677 research outputs found

    Perfect subsets of generalized Baire spaces and long games

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    We extend Solovay's theorem about definable subsets of the Baire space to the generalized Baire space λλ{}^\lambda\lambda, where λ\lambda is an uncountable cardinal with λ<λ=λ\lambda^{<\lambda}=\lambda. In the first main theorem, we show that that the perfect set property for all subsets of λλ{}^{\lambda}\lambda that are definable from elements of λOrd{}^\lambda\mathrm{Ord} is consistent relative to the existence of an inaccessible cardinal above λ\lambda. In the second main theorem, we introduce a Banach-Mazur type game of length λ\lambda and show that the determinacy of this game, for all subsets of λλ{}^\lambda\lambda that are definable from elements of λOrd{}^\lambda\mathrm{Ord} as winning conditions, is consistent relative to the existence of an inaccessible cardinal above λ\lambda. We further obtain some related results about definable functions on λλ{}^\lambda\lambda and consequences of resurrection axioms for definable subsets of λλ{}^\lambda\lambda

    Baire spaces and infinite games

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    It is well known that if the nonempty player of the Banach-Mazur game has a winning strategy on a space, then that space is Baire in all powers even in the box topology. The converse of this implication may be true also: We know of no consistency result to the contrary. In this paper we establish the consistency of the converse relative to the consistency of the existence of a proper class of measurable cardinals.Comment: 21 page
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