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Weekly research seminar
Organizers
- prof. dr hab. Witold Marciszewski
- prof. dr hab. Piotr Zakrzewski
Information
Wednesdays, 4:15 p.m. , room: 5050Research fields
List of talks
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Nov. 20, 2024, 4:15 p.m.
Tomasz Weiss (Cardinal Stefan Wyszyński University in Warsaw)
Some remarks on subsets of R defined in terms of the translations of sets which belong to the four most common sigma ideals in R
We are interested in subsets of the Cantor space C. Assume that M denotes meager sets, N stands for null sets, M/\N is the intersection ideal, and + is the standard addition in C. We …
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Nov. 13, 2024, 4:15 p.m.
Grzegorz Plebanek (University of Wrocław)
On embeddings of measure algebras into quotients of P(\omega) (On embeddings of measure algebras into quotients of P(\omega))
We discuss results, due to D.H. Fremlin, on the subject indicated in the title. Those are closely related to so-called uniformly distributed sequences and other sequential properties in spaces of measures. Additional information can be …
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Nov. 6, 2024, 4:15 p.m.
Damian Sobota (Universität Wien, Kurt Gödel Research Center for Mathematical Logic)
On isometric embeddings of separable spaces C(L) in arbitrary spaces C(K) (On isometric embeddings of separable spaces C(L) in arbitrary spaces C(K))
Supplementing and expanding classical results, for compact spaces K and L, L metric, and their Banach spaces C(L) and C(K) of continuous real-valued functions, we provide several characterizations of the existence of isometric embeddings of …
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Oct. 30, 2024, 4:15 p.m.
Taras Banakh (Ivan Franko National University of Lviv and UJK Kielce)
Algebra and Geometry in Liners (Algebra and Geometry in Liners)
We shall discuss the interplay between algebra and geometry in (affine or projective) liners, and also present selected open problems in this fascinating field of mathematics. More information can be found in the book "Geometry …
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Oct. 23, 2024, 4:15 p.m.
Piotr Szewczak (Cardinal Stefan Wyszyński University in Warsaw)
Perfectly meager sets in the transitive sense and the Hurewicz property (Perfectly meager sets in the transitive sense and the Hurewicz property)
We work in the Cantor space with the usual group operation +. A set X is perfectly meager in the transitive sense if for any perfect set P there is an F-sigma set F containing …
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Oct. 16, 2024, 4:15 p.m.
ARKADY LEIDERMAN (Ben-Gurion University of the Negev, Beer Sheva)
ON UNIFORMLY CONTINUOUS SURJECTIONS BETWEEN Cp-SPACES OVER METRIZABLE SPACES
See the enclosed pdf file
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Oct. 9, 2024, 4:15 p.m.
Maciej Korpalski (University of Wrocław)
Barely alternating real almost chains and extension operators for compact lines
Consider an almost chain $\mathcal{A} = \{A_x \subset \omega: x \in X\}$ for some separable linearly ordered set $X$, so a family of subsets of $\omega$ such that for all $x < y, x, y\in …
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June 12, 2024, 4:15 p.m.
Tomasz Żuchowski (University of Wrocław)
The Nikodym property and filters on ω
An infinite Boolean algebra A is said to have the Nikodym property when every pointwise bounded sequence of measures on A is uniformly bounded. For a free filter F on ω we consider the space …
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June 5, 2024, 4:15 p.m.
Jan Kostrzon (Doctoral School of Exact and Natural Sciences UW)
Towards stratification of Sealing Theorems
Sealing Theorems are very strong generic absoluteness principles formulated by Hugh Woodin. Whether the strongest one of them follows from the existence of some large cardinal is an open problem, very important in inner model …
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May 22, 2024, 4:15 p.m.
Lyubomyr Zdomskyy (Technische Universit¨at Wien)
Countable spaces, realcompactness, and cardinal characteristics.
In this talk we shall analyze the realcompactness number of countable spaces. In particular, we plan to show that for a cardinal \kappa, there exists a countable Tychonoff space X without isolated points such that …
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May 15, 2024, 4:15 p.m.
Grzegorz Plebanek (University of Wrocław)
Complemented subspaces of C(K x L)
We prove that whenever K and L are non-scattered compacta then the Banach space C(K x L) contains a complemented copy of C[0,1]. This is joint work with Jakub Rondos and Damian Sobota.
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May 8, 2024, 4:15 p.m.
Piotr Borodulin-Nadzieja (University of Wrocław)
P-measures in models without P-points
I will discuss the existence of P-measures (a P-measure is an analog of the notion of P-point in the realms of finitely additive measures on omega) in the models without P-points. In particular I will …
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April 24, 2024, 4:15 p.m.
Krzysztof Zakrzewski (Doctoral School of Exact and Natural Sciences UW)
Function spaces on Corson-like compacta
Recall that a compact space is Eberlein compact if it is homeomorphic to a subspace of some Banach space equipped with the weak topology. A compact space is \omega-Corson compact if it embeds into a …
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April 17, 2024, 4:15 p.m.
Jakub Andruszkiewicz (Doctoral School of Exact and Natural Sciences UW)
Existence of many finitely generated precompact subgroups of G and L_0(G)
For a Polish group G one can define L_0(G) as the set of all (Borel or) Lebesgue measurable functions from [0,1] to G. This set, after identifying functions that are equal up to a set …
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April 10, 2024, 4:15 p.m.
Kacper Kucharski (Doctoral School of Exact and Natural Sciences UW)
On property (B) in function spaces
A topological space Z has the property (B) of Banakh if there exists a countable family of closed nowhere dense subsets of Z that absorbs all compact subsets of Z, i.e., each compact subset of …
