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Cotygodniowe seminarium badawcze
Organizatorzy
- prof. dr hab. Witold Marciszewski
- prof. dr hab. Piotr Zakrzewski
Informacje
środy, 16:15 , sala: 5050Dziedziny badań
Lista referatów
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8 maja 2024 16:15
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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24 kwietnia 2024 16:15
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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17 kwietnia 2024 16:15
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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10 kwietnia 2024 16:15
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 …
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20 marca 2024 16:15
Piotr Zakrzewski (UW)
On two consequences of CH established by Sierpiński, part 2
We study the relations between two consequences of the Continuum Hypothesis discovered by Wacław Sierpiński, concerning uniform continuity of continuous functions and uniform convergence of sequences of real-valued functions, defined on uncountable subsets of the …
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13 marca 2024 16:15
Piotr Zakrzewski (UW)
On two consequences of CH established by Sierpiński
We study the relations between two consequences of the Continuum Hypothesis discovered by Wacław Sierpiński, concerning uniform continuity of continuous functions and uniform convergence of sequences of real-valued functions, defined on uncountable subsets of the …
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6 marca 2024 16:15
Kamil Ryduchowski
Lusin sets and uncountable Auerbach systems
Hajek, Kania and Russo showed that under CH there is an equivalent renorming of the Banach space c_0(omega_1) without uncountable Auerbach systems. It is not known whether extra set-theoretic assumptions can be dropped here. During …
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28 lutego 2024 16:15
Robert Simon
Paradoxical colouring rules
A colouring rule is a way to determine a function from a probability space to a set of colours based on the colours of finitely many measure preserving transformations. It is paradoxical if there is …
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24 stycznia 2024 16:15
Taras Banakh (Ivan Franko National University of Lviv and UJK Kielce)
Strongly rigid countable Hausdorff spaces
A topological space $X$ is strongly rigid if every no-identity continuous self-map of $X$ is constant. Among known examples of strongly rigid spaces one can recall the famous Cook continua. In fact, every strongly rigid …
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10 stycznia 2024 16:15
Piotr Szewczak (Cardinal Stefan Wyszyński University in Warsaw)
Concentrated sets in the Miller model
A set of reals X is concentrated if it is uncountable and there is a countable subset D of X such that for each open set U containing D the set X\U is countable. Using …
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20 grudnia 2023 16:15
Zdeněk Silber (IM PAN)
A countably tight P
In the talk we focus on the relation of countable tightness of the space P(K) of Radon probabilty measures on a compact Hausdorff space K and of existence of measures in P(K) that have uncountable …
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13 grudnia 2023 16:15
Maciej Malicki (IM PAN)
Compacta and their homeomorphism groups from posets, part 2
Very recently A. Bartoš, T. Bice and A. Vignati discovered a duality, generalizing the Stone duality, between second countable T_1 compacta and graded omega-posets. Their approach allows for elementary combinatorial constructions, in the spirit of …
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6 grudnia 2023 16:15
Adam Bartoš ("An introduction to abstract Fraïssé theory") and Wiesław Kubiś ("Uncountable homogeneous structures") (Institute of Mathematics of the Czech Academy of Sciences)
"An introduction to abstract Fraïssé theory" and "Uncountable homogeneous structures"
"An introduction to abstract Fraïssé theory": We give a gentle introduction to abstract countable discrete Fraïssé theory. First, we recall three classical examples of ultrahomogeneous structures: the linear order of the rationals, the random graph, …
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29 listopada 2023 16:15
Maciej Malicki (IM PAN)
Compacta and their homeomorphism groups from posets
Very recently A. Bartoš, T. Bice and A. Vignati discovered a duality, generalizing the Stone duality, between second countable T_1 compacta and graded omega-posets. Their approach allows for elementary combinatorial constructions, in the spirit of …
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22 listopada 2023 16:15
Jindrich Zapletal (University of Florida)
Fraenkel-Mostowski models revisited
A dynamical ideal is a group G acting on a set X, together with an ideal I on X invariant under the action. A dynamical ideal comes with an associated model of ZF set theory. …
