1986-09-30


JuhászI., & WeissW. A. R. (1986). Nowhere dense choices and π-weight. Annales Mathematicae Silesianae, 2, 85-91. Retrieved from https://journals.us.edu.pl/index.php/AMSIL/article/view/14327

Istvan Juhász 
Institute of Mathematics, Hungarian Academy of Science  Hungary
William A. R. Weiss 
Department of Mathematics, University of Toronto, Canada  Canada



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