November 2022
Arturo Martinez Celis: Some combinatorics related to the Michael space problem III
29/11/22 10:12
Tuesday, November 29, 2022 17:00
Location: room C11-3.11
Speaker: Arturo Martinez Celis
Title: Some combinatorics related to the Michael space problem III
Abstract: In this talk, we will continue the construction of a Michael space from an ultrafilter. We will show the consistency of ZFC + There are no Michael Ultrafilters and we will discuss some open questions.
Location: room C11-3.11
Speaker: Arturo Martinez Celis
Title: Some combinatorics related to the Michael space problem III
Abstract: In this talk, we will continue the construction of a Michael space from an ultrafilter. We will show the consistency of ZFC + There are no Michael Ultrafilters and we will discuss some open questions.
Arturo Antonio Martínez Celis Rodríguez: Some combinatorics related to the Michael space problem II
21/11/22 09:09
Tuesday, November 22, 2022 17:00
Location: room C11-3.11
Speaker: Arturo Antonio Martínez Celis Rodríguez
Title: Some combinatorics related to the Michael space problem II
Abstract: In this talk we will continue the construction of a Michael space from an ultrafilter. The main goal is to show that the existence of a selective ultrafilter (plus \(\varepsilon\ge 0\)) is enough to construct a Michael space. If the time allows it, we will show a model of ZFC without Michael ultrafilters.
Location: room C11-3.11
Speaker: Arturo Antonio Martínez Celis Rodríguez
Title: Some combinatorics related to the Michael space problem II
Abstract: In this talk we will continue the construction of a Michael space from an ultrafilter. The main goal is to show that the existence of a selective ultrafilter (plus \(\varepsilon\ge 0\)) is enough to construct a Michael space. If the time allows it, we will show a model of ZFC without Michael ultrafilters.
Daria Michalik: Blocking properties of the diagonal in Cartesian product
10/11/22 18:54
Tuesday, November 15, 2022 17:00
Location: room C11-3.11
Speaker: Daria Michalik (Jan Kochanowski University in Kielce)
Title: Blocking properties of the diagonal in Cartesian product
Abstract: In [1], the authors present six kinds of blocking properties for points in continua. We can consider the same properties for subcontinua. During my talk I will present some results concerning the blocking properties of the diagonal in Cartesian product. Among others, I will show a new characterisation of the interval.
[1] J. Bobok, P. Pyrih and B. Vejnar, Non-cut, shore and non-block points in continua, Glas. Mat. Ser. III 51 (71) (2016), 237–253.
Location: room C11-3.11
Speaker: Daria Michalik (Jan Kochanowski University in Kielce)
Title: Blocking properties of the diagonal in Cartesian product
Abstract: In [1], the authors present six kinds of blocking properties for points in continua. We can consider the same properties for subcontinua. During my talk I will present some results concerning the blocking properties of the diagonal in Cartesian product. Among others, I will show a new characterisation of the interval.
[1] J. Bobok, P. Pyrih and B. Vejnar, Non-cut, shore and non-block points in continua, Glas. Mat. Ser. III 51 (71) (2016), 237–253.
Damian Głodkowski: A Banach space C(K) reading the dimension of K
08/11/22 05:58
Tuesday, November 8, 2022 17:00
Location: room C11-3.11
Speaker: Damian Głodkowski (University of Warsaw)
Title: A Banach space C(K) reading the dimension of K
Abstract: For every natural number \(n\) I construct (assuming Jensen's diamond principle) a compact space \(K_n\) such that whenever \(L\) is a compact space and the Banach spaces of continuous functions \(C(K_n)\) and \(C(L)\) are isomorphic, the covering dimension of \(L\) is equal to \(n\). The constructed space is a modification of Koszmider's example of a compact space \(K\) with the property that every bounded linear operator \(T\) on \(C(K)\) is a weak multiplication (i.e. it is of the form \(T(f)=gf+S(f)\), where \(g\) is an element of \(C(K_n)\) and \(S\) is weakly compact). In the talk I will give a sketch of the construction and focus on the differences between my and the original space. The talk will be based on https://arxiv.org/abs/2207.00149.
Location: room C11-3.11
Speaker: Damian Głodkowski (University of Warsaw)
Title: A Banach space C(K) reading the dimension of K
Abstract: For every natural number \(n\) I construct (assuming Jensen's diamond principle) a compact space \(K_n\) such that whenever \(L\) is a compact space and the Banach spaces of continuous functions \(C(K_n)\) and \(C(L)\) are isomorphic, the covering dimension of \(L\) is equal to \(n\). The constructed space is a modification of Koszmider's example of a compact space \(K\) with the property that every bounded linear operator \(T\) on \(C(K)\) is a weak multiplication (i.e. it is of the form \(T(f)=gf+S(f)\), where \(g\) is an element of \(C(K_n)\) and \(S\) is weakly compact). In the talk I will give a sketch of the construction and focus on the differences between my and the original space. The talk will be based on https://arxiv.org/abs/2207.00149.