Organizers

prof. dr hab. Witold Marciszewski
prof. dr hab. Piotr Zakrzewski

Information

Wednesdays, 4:15 p.m. , room: 5050

Research fields

Topology and Set Theory

List of talks

March 22, 2017, 4:15 p.m.
Grzegorz Plebanek (University of Wrocław )
Boolean algebras and small independent families
We consider Boolean algebras generated by families that can be decomposed into countably many pieces so that no part contains an infinite independent sequence. The property is denoted by WRN because it is closely related …
March 15, 2017, 4:15 p.m.
Tomasz Cieśla (University of Warsaw)
Borel circle squaring
In 1925 Alfred Tarski asked whether a square is equidecomposable by isometries with a disc of the same area. This question was answered in the affirmative in 1990 by Laczkovich. In 2015 Grabowski, Mathe and …
March 8, 2017, 4:15 p.m.
Jacek Tryba (University of Gdańsk)
Homogeneity of ideals
The homogeneity family of the ideal I is a family of subsets such that the restriction of I to this subset is isomorphic to I. We say that an ideal I is homogeneous if all …
March 1, 2017, 4:15 p.m.
Witold Marciszewski (Uniwersytet Warszawski)
Extension operators and twisted sums - part 2.
Jan. 25, 2017, 4:15 p.m.
Witold Marciszewski (Uniwersytet Warszawski)
Extension operators and twisted sums
Jan. 11, 2017, 4:15 p.m.
Wiesław Kubiś (Cardinal Stefan Wyszyński University in Warsaw)
Weak amalgamation classes and their limits
We will present the construction and basic properties of limits of classes of finitely generated models satsifying some natural conditions, in particular, the weak amalgamation. This is a straightforward extension of the classical Fraisse theory …
Dec. 14, 2016, 4:15 p.m.
Taras Banakh (Lviv National University and UJK Kielce)
generically) Haar-meager and Haar-null sets in Polish groups. (On)
We shall discuss recent joint results with Eliza Jablonska related to (generically) Haar-meager and Haar-null sets in Polish groups.
Dec. 7, 2016, 4:15 p.m.
Maciej Malicki (Warsaw School of Economics)
Groups of measurable functions - part 2.
Nov. 30, 2016, 4:15 p.m.
Maciej Malicki (Warsaw School of Economics)
Groups of measurable functions
Let G be a Polish group, and let m be a non-atomic probability measure on the interval [0,1]. We define L_0(G) to be the Polish group of all m-equivalence classes of m -measurable functions with …
Nov. 23, 2016, 4:15 p.m.
Tomasz Weiss (Cardinal Stefan Wyszyński University in Warsaw)
More remarks on the intersection ideal M /\ N - part 2.
Nov. 16, 2016, 4:15 p.m.
Tomasz Weiss (Cardinal Stefan Wyszyński University in Warsaw)
More remarks on the intersection ideal M /\ N
We prove in ZFC that every (M /\ N)-additive set is N-additive.
Nov. 9, 2016, 4:15 p.m.
Martin Dolezal (Uniwersytet Warszawski)
Haar meager sets - part 2.
Oct. 26, 2016, 4:15 p.m.
Martin Dolezal (Uniwersytet Warszawski)
Haar meager sets
The notion of Haar meager sets in abelian Polish groups was introduced by Darji. Haar meager sets form a topological counterpart to Haar null sets defined by Christensen. We show some analogies of Haar meager …
Oct. 19, 2016, 4:15 p.m.
Tomasz Cieśla (doktorant UW)
An example of Eberlein compact that is not bisequential
Peter Nyikos gave an example of Eberlein compact that is not bisequential during his talk on Eighth Summer Conference on General Topology and its Applications (over 20 years ago). According to my knowledge he never …
Oct. 12, 2016, 4:15 p.m.
Adam Krawczyk (Uniwersytet Warszawski)
Gry Banacha - Mazura na strukturach relacyjnych