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A perspective function is a construction which combines a base function defined on a given space with a nonlinear scaling function defined on another space and which yields a lower semicontinuous convex function on the product space. Since…

Optimization and Control · Mathematics 2024-07-08 Luis M. Briceño-Arias , Patrick L. Combettes , Francisco J. Silva

Let $T\colon H^1({\mathbb R})\to H^1({\mathbb R})$ be a bounded Fourier multiplier on the analytic Hardy space $H^1({\mathbb R})\subset L^1({\mathbb R})$ and let $m\in L^\infty({\mathbb R}_+)$ be its symbol, that is,…

Functional Analysis · Mathematics 2025-02-05 Loris Arnold , Christian Le Merdy , Safoura Zadeh

For an operator generating a group on $L^p$ spaces transference results give bounds on the Phillips functional calculus also known as spectral multiplier estimates. In this paper we consider specific group generators which are abstraction…

Functional Analysis · Mathematics 2021-08-25 Himani Sharma

An integral is defined on the plane that includes the Henstock--Kurzweil and Lebesgue integrals (with respect to Lebesgue measure). A space of primitives is taken as the set of continuous real-valued functions $F(x,y)$ defined on the…

Classical Analysis and ODEs · Mathematics 2020-04-30 Erik Talvila

We characterize Hilbert spaces in the class of all Banach spaces using Fourier transform of vector-valued functions over the field $Q_p$ of $p$-adic numbers. Precisely, Banach space $X$ is isomorphic to a Hilbert one if and only if Fourier…

Functional Analysis · Mathematics 2008-08-29 Yauhen Radyna , Yakov Radyno , Anna Sidorik

Let $X$ be a centered Gaussian random variable in a separable Hilbert space ${\mathbb H}$ with covariance operator $\Sigma.$ We study a problem of estimation of a smooth functional of $\Sigma$ based on a sample $X_1,\dots ,X_n$ of $n$…

Statistics Theory · Mathematics 2019-03-05 Vladimir Koltchinskii

We define the frame potential for a Schauder frame on a finite dimensional Banach space as the square of the $2$-summing norm of the frame operator. As is the case for frames for Hilbert spaces, we prove that the frame potential can be used…

Functional Analysis · Mathematics 2018-04-12 J. A. Chávez-Domínguez , D. Freeman , K. Kornelson

In this paper we extend the $H^\infty$ functional calculus to quaternionic operators and to $n$-tuples of noncommuting operators using the theory of slice hyperholomorphic functions and the associated functional calculus, called…

Functional Analysis · Mathematics 2015-11-25 D. Alpay , F. Colombo , T. Qian , I. Sabadini

As objects of study in functional analysis, Hilbert spaces stand out as special objects of study as do nuclear spaces in view of a rich geometrical structure they possess as Banach and Frechet spaces, respectively. On the other hand, there…

Functional Analysis · Mathematics 2013-10-29 M A Sofi

In this paper we consider square functions (also called Littlewood-Paley g-functions) associated to Hankel convolutions acting on functions in the Bochner-Lebesgue space $L^p((0,\infty),B)$, where $B$ is a UMD Banach space. As special cases…

Classical Analysis and ODEs · Mathematics 2016-06-08 Jorge J. Betancor , Alejandro J. Castro , Lourdes Rodriguez-Mesa

In this paper, we first prove that the S-spectrum of a bounded right quaternionic linear operator on a two-sided quaternionic Banach space is a union of the spectrum of some bounded linear operators on a complex Banach space. Furthermore,…

Functional Analysis · Mathematics 2020-05-21 El Hassan Benabdi , Mohamed Barraa

We characterize a holomorphic positive definite function $f$ defined on a horizontal strip of the complex plane as the Fourier-Laplace transform of a unique exponentially finite measure on $\mathbb{R}$. The classical theorems of Bochner on…

Complex Variables · Mathematics 2018-01-30 Jorge Buescu , António Paixão

Suppose -A admits a bounded H-infinity calculus of angle less than pi/2 on a Banach space E with Pisier's property (alpha), let B be a bounded linear operator from a Hilbert space H into the extrapolation space E_{-1} of E with respect to…

Functional Analysis · Mathematics 2014-02-26 Jamil Abreu , Bernhard Haak , Jan van Neerven

Given a unital algebra $\mathscr A$ of locally Lipschitz functions defined over a metric measure space $({\mathrm X},{\mathsf d},\mathfrak m)$, we study two associated notions of function of bounded variation and their relations: the space…

Functional Analysis · Mathematics 2026-04-08 Enrico Pasqualetto , Giacomo Enrico Sodini

A consistent functional calculus approach to the spectral theorem for strongly commuting normal operators on Hilbert spaces is presented. In contrast to the common approaches using projection-valued measures or multiplication operators,…

Functional Analysis · Mathematics 2020-09-28 Markus Haase

We study the stochastic six-vertex model in half-space with generic integrable boundary weights, and define two families of multivariate rational symmetric functions. Using commutation relations between double-row operators, we prove a skew…

Combinatorics · Mathematics 2024-10-08 Alexandr Garbali , Jan de Gier , William Mead , Michael Wheeler

We present here a new method for approximating functions defined on superreflexive Banach spaces by differentiable functions with $\alpha$-H\"older derivatives (for some $0<\alpha\leq 1$). The smooth approximation is given by means of an…

Functional Analysis · Mathematics 2016-09-07 Manuel Cepedello Boiso

We introduce the concept of an $E$-valued function algebra, a type of Banach algebra that consist of continuous $E$-valued functions on some compact Hausdorff space, where $E$ is a Banach algebra. We present some basic results about such…

Functional Analysis · Mathematics 2020-08-12 Azadeh Nikou , Anthony G. O'Farrell

We make some remarks on the global shape of continuous convex functions defined on a Banach space $Z$. Among other results we prove that if $Z$ is separable then for every continuous convex function $f:Z\to\mathbb{R}$ there exist a unique…

Functional Analysis · Mathematics 2020-01-29 Daniel Azagra

The tau function corresponding to the affine ring of a certain plane algebraic curve, called (n,s)-curve, embedded in the universal Grassmann manifold is studied. It is neatly expressed by the multivariate sigma function. This expression is…

Algebraic Geometry · Mathematics 2012-06-01 Atsushi Nakayashiki