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.
机构:
Alfred Renyi Inst Math, POB 127, H-1364 Budapest, Hungary
Eotvos Lorand Univ, Inst Math, Pazmany Peter S 1-c, H-1117 Budapest, HungaryAlfred Renyi Inst Math, POB 127, H-1364 Budapest, Hungary
Elekes, Marton
Poor, Mark
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h-index: 0
机构:
Eotvos Lorand Univ, Inst Math, Pazmany Peter S 1-c, H-1117 Budapest, HungaryAlfred Renyi Inst Math, POB 127, H-1364 Budapest, Hungary