A new combinatorial characterization of the minimal cardinality of a subset of R which is not of first category

dc.creatorTyszka, Apoloniusz
dc.date1999-11-17
dc.date1999-11-30
dc.date.accessioned2026-07-07T05:31:38Z
dc.date.available2026-07-07T05:31:38Z
dc.descriptionLet M denote the ideal of first category subsets of R. We prove that min{card X: X \subseteq R, X \not\in M} is the smallest cardinality of a family S \subseteq {0,1}^ωwith the property that for each f: ω-> \bigcup_{n \in ω}{0,1}^n there exists a sequence {a_n}_{n \in ω} belonging to S such that for infinitely many i \in ωthe infinite sequence {a_{i+n}}_{n \in ω} extends the finite sequence f(i). We inform that S \subseteq {0,1}^ωis not of first category if and only if for each f: ω-> \bigcup_{n \in ω}{0,1}^n there exists a sequence {a_n}_{n \in ω} belonging to S such that for infinitely many i \in ωthe infinite sequence {a_{i+n}}_{n \in ω} extends the finite sequence f(i).
dc.description4 pages, LaTeX 209, a new theorem added (see Abstract and Note on p.2)
dc.identifierhttps://arxiv.org/abs/math/9911122
dc.identifierhttp://arxiv.org/abs/math/9911122
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/79420
dc.subjectLogic
dc.subject03E05 (Primary) 54A25 (Primary) 26A03 (Secondary)
dc.titleA new combinatorial characterization of the minimal cardinality of a subset of R which is not of first category
dc.typetext

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