Results 61 to 70 of about 10,743 (170)

Unitarily invariant norms related to factors

, 2007
42 pages, the introduction is rewritten, minor ...
Fang, Junsheng, Hadwin, Don
openaire   +2 more sources

AI‐Enhanced Signal Detection and Channel Estimation for Beyond 5G and 6G Wireless Networks

Transactions on Emerging Telecommunications Technologies, Volume 36, Issue 12, December 2025.
This paper introduces deep learning‐based methods for channel estimation and signal detection in ma‐MIMO systems, significantly improving performance. FF‐PCNet enhances channel estimation with 40.2% lower error, and LSTM‐DetNet and FF‐DetNet signal detection methods, which achieve superior signal detection with up to 99.993% SER performance and reduced
Muhammad Yunis Daha, Bibin Babu, Rizwan Qureshi, Muhammad Usman Hadi   +3 more
wiley   +1 more source

Vladimirov–Pearson operators on ζ$\zeta$‐regular ultrametric Cantor sets

Mathematische Nachrichten, Volume 298, Issue 12, Page 3779-3790, December 2025.
Abstract A new operator for certain types of ultrametric Cantor sets is constructed using the measure coming from the spectral triple associated with the Cantor set, as well as its zeta function. Under certain mild conditions on that measure, it is shown that it is an integral operator similar to the Vladimirov–Taibleson operator on the p$p$‐adic ...
Patrick Erik Bradley
wiley   +1 more source

An Optimal Preconditioned MINRES Method for Symmetrized Multilevel Block Toeplitz Systems With Applications

Numerical Linear Algebra with Applications, Volume 32, Issue 6, December 2025.
ABSTRACT In this work, we propose a novel preconditioned minimal residual method for a class of real, nonsymmetric multilevel block Toeplitz systems, which generalizes an ideal preconditioner established in [J. Pestana. Preconditioners for symmetrized Toeplitz and multilevel Toeplitz matrices. SIAM Journal on Matrix Analysis and Applications, 40(3):870–
Grigorios Tachyridis, Sean Y. Hon
wiley   +1 more source

Spectral Conditions on the State of a Composite Quantum System Implying its Separability

, 2005
For any unitarily invariant convex function F on the states of a composite quantum system which isolates the trace there is a critical constant C such that F(w) C there are entangled states v with F(v)=D. Upper- and lower bounds on C are given.
Alberti P M, Bhatia R, Bouwmeester D, G A Raggio, Gurvits L, Gurvits L Barnum H, Horn R A, Horn R A, Nielsen M A, Ohya M, Raggio G A, Rungta P   +11 more
core   +1 more source

Graph rigidity for unitarily invariant matrix norms

Journal of Mathematical Analysis and Applications, 2020
A rigidity theory is developed for bar-joint frameworks in linear matrix spaces endowed with a unitarily invariant norm. Analogues of Maxwell's counting criteria are obtained and minimally rigid matrix frameworks are shown to belong to the matroidal class of (k,l)-sparse graphs for suitable k and l.
Kitson, Derek, Levene, Rupert H.
openaire   +2 more sources

Conformal optimization of eigenvalues on surfaces with symmetries

Journal of the London Mathematical Society, Volume 112, Issue 6, December 2025.
Abstract Given a conformal action of a discrete group on a Riemann surface, we study the maximization of Laplace and Steklov eigenvalues within a conformal class, considering metrics invariant under the group action. We establish natural conditions for the existence and regularity of maximizers. Our method simplifies the previously known techniques for
Denis Vinokurov
wiley   +1 more source

Singular value inequalities for generalized anticommutators

Journal of Inequalities and Applications
We shown among other inequalities that if A 1 $A_{1}$ , B 1 $B_{1}$ , X 1 $X_{1}$ , and Y 1 $Y_{1}$ are n × n $n\times n$ complex matrices such that A 1 $A_{1}$ and B 1 $B_{1}$ are positive semidefinite, then s j ( Y 1 A 1 X 1 − X 1 B 1 Y 1 ) ≤ s j ( Z ⊕
Manal Al-Labadi, Raja’a Al-Naimi, Wasim Audeh   +2 more
doaj   +1 more source

Nonextreme de Branges-Rovnyak spaces as models for contractions [PDF]

, 2013
The de Branges--Rovnyak spaces are known to provide an alternate functional model for contractions on a Hilbert space, equivalent to the Sz.-Nagy--Foias model.
Mashreghi, Javad, Timotin, Dan
core  

Boundary representations of locally compact hyperbolic groups

Proceedings of the London Mathematical Society, Volume 131, Issue 6, December 2025.
Abstract We develop the theory of Patterson–Sullivan measures for locally compact hyperbolic groups. This theory associates to certain left‐invariant metrics on the group measures on its boundary. Next, we establish irreducibility of the resulting (unitary) Koopman representations for second countable, nonelementary, unimodular locally compact ...
Michael Glasner
wiley   +1 more source