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

May 27, 2015, 4:15 p.m.
Damian Sobota (doktorant IMPAN)
Small Boolean algebras with the Nikodym property
Let A be a Boolean algebra. A sequence of measures (mu_n) on A is: * pointwise bounded if the sequence (|mu_n(a)|) is bounded for every a in A; * uniformly bounded if the sequence (||mu_n||) …
May 20, 2015, 4:15 p.m.
Grzegorz Plebanek (Uniwersytet Wrocławski)
Converging sequences of measures and complemented copies of c_0
If K is an infinite compact space then the Banach space C(K) contains natural copies of c_0. The question whether a given copy of c_0 is complemented in C(K) can be expressed in terms of …
May 13, 2015, 4:15 p.m.
Marcin Sabok (IMPAN)
Classification problems in symbolic dynamics
During this talk I will discuss the descriptive set-theoreticcomplexity of the topological conjugacy relation for free minimalG-subshifts for various countable groups G. For residually finite countablegroups G we will see that there exists a probability …
May 6, 2015, 4:15 p.m.
Marta Frankowska (Uniwersytet Gdański)
The density topology in the Cantor space
We consider some properties of ideal (a) defined on 2^{\omega} by classical density topology. We also discuss the possibility of using the Cantor function to prove analogous results on R.
April 22, 2015, 4:15 p.m.
Mikolaj Krupski (Uniwersytet Warszawski)
On the weak and pointwise topologies in function spaces
For a compact space K we denote by C_w(K) (C_p(K)) the space of continuous real-valued functions on K endowed with the weak (pointwise) topology. During the talk I would like to discuss the following basic …
April 15, 2015, 4:15 p.m.
Adam Kwela (Uniwersytet Gdański)
Zbiory mikroskopijne i ich addytywność
March 25, 2015, 4:15 p.m.
Piotr Borodulin-Nadzieja (Uniwersytet Wrocławski)
Measures on suslinean spaces
We investigate certain measure theoretic versions of Suslin hypothesis.
March 18, 2015, 4:15 p.m.
Grigor Sargsyan (Department of Mathematics, Rutgers University)
Large cardinals, determinacy and inner models
We will investigate the relationship between Large Cardinals, determinacy and inner models, and give a gentle introduction to Godel's program. We will justify the use of large cardinals in set theory and mathematics and give …
March 11, 2015, 4:15 p.m.
Wiesław Kubiś (Jan Kochanowski University in Kielce and Mathematical Institute of the Czech Academy of Sciences)
On perfect monochromatic sets in analytic spaces
It is known that if C is a G-delta symmetric relation in an analytic space and there exists an uncountable C-monochromatic set then there exists also a perfect one. We extend this result to the …
March 4, 2015, 4:15 p.m.
Witold Marciszewski (Uniwersytet Warszawski)
Combinatorial methods in investigations of extension operators
Jan. 21, 2015, 4:15 p.m.
Jacek Tryba (doktorant UG)
BW property for van der Waerden and Hindman ideals
We consider four classes of topological spaces defined with the aid of convergence with respect to ideals on the set of natural numbers and examine the relationships between each other. We also show that two …
Jan. 14, 2015, 4:15 p.m.
Piotr Zakrzewski (Uniwersytet Warszawski)
Combinatorics of ideals -- selectivity versus density; the second part.
An ideal I on $\omega$ is called: - dense if every infinite subset of $\omega$ contains an infinite subset in I, - selective if for every partition (A_n) of $\omega$ such that no finite union …
Dec. 10, 2014, 4:15 p.m.
Piotr Zakrzewski (Uniwersytet Warszawski)
Combinatorics of ideals -- selectivity versus density
An ideal I on $\omega$ is called: - dense if every infinite subset of $\omega$ contains an infinite subset in I, - selective if for every partition (A_n) of $\omega$ such that no finite union …
Dec. 3, 2014, 4:15 p.m.
Piotr Koszmider (IMPAN)
Automorphisms of the Banach space C(N*)
The classical topic of automorphisms of the Boolean algebra P(N)/Fin is one of the most exciting chapters of the set-theoretic research. One of its achievements is the result saying that assuming PFA or OCA+MA any …
Nov. 26, 2014, 4:15 p.m.
Grzegorz Plebanek (Uniwersytet Wrocławski)
On some compactifications of N
We consider (zerodimensional) compactifications of the set of natural numbers such that the remainder is not separable but supports a probability measure. It seems to be unclear if such a compactification can be constructed within …