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Author: Anna Pelczar-Barwacz

Michał Popow

Pomeranian University in Słupsk (Poland) and Vasyl Stefanyk Precarpathian National University, IvanoFrankivsk (Ukraine)

Representation theorems for regular operators

[6.03.2024, 12.15] 

[THE MEETING IS HELD ONLINE ONLY]

Please find the abstract here

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Antoni Machowski

Jagiellonian University 

Strongly exposing functionals of convex weakly compact sets

[27.02.2024, 12.15. THE MEETING IS HELD HYBRID, STATIONARY PART in 1016]

Abstract: For a closed, convex bounded subset C of a Banach space X we call a point x in C strongly exposed if some functional on X attains its strong maximum in x. Functionals of norm one that satisfy the above condition for some point in C are called strongly exposing functionals of C. In my talk I will present a proof by J. Bourgain of celebrated results by J. Lindenstrauss and S.L. Troyanski stating that a convex and weakly compact subset of a Banach space is the closed convex hull of its strongly exposed points and the set of strongly exposing functionals of C is a dense G-delta subset of the unit sphere of X*.

References:

J. Lindenstrauss, On operators which attain their norm (1963)

S. L. Trojanski, On locally uniformly convex and differentiable norms in certain non-separable Banach spaces (1970)

J. Bourgain, Strongly exposed points in weakly compact convex sets in Banach spaces (1976)

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Meeting ID: 392 359 686 95

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Seminars in 2023/2034 (Winter term)

24.01.2024 ▴ Jerzy Grzybowski (Adam Mickiewicz University in Poznań):
Maksymalna różnica Demyanova zbiorów wypukłych, a maksymalna ilość punktów ekstremalnych sumy Minkowskiego
 
10.01.2024 ▴ Tomasz Kania:
Lattice points in Banach spaces
 
20.12.2023 ▴ Joanna Garbulińska-Węgrzyn (Jan Kochanowski University of Kielce):
On the Darji Matheron universal operator
 
13.12.2023 ▴ Tomasz Kobos:
Spaces with maximal projection constants revisited
 
6.12.2023 ▴ Mariusz Niwiński:
Indefinite inner product spaces and Dirac operators
 
29.11.2023 ▴ Grzegorz Lewicki:
On two-strongly unique best approximation in the complex case
 
22.11.2023 ▴ Anna Pelczar-Barwacz:
Equivalence of block sequences in Schreier spaces
 
8.11.2023 ▴ Krystian Kazaniecki (Johannes Kepler University Linz):
Schur property for jump parts of gradient measures
 
25.10.2023 ▴ Grzegorz Lewicki:
On the maximal hyperplane in ℓ^p_n
 
18.10.2023 ▴ Hanna Wojewódka-Ściążko (UŚ; PAN):
When asymptotically stable Markov semigroups have the e-property?
 
11.10.2023 ▴ Jerzy Kąkol:
About Banach-Mazur’s problem from the 1930s
 
4.10.2023 ▴ Michał Wojciechowski (Instytut Matematyczny Polskiej Akademii Nauk):
Singular pluriharmonic quaternionic measure
 
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Seminars in 2022/2023

31.05.2023  Tomasz Kochanek (MIMUW):
The Hyers-Ulam property of groups and its connections to group C*-algebras
 
24.05.2023  Tomasz Kobos:
Lower bounds on the norm of linear projection through smoothness
 
17.05.2023  Antoni Machowski:
A generalization of a theorem of Yamabe
 
10.05.2023  Jarosław Swaczyna (Technical University of Łódź):
Slow dynamical systems with large Hausdorff dimension
 
26.04.2023  Anna Pelczar-Barwacz:
Operator ideals on Schreier spaces of arbitrary order
 
19.04.2023  Natalia Maślany (UJ):
Differential embeddings into algebras of topological stable rank 1
 
5.04.2023  Barbara Lewandowska:
On the generalized Grunbaum conjecture (2)
 
22.03.2023  Barbara Lewandowska:
On the generalized Grunbaum conjecture (1)
 
8.03.2023  Tomasz Kobos:
An affine dimension of the set of minimal hyperplane projections
 
25.01.2023  Tomasz Kania:
Isometries of combinatorial Tsirelson spaces
 
18.01.2023  Grzegorz Lewicki:
Minimal projections onto subspaces generated by sign matrices (2)
 
11.01.2023  Grzegorz Lewicki:
Minimal projections onto subspaces generated by sign matrices (1)
 
14.12.2022  Krzysztof Ciosmak (University of Oxford, Fields Institute, University of Toronto):
Multi-dimensional localisation and 1-Lipschitz maps
 
7.12.2022  Natalia Maślany:
Isometries of combinatorial Tsirelson spaces
 
30.11.2022  Tomasz Kobos:
On the affine dimension of the set of minimal projections (4)
 
23.11.2022  Tomasz Kobos:
On the affine dimension of the set of minimal projections (3)
 
16.11.2022  Bence Horváth (Institute of Mathematics of the Czech Academy of Sciences):
Ring-theoretic (in)finiteness in ultraproducts of Banach algebras
 
9.11.2022  Anna Pelczar-Barwacz:
A Banach space with an infinite-dimensional reflexive quotient algebra L(X)/SS(X)
 
26.10.2022  Tomasz Kobos:
On the affine dimension of the set of minimal projections (2)
 
19.10.2022  Andrzej Kryczka (UMCS):
Regularne metody sumowania dla sum prostych i przestrzeni interpolacyjnych
 
12.10.2022  Tomasz Kobos:
On the affine dimension of the set of minimal projections (1)
 
5.10.2022  Spotkanie organizacyjne 
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