2 00 5 Can a Borel group be generated by a Hurewicz subspace ?
نویسنده
چکیده
In this paper we formulate three problems concerning topological properties of sets generating Borel non-σ-compact groups. In case of the concrete Fσδ-subgroup of {0, 1}ω×ω this gives an equivalent reformulation of the Scheepers diagram problem.
منابع مشابه
Hurewicz-like Tests for Borel Subsets of the Plane
Let ξ ≥ 1 be a countable ordinal. We study the Borel subsets of the plane that can be made Πξ by refining the Polish topology on the real line. These sets are called potentially Πξ . We give a Hurewicz-like test to recognize potentially Πξ sets. 1. Preliminaries in dimension one Let us recall some results in dimension one before studying Borel subsets of the plane. In descriptive set theory, a ...
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We study subgroups of Z which possess group theoretic properties analogous to properties introduced by Menger (1924), Hurewicz (1925), Rothberger (1938), and Scheepers (1996). We obtain purely combinatorial characterizations of these properties, and combine them with other techniques to solve several questions of Babinkostova, Kočinac, and Scheepers. We also show that, while the Menger Conjectu...
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