Haar null sets and the consistent reflection of non-meagreness

Márton Elekes, Juris Steprāns

A subset $X$ of a Polish group $G$ is called \emph{Haar null} if there exists a Borel set $B\supset X$ and Borel probability measure $\mu$ on $G$ such that $\mu (gBh)=0$ for every $g,h…