Results 41 to 50 of about 768,175 (328)

On Further Refinements of Numerical Radius Inequalities

Axioms, 2023
This paper introduces several generalized extensions of some recent numerical radius inequalities of Hilbert space operators. More preciously, these inequalities refine the recent inequalities that were proved in literature.
Ayman Hazaymeh, Ahmad Qazza, Raed Hatamleh, Mohammad W. Alomari, Rania Saadeh   +4 more
doaj   +1 more source

A note on convexity of sections of quaternionic numerical range

, 2018
The quaternionic numerical range of matrices over the ring of quaternions is not necessarily convex. We prove Toeplitz-Hausdorff like theorem, that is, for any given quaternionic matrix every section of its quaternionic numerical range is convex.
Kumar, P. Santhosh
core   +1 more source

The influence of temperature dynamics and dynamic finite ion Larmor radius effects on seeded high amplitude plasma blobs [PDF]

, 2016
Thermal effects on the perpendicular convection of seeded pressure blobs in the scrape-off layer of magnetised fusion plasmas are investigated. Our numerical study is based on a four field full-F gyrofluid model, which entails the consistent description ...
Held, M., Kendl, A., Madsen, J., Wiesenberger, M.   +3 more
core   +2 more sources

Improved Bounds for the Euclidean Numerical Radius of Operator Pairs in Hilbert Spaces

Mathematics
This paper presents new lower and upper bounds for the Euclidean numerical radius of operator pairs in Hilbert spaces, demonstrating improvements over recent results by other authors.
Najla Altwaijry, Silvestru Sever Dragomir, Kais Feki   +2 more
doaj   +1 more source

Inequalities for operator space numerical radius of $2\times 2$ block matrices

, 2015
In this paper, we study the relationship between operator space norm and operator space numerical radius on the matrix space $\mathcal{M}_n(X)$, when $X$ is a numerical radius operator space. Moreover, we establish several inequalities for operator space
Moslehian, Mohammad Sal, Sattari, Mostafa   +1 more
core   +1 more source

Sharpening some classical numerical radius inequalities [PDF]

Operators and Matrices, 2018
New upper and lower bounds for the numerical radii of Hilbert space operators are given. Among our results, we prove that if $A\in \mathcal{B} \left( \mathcal{H}\right) $ is a hyponormal operator, then for all non-negative non-decreasing operator convex $f$ on $ [0,\infty ),$ we have \[f\left( \left( A \right) \right)\le \frac{1}{2}\left\| f\left ...
Omidvar, Mohsen Erfanian, Moradi, Hamid Reza, Shebrawi, Khalid   +2 more
openaire   +3 more sources

On Some Sufficiency-Type Stability and Linear State-Feedback Stabilization Conditions for a Class of Multirate Discrete-Time Systems

Mathematics, 2018
This paper presents and discusses the stability of a discrete multirate sampling system whose sets of sampling rates (or sampling periods) are the integer multiple of those operating on all the preceding substates.
M. De la Sen
doaj   +1 more source

Numerical range for random matrices

, 2014
We analyze the numerical range of high-dimensional random matrices, obtaining limit results and corresponding quantitative estimates in the non-limit case. For a large class of random matrices their numerical range is shown to converge to a disc.
Collins, Benoît, Gawron, Piotr, Litvak, Alexander E., Życzkowski, Karol   +3 more
core   +1 more source

Convex numerical radius

Journal of Mathematical Analysis and Applications, 2010
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
openaire   +2 more sources

Time after time – circadian clocks through the lens of oscillator theory

FEBS Letters, EarlyView.
Oscillator theory bridges physics and circadian biology. Damped oscillators require external drivers, while limit cycles emerge from delayed feedback and nonlinearities. Coupling enables tissue‐level coherence, and entrainment aligns internal clocks with environmental cues.
Marta del Olmo, Carolin Ector, Hanspeter Herzel   +2 more
wiley   +1 more source