Recent and upcoming talks by Aleksander Cieślak

Aleksander Cieślak: Ideals of subsets of plane

Sunday, September 10, 2017, 17:15 Wrocław University of Technology, 215 D-1 Speaker: Aleksander Cieślak (Wrocław University of Technology) Title: Ideals of subsets of plane Abstract: For given two ideals $I$ and $J$ of subsets of Polish space $X$ we define a Fubini product $I\times J$ as all these subsets of plane $X^2$ which can be covered by a Borel set $B$ such that $I$-almost all its vertical sections are $J$-small. continue reading…

Aleksander Cieślak: Cohen-stable families of subsets of integers

Tuesday, June 13, 2017, 17:15 Wrocław University of Technology, 215 D-1 Speaker: Aleksander Cieślak (Wroclaw University of Science and Technology) Title: Cohen-stable families of subsets of integers Abstract: A mad family is Cohen-stable if it remains maximal in any Cohen generic extension. continue reading…

Aleksander Cieślak: Indestructible tower

Tuesday, April 11, 2017, 17:15 Wrocław University of Technology, 215 D-1 Speaker: Aleksander Cieślak (Wroclaw University of Science and Technology) Title: Indestructible tower Abstract: Following the Kunen’s construction of m.a.d. family which is indestructible over adding $\omega_2$ Cohen reals we provide analogous construction for indestructibe tower. continue reading…

Aleksander Cieślak: Strongly meager sets and subsets of the plane

Tuesday, December 20, 2016, 17:15 Wrocław University of Technology, 215 D-1 Speaker: Aleksander Cieślak (Wrocław University of Science and Technology) Title: Strongly meager sets and subsets of the plane Abstract: We will show some results proved by J. continue reading…

Aleksander Cieślak: Nonmeasurable images in Polish space with respect to selected sigma ideals

Tuesday, October 11, 2016, 17:15 Wrocław University of Technology, 215 D-1 Speaker: Aleksander Cieślak (Wrocław University of Science and Technology) Title: Nonmeasurable images in Polish space with respect to selected sigma ideals Abstract: We present results on nonmeasurability (with respect to a selected sigma-ideal on a Polish space) of images of functions defined on Poilish spaces. continue reading…

Aleksander Cieślak: Filters and sets of Vitali’s type

Thursday, January 1, 1970, 17:15 Wrocław University of Technology, 215 D-1 Speaker: Aleksander Cieślak (Wrocław University of Technology) Title: Filters and sets of Vitali’s type Abstract: In construction of classical Vitali set on $\{0,1\}^{\omega}$ we use filter of cofinite sets to define rational numbers. continue reading…

Aleksander Cieślak: On nonmeasurable subsets of $\mathbb{R}$ and $\mathbb{R}^2$

Tuesday, October 27, 2015, 17:15 Wrocław University of Technology, 215 D-1 Speaker: Aleksander Cieślak (Wrocław University of Technology) Title: On nonmeasurable subsets of $\mathbb{R}$ and $\mathbb{R}^2$ Abstract: I would like to present some results connected with the existence of a subset $X$ of the square $[0,1]^2$ with the property that for any line $L$ outside $[0,1]^2$ the projection $\pi_L[X]$ is completely nonmeasurable in some interval with respect to selected $sigma$-ideal with Borel base on the line $L$. continue reading…