Combining ideas from two of our previous papers, we refine Arhangel'skii Theorem by proving a cardinal inequality of which this is a special case: any increasing union of strongly discretely Lindelof spaces with countable free sequences and countable pseudocharacter has cardinality at most continuum. We then give a partial positive answer to a problem of Alan Dow on reflection of cardinality by closures of discrete sets.

SPADARO, S.D. (2013). Increasing chains and discrete reflection of cardinality. RENDICONTI DELL'ISTITUTO DI MATEMATICA DELL'UNIVERSITÀ DI TRIESTE, 45, 73-82.

Increasing chains and discrete reflection of cardinality

SPADARO, SANTI DOMENICO
2013

Abstract

Combining ideas from two of our previous papers, we refine Arhangel'skii Theorem by proving a cardinal inequality of which this is a special case: any increasing union of strongly discretely Lindelof spaces with countable free sequences and countable pseudocharacter has cardinality at most continuum. We then give a partial positive answer to a problem of Alan Dow on reflection of cardinality by closures of discrete sets.
Settore MAT/03 - Geometria
SPADARO, S.D. (2013). Increasing chains and discrete reflection of cardinality. RENDICONTI DELL'ISTITUTO DI MATEMATICA DELL'UNIVERSITÀ DI TRIESTE, 45, 73-82.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10447/480948
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