Nonmeasurable sets and unions with respect to tree ideals

Speaker(s)

Szymon Żeberski

Affiliation

Wrocław University of Technology

Date

Jan. 17, 2018, 4:15 p.m.

Room

room 5050

Seminar

Topology and Set Theory Seminar

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We consider a notion of nonmeasurablity with respect to Marczewski and Marczewski-like tree ideals $s_0$, $m_0$, $l_0$, and $cl_0$. We show that there exists a subset $A$ of the Baire space $\omega^\omega$ which is $s$-, $l$-, and $m$-nonmeasurable, that forms dominating m.a.d. family. We introduce and investigate the notion of $\mbb{T}$-Bernstein sets - sets that intersect but does not containt any body of a tree from a given family of trees $\mbb{T}$. We also acquire some results on $\mc{I}$-Luzin sets, namely we prove that there are no $m_0$-, $l_0$-, and $cl_0$-Luzin sets and that if $\mf{c}$ is a regular cardinal, then the algebraic sum (considered on the real line $\mbb{R}$) of a generalized Luzin set and a generalized Sierpiński set belongs to $s_0, m_0$, $l_0$ and $cl_0$. These results were obtained jointly with M. Michalski and R. Rałowski.

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