L-orthogonality, octahedrality and Daugavet property in Banach spaces

G López-Pérez, AR Zoca - Advances in Mathematics, 2021 - Elsevier
In contrast to the separable case, we prove that the existence of almost L-orthogonal vectors
in a nonseparable Banach space X (octahedrality) does not imply the existence of nonzero …

Computing Borel complexity of some geometrical properties in Banach spaces

G López-Pérez, EM Vañó, AR Zoca - arXiv preprint arXiv:2404.19457, 2024 - arxiv.org
We compute the Borel complexity of some classes of Banach spaces such as different
versions of diameter two properties, spaces satisfying the Daugavet equation or spaces with …

A characterization of Banach spaces containing ℓ1(κ) via ball-covering properties

S Ciaci, J Langemets, A Lissitsin - Israel Journal of Mathematics, 2023 - Springer
In 1989, G. Godefroy proved that a Banach space contains an isomorphic copy of ℓ1 if and
only if it can be equivalently renormed to be octahedral. It is known that octahedral norms …

Banach spaces which always produce octahedral spaces of operators

A Rueda Zoca - Collectanea Mathematica, 2024 - Springer
We characterise those Banach spaces X which satisfy that L (Y, X) is octahedral for every
non-zero Banach space Y. They are those satisfying that, for every finite dimensional …

[HTML][HTML] Almost square dual Banach spaces

TA Abrahamsen, P Hájek, S Troyanski - Journal of Mathematical Analysis …, 2020 - Elsevier
We show that finite dimensional Banach spaces fail to be uniformly non locally almost
square. Moreover, we construct an equivalent almost square bidual norm on ℓ∞. As a …

[HTML][HTML] Octahedrality and Gâteaux smoothness

C Cobollo, P Hájek - Journal of Mathematical Analysis and Applications, 2025 - Elsevier
We prove that every Banach space admitting a Gâteaux smooth norm and containing a
complemented copy of ℓ 1 has an equivalent renorming which is simultaneously Gâteaux …

Octahedral norms in free Banach lattices

S Dantas, G Martínez-Cervantes… - Revista de la Real …, 2021 - Springer
In this paper, we study octahedral norms in free Banach lattices FBL E generated by a
Banach space E. We prove that if E is an L_1 (μ) L 1 (μ)-space, a predual of von Neumann …

Dual and bidual octahedral norms in Lipschitz-free spaces

J Langemets, AR Zoca - arXiv preprint arXiv:1905.09061, 2019 - mat.ucm.es
We continue with the study of octahedral norms in the context of spaces of Lipschitz
functions and in their duals. First, we prove that the norm of J (M)∗∗ is octahedral as soon …

[PDF][PDF] Bidual octahedral renormings in Banach spaces

J Langemets - 2019 - johannlangemets.wordpress.com
Bidual octahedral renormings in Banach spaces Page 1 Bidual octahedral renormings in Banach
spaces Johann Langemets University of Tartu, Estonia April 30th, 2019 Granada, Spain Page …