کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4660693 1344380 2009 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Covering by discrete and closed discrete sets
موضوعات مرتبط
مهندسی و علوم پایه ریاضیات هندسه و توپولوژی
پیش نمایش صفحه اول مقاله
Covering by discrete and closed discrete sets
چکیده انگلیسی

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.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Topology and its Applications - Volume 156, Issue 4, 1 February 2009, Pages 721-727