Title of article :
Covering by discrete and closed discrete sets
Author/Authors :
Spadaro، نويسنده , , Santi، نويسنده ,
Issue Information :
دوماهنامه با شماره پیاپی سال 2009
Abstract :
Say that a cardinal number κ is small relative to the space X if κ < Δ ( X ) , where Δ ( X ) is the least cardinality of a non-empty open set in X. We prove that no Baire metric space can be covered by a small number of discrete sets, and give some generalizations. We show a ZFC example of a regular Baire σ-space and a consistent example of a normal Baire Moore space which can be covered by a small number of discrete sets. We finish with some remarks on linearly ordered spaces.
Keywords :
Discrete set , Dispersion character , Moore space , ?-space , LOTS , Baire
Journal title :
Topology and its Applications
Journal title :
Topology and its Applications