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Seminarium „Topologia i teoria mnogości”

Cotygodniowe seminarium badawcze


Organizatorzy

Informacje

środy, 16:15 , sala: 5050

Dziedziny badań

Lista referatów

  • 17 października 2018 16:15
    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 …

  • 10 października 2018 16:15
    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 …

  • 13 czerwca 2018 16:15
    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 …

  • 6 czerwca 2018 16:15
    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 …

  • 23 maja 2018 16:15
    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 …

  • 16 maja 2018 16:15
    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 …

  • 9 maja 2018 16:15
    Rafał Filipów (University of Gdańsk)
    Ideal convergence versus matrix summability
    Ideal convergence and matrix summability are examples of extensions of the ordinary convergence of sequences of reals to a larger class of sequences (i.e. ordinary convergent sequences remain convergent to the same limits and there …

  • 25 kwietnia 2018 16:15
    Andrzej Szymański (Cardinal Stefan Wyszyński University in Warsaw)
    KKM Theorem: From L*-operators to a Renting Problem

  • 11 kwietnia 2018 16:15
    Roman Pol (University of Warsaw)
    On a paper by M.V.Ferrer, S.Hernandez and D.Shakhmatov "A countable free closed non-reflexive subgroup of Z^continuum", Proc.AMS 145(2017).
    An abelian topological group H is (Pontrjagin) reflexive if the natural homomorphism from H into the group H^^ of characters on the group of characters on H is a homeomorphism of H onto H^^ (as …

  • 21 marca 2018 16:15
    Piotr Szewczak (Cardinal Stefan Wyszyński University in Warsaw)
    The Haar measure problem
    An old problem asks whether every compact group has a Haar-nonmeasurable subgroup. A series of earlier results reduce the problem to infinite metrizable profinite groups. We provide a positive answer, assuming a weak, potentially provable, …

  • 14 marca 2018 16:15
    Ralf Schindler (Department for Mathematical Logic and Foundational Research, University of Munster)
    "Paradoxical" sets with no well-ordering of the reals
    By a Hamel basis we mean a basis for the reals, R, construed as a vecor space over the field of rationals. In 1905, G. Hamel constructed such a basis from a well-ordering of R. …

  • 7 marca 2018 16:15
    Witold Marciszewski (University of Warsaw)
    On zero-dimensional subspaces of Eberlein compacta
    Let us recall that a compact space K is Eberlein compact if it can be embedded into some Banach space X equipped with the weak topology. We will discuss the following problem: Does every nonmetrizable …

  • 28 lutego 2018 16:15
    TOMASZ NATKANIEC (University of Gdańsk)
    PERFECTLY EVERYWHERE SURJECTIVE BUT NOT JONES FUNCTIONS
    Given a function f : R → R we say that • f is perfectly surjective (f ∈ PES) if f[P] = R for every perfect set P; • f is a Jones function (f …

  • 24 stycznia 2018 16:15
    Taras Banakh (Lviv National University and UJK Kielce)
    Null-finite sets in metric groups and their applications
    We shall introduce a new family of "small" sets which is tightly connected with two well known $\sigma$-ideals: of Haar-null sets and of Haar-meager sets. We define a subset $A$ of a topological group $X$ …

  • 17 stycznia 2018 16:15
    Szymon Żeberski (Wrocław University of Technology)
    Nonmeasurable sets and unions with respect to tree ideals
    We consider a notion of nonmeasurablity with respect to Marczewski and Marczewski-like tree ideals $s_0$, $m_0$, $l_0$, and $cl_0$. We show that there exists a subset $A$ of the Baire space $\omega^\omega$ which is $s$-, …