Results 61 to 70 of about 581 (209)

Some inequalities involving unitarily invariant norms [PDF]

Mathematical Inequalities & Applications, 2012
This paper aims to present some inequalities for unitarily invariant norms. We first give inverses of Young and Heinz type inequalities for scalars. Then we use these inequalities to establish some inequalities for unitarily invariant norms. Mathematics subject classification (2010): 15A45, 15A60.
Chuanjiang He, Limin Zou
openaire   +1 more source

Countable Basis for Free Electromagnetic Fields

Annalen der Physik, Volume 538, Issue 5, May 2026.
ABSTRACT Polychromatic electromagnetic fields are expanded as integrals over monochromatic fields, such as plane waves, multipolar fields, or Bessel beams. However, monochromatic fields do not belong to the Hilbert space of free Maxwell fields, since their norms diverge.
Ivan Fernandez‐Corbaton
wiley   +1 more source

On weakly unitarily invariant norm and the λ-Aluthge transformation for invertible operator

, 2006
Let T∈B(H) be an invertible operator with polar decomposition T=UP and B∈B(H) commute with T. In this paper we prove that ∣∣∣PλBUP1−λ∣∣∣⩽∣∣∣BT∣∣∣, where ∣∣∣·∣∣∣ is a weakly unitarily invariant norm on B(H) and 0⩽λ⩽1. As the consequence of this result, we
Okubo, Kazuyoshi
core   +1 more source

Maximally dissipative and self‐adjoint extensions of K$K$‐invariant operators

Bulletin of the London Mathematical Society, Volume 58, Issue 5, May 2026.
Abstract We introduce the notion of K$K$‐invariant operators, S$S$, in a Hilbert space, with respect to a bounded and boundedly invertible operator K$K$ defined via K∗SK=S$K^*SK=S$. Conditions such that self‐adjoint and maximally dissipative extensions of K$K$‐invariant symmetric operators are also K$K$‐invariant are investigated.
Christoph Fischbacher, Bart Rosenzweig, Jonathan Stanfill   +2 more
wiley   +1 more source

Operator Monotone Functions and Convexity of Its Derivatives Norms

پژوهش‌های ریاضی, 2021
Introduction  Given the important role convex and quasi-convex functions play in many areas of mathematics and especially in optimization, one of the inequalities that has attracted the attention of many mathematicians in recent decades is Hermit ...
Zahra Rahimi Chegeni, amir ghasem ghazanfari, Kamal Falahi   +2 more
doaj  

Algebraic singular functions are not always dense in the ideal of C∗$C^*$‐singular functions

Bulletin of the London Mathematical Society, Volume 58, Issue 5, May 2026.
Abstract We give the first examples of étale (non‐Hausdorff) groupoids G$\mathcal {G}$ whose C∗$C^*$‐algebras contain singular elements that cannot be approximated by singular elements in Cc(G)$\mathcal {C}_c(\mathcal {G})$. We provide two examples: one is a bundle of groups and the other a minimal and effective groupoid constructed from a self‐similar
Diego Martínez, Nóra Szakács
wiley   +1 more source

Some operator inequalities for unitarily invariant norms [PDF]

, 2005
Let L(H) be the algebra of bounded operators on a complex separable Hilbert space H. Let N be a unitarily invariant norm defined on a norm ideal J ⊆ L(H). Given two positive invertible operators P,Q ∊ L(H) and k ∊ (−2, 2], we show that N (PTQ−1 + P−1TQ +
Mosconi, Irene, Stojanoff, Demetrio, Cano, Cristina   +2 more
core   +1 more source

Quantum Time‐Marching Algorithms for Solving Linear Transport Problems Including Boundary Conditions

International Journal for Numerical Methods in Engineering, Volume 127, Issue 8, 30 April 2026.
ABSTRACT This article presents the first complete application of a quantum time‐marching algorithm for simulating multidimensional linear transport phenomena with arbitrary boundaries, whereby the success probabilities are problem intrinsic. The method adapts the linear combination of unitaries algorithm to block encode the diffusive dynamics, while ...
Sergio Bengoechea, Paul Over, Thomas Rung   +2 more
wiley   +1 more source

Perturbation bounds of {1,3}-and {1,4}- inverses under the unitarily invariant norm(酉不变范数下{1，3}-和{1，4}-逆的扰动界)

Zhejiang Daxue xuebao. Lixue ban, 2018
MENG等给出了 {1，3}-和{1，4}-逆在谱范数和Frobenius范数下的加法和乘法扰动界，本文研究了 {1，3}-和{1,4}-逆在一般的酉不变范数下的加法和乘法扰动界，所得结果推广和改进了已有文献中的相关结果.
MENGLingsheng(孟令胜)
doaj   +1 more source

Non‐Relativistic Limit of Dirac Hamiltonians With Aharonov–Bohm Fields

Studies in Applied Mathematics, Volume 156, Issue 4, April 2026.
ABSTRACT We characterize the families of self‐adjoint Dirac and Schrödinger operators with Aharonov–Bohm magnetic field, and we exploit the non‐relativistic limit of infinite light speed to connect the former to the latter. The limit consists of the customary removal of the rest energy and of a suitable scaling, with the light speed, of the short‐scale
Matteo Gallone, Alessandro Michelangeli, Diego Noja   +2 more
wiley   +1 more source