On Generalizations of Lavrentieff’s Theorem for Polish Group Actions
نویسنده
چکیده
It is shown that for every Polish group G that is not locally compact there is a continuous action a of G on a Π1-complete subset A of a Polish space X such that a cannot be extended to any superset of A in X. This answers a question posed by Becker and Kechris and shows that an earlier theorem of them is optimal in several aspects.
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تاریخ انتشار 2006