Cotygodniowe seminarium badawcze
2018-11-21, godz. 16:15, 5050
Grzegorz Plebanek (University of Wrocław)
On Cartesian products of compact lines
This is joint work with Gonzalo Martinez Cervantes. By a compact line we mean a compact space which topology is defined by a linear order. Answering a problem posed by Mardesic, we show that n-fold product of compact lines cannot be continuously mapped onto a product of n+1 nonmetrizable spaces. ...
2018-11-14, godz. 16:15, 5050
Arturo Antonio Martínez Celis Rodríguez (IMPAN)
Ultrafilters related to the Michael space problem
A Lindelöf Topological space is Michael if it has non-Lindelöf product with the space of the irrational numbers. These kind of spaces were introduced by Ernest Michael in 1963 and it is still unknown if one can be constructed in ZFC. We will introduce the notion of Michael ultrafilter and we will ...
2018-11-07, godz. 16:15, 5050
Ali Enayat (University of Gothenburg, Sweden)
Models of arithmetic meet set theory and topology
The first part of the talk is expository and provides a general introduction to nonstandard models of arithmetic, and the various ways they interact with set theory and topology. The second part focuses on recent results obtained in collaboration with Joel David Hamkins and Bartosz Wcisło on...
2018-10-24, godz. 16:15, 5050
Paweł Krupski (Wrocław University of Science and Technology)
Complexity of homeomorphism relations on some classes of compacta
This is a joint work with Benjamin Vejnar (https://arxiv.org/pdf/1808.08760.pdf). We prove that the homeomorphism relation between compact spaces can be continuously reduced to the homeomorphism equivalence relation between absolute retracts which strengthens and simplifies recent results of Chan...
2018-10-17, godz. 16:15, 5050
Roman Pol (University of Warsaw)
On a problem of Talagrand concerning separately continuous functions
This is a joint work with Volodymyr Mykhaylyuk (a preliminary version of our paper is on arXiv: https://arxiv.org/pdf/1809.05799.pdf) M.Talagrand [Math.Ann.270(1985),Probleme 3] stated the following problem (recalled recently in Guirao, V.Montesinos, V.Zizler, Open problems in geometry and ...
2018-10-10, godz. 16:15, 5050
Viktoriia Brydun (Lviv National University)
Fuzzy metrization of the spaces of idempotent measures
The talk will be dedicated to idempotent mathematics (better known as tropical mathematics) and category theory. The idempotent measures (Maslov measures) are counterparts of the probability measures in the idempotent mathematics. The main result provides a fuzzy metrization ...
2018-06-13, godz. 16:15, 5050
Kazimierz Alster (UKSW)
Gra Telgarskiego a multiplikatywność parazwartości
Ogólnym problemem dotyczącym multiplikatywności parazwartości jest pytanie o charakteryzację klasy P przestrzeni parazwartych, których iloczyn kartezjański z dowolną przestrzenią parazwartą jest parazwarty a także związane z nim problemy: Czy klasa P jest zamknięta ze względu na dom...
2018-06-06, godz. 16:15, 5050
Piotr Szewczak (Cardinal Stefan Wyszyński University in Warsaw)
Products of Luzin-type sets with combinatorial properties
A topological space is Menger if for any sequence U1, U2, … of open covers of the space, there are finite subsets F1, F2, … of U1, U2, …, respectively, such that the union of F1, F2, … covers the space. If we can request that the sets F1, F2, … are singletons, then the space is Rothberger....
2018-05-23, godz. 16:15, 5050
Kazimierz Alster (UKSW)
Gra Telgarskiego a multiplikatywność parazwartości
Ogólnym problemem dotyczącym multiplikatywności parazwartości jest pytanie o charakteryzację klasy P przestrzeni parazwartych, których iloczyn kartezjański z dowolną przestrzenią parazwartą jest parazwarty a także związane z nim problemy: Czy klasa P jest zamknięta ze wzgl...
2018-05-16, godz. 16:15, 5050
Julien Melleray (Institut Camille Jordan, Université Lyon 1)
Full groups of minimal homeomorphisms of the Cantor space
The first part of the talk will be an introduction to the theory of minimal homeomorphisms and their full groups (and why these objects are interesting). In the second talk I'll sketch the proof of the following result (joint with T. Ibarlucia): the full group of any minimal homeomorphism is a coana...