Borel hierarchies in infinite products of Polish spaces
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چکیده
Let H be a product of countably infinite number of copies of an uncountable Polish space X . Let Σξ (Σξ ) be the class of Borel sets of additive class ξ for the product of copies of the discrete topology on X (the Polish topology on X), and let B = ∪ξ<ω1Σξ . We prove in the Lévy–Solovay model that Σξ = Σξ ∩B
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تاریخ انتشار 2005