Organizatorzy

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

Informacje

środy, 16:15 , sala: 5050

Dziedziny badań

Topologia i teoria mnogości

Lista referatów

16 marca 2016 16:15
Adam Kwela (Uniwersytet Gdański)
Ideałowe klasy Baire'a
Praca wspólna z Marcinem Staniszewskim. Zbadamy klasy Baire'a względem ideałowej e-zbieżności ("equal convergence" lub "quasi-normal convergence") generowane przez rodziny funkcji ciągłych i quasi-ciągłych. Przy okazji przypomnimy dotychczasowe wyniki z tej tematyki.
3 lutego 2016 16:15
Damian Sobota (doktorant IMPAN)
On families deciding Rosenthal's lemma
A classical version of Rosenthal's lemma reads as follows. Given a sequence (mu_k) of finitely additive bounded positive measures on P(N) and an infinite antichain (a_n) in P(N), for every epsilon > 0 there exists …
27 stycznia 2016 16:15
Grzegorz Plebanek (Uniwersytet Wrocławski)
Uzwarcenia liczb naturalnych i przestrzeń Banacha c_0
Wraz z P. Drygierem badaliśmy, dla jakich uzwarceń \gammaN przestrzeni dyskretnej N naturalna kopia c_0 jest dopełnialna w C(\gammaN). W szczególności skonstruowaliśmy uzwarcenie z narostem ośrodkowym, które nie ma tej własności. Konstrukcja nie wymaga dodatkowych …
13 stycznia 2016 16:15
Phillip Wesolek ( Université catholique de Louvain )
Chief factors in Polish groups
Abstract: (Joint work with Colin Reid.) For a Polish group G, closed normal subgroups L
16 grudnia 2015 16:15
Piotr Zakrzewski (University of Warsaw)
Paradoxical decompositions into pieces with the Baire Property - continuation.
9 grudnia 2015 16:15
Piotr Zakrzewski (University of Warsaw)
Paradoxical decompositions into pieces with the Baire Property
I will present the following theorem due to Andrew Marks and Spencer Unger: Suppose G is a group of Borel automorphisms of a Polish space X. Then if X has a G-paradoxical decomposition into arbitrary …
2 grudnia 2015 16:15
Tomasz Weiss (Cardinal Stefan Wyszyński University in Warsaw)
On products of gamma sets - continuation from 4.11.2015
The presentation is based on the paper "Selective covering properties of product spaces, part 2,gamma spaces", preprint 2013, by A.Miller,B.Tsaban,L.Zdomsky.
25 listopada 2015 16:15
Rafał Filipów (The University of Gdańsk)
A critical ideal with respect to Mazurkiewicz's theorem in terms of the Katetov order
Consider a property of ideals: property(I). One can ask whether there is a critical ideal C for property(I) in terms of the Katetov order <_K i.e. property(I) <=> C <_K I. Many examples of critical …
18 listopada 2015 16:15
Taras Banakh (Lviv National University and UJK Kielce)
The closed Steinhaus properties of $σ$-ideals on topological groups
Abstract: We prove that any meager quasi-analytic subgroup of a topological group $G$ belongs to every $\sigma$-ideal $\mathcal I$ on $G$ possessing the closed ±n-Steinhaus property for some $n∈\mathbb N$. An ideal I on a …
4 listopada 2015 16:15
Tomasz Weiss (Cardinal Stefan Wyszyński University in Warsaw)
On products of gamma sets
I will present the following theorem due to Miller, Tsaban and Zdomsky:It is consistent with ZFC that there are two gamma sets whose cartesian product is not a Menger set. This result answers in the …
21 października 2015 16:15
Michał Korch (doktorant UW)
Generalised Egorov’s Statement for ideals
Tomasz Weiss has proven that the statement obtained from the classic Egorov's Theorem by dropping the measurability assumption (so called generalised Egorov's statement) is independent from ZFC (we restrict our attention to real functions). We …
14 października 2015 16:15
Piotr Szewczak; Coauthor: Boaz Tsaban (Bar-Ilan University, Israel) (Cardinal Stefan Wyszyński University in Warsaw)
Products of Menger spaces
A topological space X is Menger if for every sequence of open covers O_1, O_2, . . . there are ﬁnite subfamilies F_1 of O_1, F_2 of O_2, . . . such that their union …
7 października 2015 16:15
Maciej Malicki (Warsaw School of Economics)
Polish groups with ample generics and analytic P-ideals
A Polish group has ample generics if all its diagonal conjugation actions have a comeager orbit. This property has a number of interesting implications, e.g. automatic continuity of homomorphisms into separable groups. Until recently, all …
17 czerwca 2015 16:15
Brice Mbombo (Sao Paulo)
Ramsey properties for finite dimensional normed spaces
10 czerwca 2015 16:15
Piotr Koszmider (IMPAN)
Uncountable equilateral sets in Banach spaces
A set A in a Banach space X is said to be equilateral if there is a real r such that the distance between any two distinct elements of A is r. We construct the …