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We consider optimization algorithms that are open systems, that is, with external inputs and outputs. Such algorithms arise for instance, when analyzing the effect of noise or disturbance on an algorithm, or when an algorithm is part of…

Optimization and Control · Mathematics 2026-04-02 Jaap Eising , Florian Dörfler

In this paper, we introduce operator geodesically convex and operator convex-log functions and characterize some properties of them. Then apply these classes of functions to present several operator Azc\'{e}l and Minkowski type inequalities…

Functional Analysis · Mathematics 2020-04-07 V. Kaleibary , M. R. Jabbarzadeh , S. Furuichi

We obtain generalisations of some inequalities for positive unital linear maps on matrix algebra. This also provides several positive semidefinite matrices and we get some old and new inequalities involving the eigenvalues of a Hermitian…

Functional Analysis · Mathematics 2016-02-16 R. Sharma , P. Devi , R. kumari

The main target of this paper is to discuss operator Hermite--Hadamard inequality for convex functions, without appealing to operator convexity. Several forms of this inequality will be presented and some applications including norm and…

Functional Analysis · Mathematics 2019-08-07 Hamid Reza Moradi , Mohammad Sababheh , Shigeru Furuichi

Some properties and relations satisfied by the polynomial solutions of the bispectral problem are studied. Given a differential operator, under certain restrictions its polynomial eigenfunctions are explicitly obtained, as well as the…

Spectral Theory · Mathematics 2021-11-30 D. Barrios Rolanía

We give a formula for matrix exponentials and partial fraction decompositions.

General Mathematics · Mathematics 2007-05-23 Pierre-Yves Gaillard

In this paper, we establish some upper bounds for numerical radius inequalities including of $2\times 2$ operator matrices and their off-diagonal parts. Among other inequalities, it is shown that if $T=\left[\begin{array}{cc} 0&X, Y&0…

Functional Analysis · Mathematics 2018-11-14 Mojtaba Bakherad , Khalid Shebrawi

In this paper we {\em discuss} diverse aspects of mutual relationship between adjoints and formal adjoints of unbounded operators bearing a matrix structure. We emphasize on the behaviour of row and column operators as they turn out to be…

Functional Analysis · Mathematics 2007-06-18 M. Möller , F. H. Szafraniec

Scaling problems have a rich and diverse history, and thereby have found numerous applications in several fields of science and engineering. For instance, the matrix scaling problem has had applications ranging from theoretical computer…

Data Structures and Algorithms · Computer Science 2018-08-30 Ankit Garg , Rafael Oliveira

We describe recent work of Kim in arXiv:1210.5190 to show that operator convex functions associated with quasi-entropies can be used to prove a large class of new matrix inequalities in the tri-partite and bi-partite setting by taking a…

Quantum Physics · Physics 2015-06-12 Mary Beth Ruskai

A matrix-compression algorithm is derived from a novel isogenic block decomposition for square matrices. The resulting compression and inflation operations possess strong functorial and spectral-permanence properties. The basic observation…

Rings and Algebras · Mathematics 2022-11-01 Alexander Belton , Dominique Guillot , Apoorva Khare , Mihai Putinar

We prove inequalities on symmetric tensor sums of positive definite operators. In particular, we prove multivariable operator inequalities inspired by generalizations to the well-known Hlawka and Popoviciu inequalities. As corollaries, we…

Functional Analysis · Mathematics 2014-11-18 Wolfgang Berndt , Suvrit Sra

General approach to the multiplication or adjoint operation of $2\times 2$ block operator matrices with unbounded entries are founded. Furthermore, criteria for self-adjointness of block operator matrices based on their entry operators are…

Functional Analysis · Mathematics 2014-04-01 Guohai Jin , Alatancang Chen

We consider convex trace functions $\Phi_{p,q,s} = Trace[ (A^{q/2}B^p A^{q/2})^s]$ where $A$ and $B$ are positive $n\times n$ matrices and ask when these functions are convex or concave. We also consider operator convexity/concavity of…

Mathematical Physics · Physics 2015-07-15 Eric A. Carlen , Rupert L. Frank , Elliott H. Lieb

In this paper we present 43 new inequalities related to integer part and fractional part.

General Mathematics · Mathematics 2007-11-06 Mihaly Bencze , Florentin Smarandache

In this note we devise and analyse well-posed variational formulations and operator theoretical methods for boundary value problems associated to the biharmonic operator. Of particular interest are Neumann type and over- and underdetermined…

Analysis of PDEs · Mathematics 2025-12-02 Dirk Pauly , Alberto Valli

In this survey article we discuss key open problems which could serve as a guidance for further research directions of multiplicative ideal theory and factorization theory.

Commutative Algebra · Mathematics 2026-03-03 Alfred Geroldinger , Hwankoo Kim , K. Alan Loper

In this paper we introduce operator s-convex func- tions and establish some Hermite-Hadamard type inequalities in which some operator s-convex functions of positive operators in Hilbert spaces are involved.

Functional Analysis · Mathematics 2014-07-10 Amir Ghasem Ghazanfari

This article aims to explore the most recent developments in the study of the Hilbert matrix, acting as an operator on spaces of analytic functions and sequence spaces. We present the latest advances in this area, aiming to provide a…

Functional Analysis · Mathematics 2024-11-04 Carlo Bellavita , Vassilis Daskalogiannis , Georgios Stylogiannis

We consider matrix problems in Hilbert spaces (orthoscalar representations of quivers and posets). A criterion of tameness of the problem of classification of indecomposable orthoscalar representations of a quiver is given.

Representation Theory · Mathematics 2007-05-23 A. V. Roiter , S. A. Kruglyak , L. A. Nazarova