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Related papers: Diameter two properties, convexity and smoothness

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In this paper, we investigate the relationship between the weak min-max property and the diameter uniformity of domains in Banach spaces with dimensions at least $2$. As an application, we show that diameter uniform domains are invariant…

Complex Variables · Mathematics 2021-04-27 Zhengyong Ouyang , Antti Rasila , Tiantian Guan

In this work we study three different versions of small diameter properties of the unit ball in a Banach space and its dual. The related concepts for all closed bounded convex sets of a Banach space was initiated and developed in \cite{B3},…

Functional Analysis · Mathematics 2021-08-21 Sudeshna Basu , Susmita Seal

A Banach space has the weak fixed point property if its dual space has a weak$^*$ sequentially compact unit ball and the dual space satisfies the weak$^*$ uniform Kadec-Klee property; and it has the \fpp if there exists $\epsilon>0$ such…

Functional Analysis · Mathematics 2008-04-04 P. N. Dowling , B. Randrianantoanina , B. Turett

In this paper, we study several variants of Hahn-Banach smoothness, viz., property-$(SU)$/$(HB)$/$(wU)$, where property-$(SU)$ and property-$(HB)$ are stronger notions and property-$(wU)$ is a weaker notion of Hahn-Banach smoothness. We…

Functional Analysis · Mathematics 2024-03-07 Soumitra Daptari

We show that every Banach space containing isomorphic copies of $c_0$ can be equivalently renormed so that every nonempty relatively weakly open subset of its unit ball has diameter 2 and, however, its unit ball still contains convex…

Functional Analysis · Mathematics 2014-10-17 Julio Becerra Guerrero , Ginés López-Pérez , Abraham Rueda Zoca

We prove that the following three properties for a Banach space are all different from each other: every finite convex combination of slices of the unit ball is (1) relatively weakly open, (2) has nonempty interior in relative weak topology…

Functional Analysis · Mathematics 2017-03-10 Rainis Haller , Paavo Kuuseok , Märt Põldvere

We study properties of quasihyperbolic geodesics on Banach spaces. For example, we show that in a strictly convex Banach space with the Radon-Nikodym property, the quasihyperbolic geodesics are unique. We also give an example of a convex…

Complex Variables · Mathematics 2014-06-18 Antti Rasila , Jarno Talponen

In this paper, we study the coarse Lipschitz geometry of Banach spaces with several asymptotic properties. Specifically, we look at asymptotically uniformly smoothness and convexity, and several distinct Banach-Saks-like properties. Among…

Functional Analysis · Mathematics 2017-02-17 Bruno de Mendonça Braga

A Banach space $X$ has the $2$-summing property if the norm of every linear operator from $X$ to a Hilbert space is equal to the $2$-summing norm of the operator. Up to a point, the theory of spaces which have this property is independent…

Functional Analysis · Mathematics 2016-09-06 Alvaro Arias , Tadek Figiel , William B. Johnson , Gideon Schechtman

We analyze smooth nonlinear mappings for Hilbert and Banach spaces that carry small balls to convex sets, provided that the radius of the balls is small enough. Being focused on the study of new and mild sufficient conditions for a…

Functional Analysis · Mathematics 2024-03-18 Yarema A. Prykarpatskyy , Petro Ya. Pukach , Myroslava I. Vovk , Michal Greguš

In this paper, we study different kinds of normal properties for infinite system of arbitrarily many convex sets in a Banach space and provide the dual characterization for the normal property in terms of the extended Jamenson property for…

Optimization and Control · Mathematics 2017-03-14 Zhou Wei , Qinghai He

We characterize the points of $\left\|\cdot\right\|$-$w^*$ continuity of dual maps, turning out to be the smooth points. We prove that a Banach space has the Schur property if and only if it has the Dunford-Pettis property and there exists…

Functional Analysis · Mathematics 2015-10-07 Francisco J. García-Pacheco , Alejandro Miralles , Daniele Puglisi

We introduce stronger versions of the usual notions of martingale type p <= 2 and cotype q >= 2 of a Banach space X and show that these concepts are equivalent to uniform p-smoothness and q-convexity, respectively. All these are metric…

Functional Analysis · Mathematics 2007-05-23 Jörg Wenzel

In this paper we study very smooth points of Banach spaces with special emphasis on spaces of operators. We show that when the space of compact operators is an $M$-ideal in the space of bounded operators, a very smooth operator $T$ attains…

Functional Analysis · Mathematics 2007-05-23 T. S. S. R. K. Rao

In this short note, we study two different geometrical aspects of Banach spaces with small diameter properties, namely the Ball Dentable Property (BDP), Ball Huskable Property (BHP) and Ball Small Combination of slice Property (BSCSP). We…

Functional Analysis · Mathematics 2023-07-18 Sudeshna Basu , Susmita Seal

In [2] we characterized in terms of a quadratic growth condition various metric regularity properties of the subdifferential of a lower semicontinuous convex function acting in a Hilbert space. Motivated by some recent results in [16] where…

Optimization and Control · Mathematics 2015-07-01 Francisco J. Aragón Artacho , Michel H. Geoffroy

We study a uniform version of the strong diameter two property. In particular, we find a characterisation that does not involve ultrafilters and we use it to provide some examples of spaces with this uniform property that do not follow from…

Functional Analysis · Mathematics 2025-12-15 Esteban Martínez Vañó , Abraham Rueda Zoca

We find conditions for a smooth nonlinear map $f:U\rightarrow V$ between open subsets of Hilbert or Banach spaces to be locally convex in the sense that for some $c$ and each positive $\varepsilon<c$ the image $% f(B_\varepsilon(x))$ of…

Functional Analysis · Mathematics 2012-05-16 Iryna Banakh , Taras Banakh , Anatolij Plichko , Anatoliy Prykarpatsky

We show that there exists a Banach space in which every non-empty weakly open subset of its unit ball has radius one, the maximum possible value, but the infimum of the diameter of its slices is exactly one, so extremely far from its…

Functional Analysis · Mathematics 2025-10-20 Ginés López-Pérez , Esteban Martínez Vañó , Abraham Rueda Zoca

We study dentable maps from a closed convex subset of a Banach space into a metric space as an attempt of generalize the Radon-Nikod\'ym property to a "less linear" frame. We note that a certain part of the theory can be developed in rather…

Functional Analysis · Mathematics 2017-06-01 Luis García-Lirola , Matías Raja