## Files in this item

FilesDescriptionFormat

application/pdf

 Title: Generic behaviour of a measure preserving transformation Author(s): Etedadialiabadi, Mahmood Director of Research: Solecki, Slawomir Doctoral Committee Chair(s): van den Dries, Lou Doctoral Committee Member(s): Hieronymi, Philipp; Tserunyan, Anush Department / Program: Mathematics Discipline: Mathematics Degree Granting Institution: University of Illinois at Urbana-Champaign Degree: Ph.D. Genre: Dissertation Subject(s): Measure preserving transformation Measurable functions Abstract: We study two different problems: generic behavior of a measure preserving transformation and extending partial isometries of a compact metric space. In Chapter $1$, we consider a result of Del Junco--Lema\'nczyk [\ref{DL_B}] which states that a generic measure preserving transformation satisfies a certain orthogonality conditions, and a result of Solecki [\ref{S1_B}] which states that every continuous unitary representations of $L^0(X,\mathbb{T})$ is a direct sum of action by multiplication on measure spaces $(X^{|\kappa|},\lambda_\kappa)$ where $\kappa$ is an increasing finite sequence of non-zero integers. The orthogonality conditions introduced by Del Junco--Lema\'nczyk motivates a condition, which we denote by the DL-condition, on continuous unitary representations of $L^0(X,\mathbb{T})$. We show that the probabilistic (in terms of category) statement of the DL-condition translates to some deterministic orthogonality conditions on the measures $\lambda_\kappa$. Also, we show a certain notion of disjointness for generic functions in $L^0(\mathbb{T})$ and a similar orthogonality conditions to the result of Del Junco--Lema\'nczyk for a generic unitary operator on a Hilbert space $H$. In Chapter $2$, we show that for every $\epsilon>0$, every compact metric space $X$ can be extended to another compact metric space, $Y$, such that every partial isometry of $X$ extends to an isometry of $Y$ with $\epsilon-$distortion. Furthermore, we show that the problem of extending partial isometries of a compact metric space, $X$, to isometries of another compact metric space, $X\subseteq Y$, is equivalent to extending partial isometries of $X$ to certain functions in $\operatorname{Homeo}(Y)$ that look like isometries from the point of view of $X$. Issue Date: 2017-12-08 Type: Text URI: http://hdl.handle.net/2142/99247 Rights Information: Copyright 2017 Mahmood Etedadialiabadi Date Available in IDEALS: 2018-03-132020-03-14 Date Deposited: 2017-12