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Hurewicz scheme. (English) Zbl 1177.03049
Summary: We present a simple proof of Hurewicz theorem saying that every coanalytic non-$$G_\delta$$-set $$C$$ in a Polish space contains a countable set $$L\subseteq C$$ without isolated points such that $$(\overline{L}\setminus L)\cap C=\emptyset$$.

##### MSC:
 03E15 Descriptive set theory 42A20 Convergence and absolute convergence of Fourier and trigonometric series
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