A space is monotonically Lindelof (mL) if one can assign to every open cover U a countable open refinement r (U) (still covering the space) so that r (U) refines r (V) whenever U refines V. Some examples of mL and non-mL spaces are considered. In particular, it is shown that the product of a mL space and the convergent sequence need not be mL, that some L-spaces are mL, and that C-p (X) is mL only for countable X. (c) 2007 Elsevier B.V. All rights reserved.
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Univ Catania, Dept Math & Comp Sci, Citta Univ Viale A Doria 6, I-95125 Catania, ItalyUniv Catania, Dept Math & Comp Sci, Citta Univ Viale A Doria 6, I-95125 Catania, Italy
Bella, Angelo
Spadaro, Santi
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Univ Catania, Dept Math & Comp Sci, Citta Univ Viale A Doria 6, I-95125 Catania, ItalyUniv Catania, Dept Math & Comp Sci, Citta Univ Viale A Doria 6, I-95125 Catania, Italy
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Univ Autonoma Metropolitana, Dept Matemat, Av San Rafael Atlixco 186, Mexico City 09340, DF, MexicoUniv Autonoma Metropolitana, Dept Matemat, Av San Rafael Atlixco 186, Mexico City 09340, DF, Mexico