Naively Haar null sets in Polish groups

被引:3
|
作者
Elekes, Marton [1 ,2 ]
Vidnyanszky, Zoltan [1 ]
机构
[1] Hungarian Acad Sci, Atfred Renyi Inst Math, POB 127, H-1364 Budapest, Hungary
[2] Eotvos Lorand Univ, Dept Anal, Pazmany Ps 1-c, H-1117 Budapest, Hungary
关键词
Polish groups; Haar null; Christensen; Shy; Universally measurable; Problem FC; SUBGROUPS;
D O I
10.1016/j.jmaa.2016.08.033
中图分类号
O29 [应用数学];
学科分类号
070104 ;
摘要
Let (G,.) be a Polish group. We say that a set X subset of G is Haar null if there exists a universally measurable set U superset of X and a Borel probability measure mu such that for every g,h epsilon G we have mu,(gUh) = 0. We call a set X naively Haar null if there exists a Borel probability measure A such that for every g, h epsilon G we have mu(gXh) = 0. Generalizing a result of Elekes and Steprans, which answers the first part of Problem FC from Fremlin's list, we prove that in every abelian Polish group there exists a naively Haar null set that is not Haar null. (C) 2016 Published by Elsevier Inc.
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页码:193 / 200
页数:8
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