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Related papers: Daugavet property in tensor product spaces

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We investigate rich subspaces of $L_1$ and deduce an interpolation property of Sidon sets. We also present examples of rich separable subspaces of nonseparable Banach spaces and we study the Daugavet property of tensor products.

Functional Analysis · Mathematics 2011-03-17 Vladimir Kadets , Nigel Kalton , Dirk Werner

A $\Delta$-point $x$ of a Banach space is a norm one element that is arbitrarily close to convex combinations of elements in the unit ball that are almost at distance $2$ from $x$. If, in addition, every point in the unit ball is…

Functional Analysis · Mathematics 2018-12-07 Trond Arnold Abrahamsen , Rainis Haller , Vegard Lima , Katriin Pirk

In contrast with 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 vectors in $X^{**}$ being $L$-orthogonal to $X$,…

Functional Analysis · Mathematics 2020-09-22 Ginés López-Pérez , Abraham Rueda Zoca

We introduce the super alternative Daugavet property (super ADP) which lies strictly between the Daugavet property and the Alternative Daugavet property as follows. A Banach space $X$ has the super ADP if for every element $x$ in the unit…

Functional Analysis · Mathematics 2026-04-15 Johann Langemets , Marcus Lõo , Miguel Martín , Yoël Perreau , Abraham Rueda Zoca

Let $X$ be a Banach space. We introduce a formal approach which seems to be useful in the study of those properties of operators on $X$ which depend only on the norms of images of elements. This approach is applied to the Daugavet equation…

Functional Analysis · Mathematics 2007-05-23 Vladimir Kadets , Roman Shvidkoy , Dirk Werner

We show that $W^{1,1}(\mathbb{R}^2)$ has the Daugavet property when endowed with the norm induced by the $L^1$-norm of the gradient, but fails to have the slice diameter two property when equipped with the usual Sobolev norm.

Functional Analysis · Mathematics 2026-01-30 Samir Hamad

We show that the duals of Banach algebras of scalar-valued bounded holomorphic functions on the open unit ball $B_E$ of a Banach space $E$ lack weak$^*$-strongly exposed points. Consequently, we obtain that some Banach algebras of…

Functional Analysis · Mathematics 2023-03-27 Mingu Jung

We consider a certain type of geometric properties of Banach spaces, which includes for instance octahedrality, almost squareness, lushness and the Daugavet property. For this type of properties, we obtain a general reduction theorem,…

Functional Analysis · Mathematics 2017-11-27 Jan-David Hardtke

We study the existence of Daugavet- and delta-points in the unit sphere of Banach spaces with a $1$-unconditional basis. A norm one element $x$ in a Banach space is a Daugavet-point (resp. delta-point) if every element in the unit ball…

Functional Analysis · Mathematics 2020-07-10 Trond A. Abrahamsen , Vegard Lima , André Martiny , Stanimir Troyanski

We introduce two new notions called the Daugavet constant and $\Delta$-constant of a point, which measure quantitatively how far the point is from being Daugavet point and $\Delta$-point and allow us to study Daugavet and $\Delta$-points in…

Functional Analysis · Mathematics 2024-12-18 Geunsu Choi , Mingu Jung

A natural extension of the Daugavet property for $p$-convex Banach function spaces and related classes is analysed. As an application, we extend the arguments given in the setting of the Daugavet property to show that no reflexive space…

Functional Analysis · Mathematics 2015-07-16 Enrique A. Sanchez Perez , Dirk Werner

For a compact metric space $K$ the space $\Lip(K)$ has the Daugavet property if and only if the norm of every $f \in \Lip(K)$ is attained locally. If $K$ is a subset of an $L_p$-space, $1<p<\infty$, this is equivalent to the convexity of…

Functional Analysis · Mathematics 2011-03-17 Yevgen Ivakhno , Vladimir Kadets , Dirk Werner

We prove that there exists a finite-dimensional Banach space $X$ such that $L_1^\mathbb C([0,1])\widehat{\otimes}_\varepsilon X$ fails the strong diameter two property and $L_\infty^\mathbb C([0,1])\widehat{\otimes}_\pi X^*$ fails to have…

Functional Analysis · Mathematics 2024-06-21 Abraham Rueda Zoca

We introduce a new diametral notion for points of the unit sphere of Banach spaces, that naturally complements the notion of Delta-points, but is weaker than the notion of Daugavet points. We prove that this notion can be used to provide a…

Functional Analysis · Mathematics 2023-03-14 Rainis Haller , Johann Langemets , Yoël Perreau , Triinu Veeorg

The aim of this note is to provide several variants of the diameter two properties for Banach spaces. We study such properties looking for the abundance of diametral points, which holds in the setting of Banach spaces with the Daugavet…

Functional Analysis · Mathematics 2016-04-18 Julio Becerra Guerrero , Ginés López Pérez , Abraham Rueda Zoca

We show that the numerical index of any operator ideal is less than or equal to the minimum of the numerical indices of the domain and the range. Further, we show that the numerical index of the ideal of compact operators or the ideal of…

Functional Analysis · Mathematics 2020-05-27 Miguel Martín , Javier Merí , Alicia Quero

A Banach space $X$ has the Daugavet property if the Daugavet equation $\|\Id + T\|= 1 + \|T\|$ holds for every rank-one operator $T:X \longrightarrow X$. We show that the most natural attempts to introduce new properties by considering…

Functional Analysis · Mathematics 2008-11-26 Vladimir Kadets , Miguel Martin , Javier Meri

A Banach space $X$ is said to have the alternative Daugavet property if for every (bounded and linear) rank-one operator $T:X\longrightarrow X$ there exists a modulus one scalar $\omega$ such that $\|Id + \omega T\|= 1 + \|T\|$. We give…

Functional Analysis · Mathematics 2007-05-23 Miguel Martin

We introduce and analyse the notion of slice continuity between operators on Banach spaces in the setting of the Daugavet property. It is shown that under the slice continuity assumption the Daugavet equation holds for weakly compact…

Functional Analysis · Mathematics 2015-07-16 Enrique A. Sánchez Pérez , Dirk Werner

We continue the investigation of the behaviour of diameter two properties in tensor products of Banach spaces. Our main result shows that the symmetric strong diameter two property is stable by taking projective tensor products. We also…

Functional Analysis · Mathematics 2020-03-24 Johann Langemets