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Related papers: Modulus of convexity for operator convex functions

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In this article we show the following result: if $C$ is an $n$-dimensional convex and compact subset, $f:C\rightarrow[0,\infty)$ is concave, and $\phi:[0,\infty)\rightarrow[0,\infty)$ is a convex function with $\phi(0)=0$, we then…

Functional Analysis · Mathematics 2021-01-29 Bernardo González Merino

We analyze the role played by $n$-convexity for the fulfillment of a series of linear functional inequalities that extend the Hornich-Hlawka functional inequality, $f\left( x\right) +f\left( y\right) +f\left( z\right) +f\left( x+y+z\right)…

Functional Analysis · Mathematics 2023-01-23 Constantin P. Niculescu , Suvrit Sra

Let $f \geq 0$ be operator monotone on $[0, \infty)$. In this paper we prove that for any unitarily-invariant norm $|||-|||$ on $M_n(\mathbb{C})$ and matrices $A, B, X \in M_n(\mathbb{C})$ with $A, B \geq 0$ and $|||X||| \leq 1$,…

Functional Analysis · Mathematics 2023-11-30 David Herrera

In this article, we employ a standard convex argument to obtain new and refined inequalities related to the matrix mean of two accretive matrices, the numerical radius and the Tsallis relative operator entropy.

Functional Analysis · Mathematics 2021-04-28 Hamid Reza Moradi , Shigeru Furuichi , Mohammad Sababheh

In recent years, the log-concavity or log-convexity of combinatorial sequences and their root sequences, higher order Tur{\'a}n inequalities, and Laguerre inequalities of order two have been widely studied. However, the research of the…

Combinatorics · Mathematics 2025-06-25 Zhongjie Li

A considerable amount of literature in the theory of inequality is devoted to the study of Jensen's and Young's inequality. This article presents a number of new inequalities involving the log-convex functions and the geometrically convex…

Classical Analysis and ODEs · Mathematics 2022-02-10 Shigeru Furuichi , Hamid Reza Moradi , Supriyo Dutta

For a real-valued non-negative and log-concave function we introduce a notion of difference function; the difference function represents a functional analog on the difference body of a convex body. We prove a sharp inequality which bounds…

Metric Geometry · Mathematics 2007-05-23 Andrea Colesanti

Abstract convexity generalises classical convexity by considering the suprema of functions taken from an arbitrarily defined set of functions. These are called the abstract linear (abstract affine) functions. The purpose of this paper is to…

Optimization and Control · Mathematics 2025-01-30 Reinier Diàz Millàn , Nadezda Sukhorukova , Julien Ugon

This paper presents a unified analysis for the proximal subgradient method (Prox-SubGrad) type approach to minimize an overall objective of $f(x)+r(x)$, subject to convex constraints, where both $f$ and $r$ are weakly convex, nonsmooth, and…

Optimization and Control · Mathematics 2026-01-23 Daoli Zhu , Lei Zhao , Shuzhong Zhang

The softmax function is a ubiquitous component at the output of neural networks and increasingly in intermediate layers as well. This paper provides convex lower bounds and concave upper bounds on the softmax function, which are compatible…

Machine Learning · Computer Science 2023-03-06 Dennis Wei , Haoze Wu , Min Wu , Pin-Yu Chen , Clark Barrett , Eitan Farchi

The main theorem of this paper states that the c-convexity and the alternative c-convexity are equivalent if and only if the cost function c satisfies MTW condition. The alternative c-convex function is an analogy of the definition of the…

Optimization and Control · Mathematics 2025-10-08 Seonghyeon Jeong

It is well known that increasing functions do not preserve operator order in general; nor do decreasing functions reverse operator order. However, operator monotone increasing or operator monotone decreasing do. In this article, we employ a…

Functional Analysis · Mathematics 2021-02-16 Gholamreza Karamali , Hamid Reza Moradi , Mohammad Sababheh

In this article, we further explore convex functions by revealing new bounds, resulting from stronger convexity behavior. In particular, we define the so called radical convex functions and study their properties. We will see that such…

Functional Analysis · Mathematics 2020-10-13 Mohammad Sababheh , Hamid Reza Moradi

In this paper, we introduce the concept of operator geometrically convex functions for positive linear operators and prove some Hermite-Hadamard type inequalities for these functions. As applications, we obtain trace inequalities for…

Functional Analysis · Mathematics 2015-08-14 Ali Taghavi , Vahid Darvish , Haji Mohammad Nazari , Sever S. Dragomir

It is known that the function $f(e^x)/g(e^x)$ is positive definite for some functions $f,g$ implies the operator norm inequality related to $f,g$. We treat functions which have the following form: $f(t) = t^{(1-\sum_{i=1}^n…

Functional Analysis · Mathematics 2016-10-25 Imam Nugraha Albania , Masaru Nagisa

In this note we provide a full conjugacy and subdifferential calculus for convex convex-composite functions in finite-dimensional space. Our approach, based on infimal convolution and cone-convexity, is straightforward and yields the…

Optimization and Control · Mathematics 2019-08-22 James V. Burke , Tim Hoheisel , Quang V. Nguyen

In this article, we present a new subadditivity behavior of convex and concave functions, when applied to Hilbert space operators. For example, under suitable assumptions on the spectrum of the positive operators $A$ and $B$, we prove that…

Functional Analysis · Mathematics 2019-04-29 Hamid Reza Moradi , Zahra Heydarbeygi , Mohammad Sababheh

In this study, Firstly, we will write two new convex functions for $-1<n-\alpha \leq 1\ $and two new lemmas. Then we will find the relevance of the two new lemmas to Caputo-left-sided derivatives under additional conditions and draw…

Functional Analysis · Mathematics 2024-07-24 M. Emin Özdemir

We introduce the notion of Krein-operator convexity in the setting of Krein spaces. We present an indefinite version of the Jensen operator inequality on Krein spaces by showing that if $(\mathscr{H},J)$ is a Krein space, $\mathcal{U}$ is…

Functional Analysis · Mathematics 2014-11-04 M. S. Moslehian , M. Dehghani

We propose a notion of operator monotonicity for functions of several variables, which extends the well known notion of operator monotonicity for functions of only one variable. The notion is chosen such that a fundamental relationship…

Operator Algebras · Mathematics 2007-05-23 Frank Hansen