Results 51 to 60 of about 49,230 (203)

On linear operators with an invariant subspace of functions

open access: yes, 2004
6 pages, LaTeX, discussion extended, reference ...
openaire   +2 more sources

Cardiac MR Fingerprinting at 0.55T Using a Deep Image Prior for Joint T1, T2, and M0 Mapping

open access: yesJournal of Magnetic Resonance Imaging, EarlyView.
ABSTRACT Background 0.55T systems offer unique advantages and may support expanded access to cardiac MRI. Purpose To assess the feasibility of 0.55T cardiac MR Fingerprinting (MRF), leveraging a deep image prior reconstruction to mitigate noise. Study Type Phantom and prospective in vivo assessment.
Zhongnan Liu   +9 more
wiley   +1 more source

Characterization of invariant subspaces for a nilpotent linear operator that admit complementary invariant subspaces

open access: yesThe Electronic Journal of Linear Algebra
The aim of this work is to solve the problem of determining the necessary and sufficient conditions for a vector subspace invariant by a nilpotent endomorphism to admit a complementary invariant subspace for the same linear operator. As applications, we offer results about Jordan bases associated with nilpotent linear maps and reflexive generalized ...
openaire   +3 more sources

Frozen Differential Scattering in Reconfigurable Complex Media

open access: yesLaser &Photonics Reviews, EarlyView.
A localized perturbation universally results in a rank‐one update of the scattering matrix of any complex medium. The resulting differential output wavefront is “frozen”: its spatial pattern is fixed (agnostic to the input wavefront). Experiments with a programmable‐metasurface‐parametrized wireless link validate frozen differential scattering and ...
Philipp del Hougne
wiley   +1 more source

Optical Skyrmions with Tunable or Reconfigurable Topology Using Spin‐Decoupled Metaoptics

open access: yesLaser &Photonics Reviews, EarlyView.
The work introduces advanced optical elements capable of generating and dynamically reconfiguring complex light patterns known as optical skyrmions. By precisely shaping light polarization at the nanoscale, a single engineered metasurface can generate and manipulate robust and tunable polarization textures in an efficient and scalable way.
Andrea Vogliardi   +5 more
wiley   +1 more source

Approximation of Dirac operators with δ‐shell potentials in the norm resolvent sense, II: Quantitative results

open access: yesMathematische Nachrichten, EarlyView.
Abstract This paper is devoted to the approximation of two‐ and three‐dimensional Dirac operators HV∼δΣ$H_{\widetilde{V} \delta _\Sigma }$ with combinations of electrostatic and Lorentz scalar δ$\delta$‐shell interactions in the norm resolvent sense. Relying on results from Behrndt, Holzmann, and Stelzer‐Landauer [Math. Nachr.
Jussi Behrndt   +2 more
wiley   +1 more source

Equivalences of Nonlinear Higher Order Fractional Differential Equations With Integral Equations

open access: yesMathematical Methods in the Applied Sciences, Volume 48, Issue 6, Page 6930-6942, April 2025.
ABSTRACT Equivalences of initial value problems (IVPs) of both nonlinear higher order (Riemann–Liouville type) fractional differential equations (FDEs) and Caputo FDEs with the corresponding integral equations are studied in this paper. It is proved that the nonlinearities in the FDEs can be L1$$ {L}^1 $$‐Carathéodory with suitable conditions.
Kunquan Lan
wiley   +1 more source

The number of invariant subspaces under a linear operator on finite vector spaces

open access: yesAdvances in Mathematics of Communications, 2011
Let $V$ be an $n$-dimensional vector space over the finite field $\mathbb F$q and $T$ a linear operator on $V$. For each $k\in\{1,\ldots,n\}$ we determine the number of $k$-dimensional $T$-invariant subspaces of $V$. Finally, this method is applied for the enumeration of all monomially nonisometric linear $(n,k)$-codes over $\mathbb F$q.
openaire   +1 more source

Normalizers of Operator Algebras and Reflexivity

open access: yes, 2002
The set of normalizers between von Neumann (or, more generally, reflexive) algebras A and B, (that is, the set of all operators x such that xAx* is a subset of B and x*Bx is a subset of A) possesses `local linear structure': it is a union of reflexive ...
Katavolos, A., Todorov, I. G.
core  

Interaction of Dirac δ$$ \delta $$‐Waves in the Inviscid Levine and Sleeman Chemotaxis Model

open access: yesMathematical Methods in the Applied Sciences, EarlyView.
ABSTRACT This article investigates interactions of δ$$ \delta $$‐shock waves in the inviscid Levine and Sleeman chemotaxis model ut−λ(uv)x=0$$ {u}_t-\lambda {(uv)}_x=0 $$, vt−ux=0$$ {v}_t-{u}_x=0 $$. The analysis employs a distributional product and a solution concept that extends the classical solution concept.
Adelino Paiva
wiley   +1 more source

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