Results 11 to 20 of about 2,915 (59)
The Debiased Spatial Whittle likelihood. [PDF]
J R Stat Soc Series B Stat Methodol, 2022 Abstract We provide a computationally and statistically efficient method for estimating the parameters of a stochastic covariance model observed on a regular spatial grid in any number of dimensions. Our proposed method, which we call the Debiased Spatial Whittle likelihood, makes important corrections to the well‐known Whittle likelihood to account ...
Guillaumin AP +3 more
europepmc +2 more sources
Posterior consistency for the spectral density of non‐Gaussian stationary time series
Scandinavian Journal of Statistics, Volume 50, Issue 3, Page 1152-1182, September 2023., 2023 Abstract Various nonparametric approaches for Bayesian spectral density estimation of stationary time series have been suggested in the literature, mostly based on the Whittle likelihood approximation. A generalization of this approximation involving a nonparametric correction of a parametric likelihood has been proposed in the literature with a proof ...
Yifu Tang +3 more
wiley +1 more source
Beltrami fields and knotted vortex structures in incompressible fluid flows
Bulletin of the London Mathematical Society, Volume 55, Issue 3, Page 1059-1103, June 2023., 2023 Abstract This paper gives a survey on recent results about the existence of knotted vortex structures in incompressible fluids. This includes the proof of Lord Kelvin's conjecture on the existence of knotted vortex tubes in steady Euler flows and a new probabilistic approach to address Arnold's speculation that typical Beltrami fields should exhibit ...
Alberto Enciso, Daniel Peralta‐Salas
wiley +1 more source
International Journal for Numerical Methods in Engineering, Volume 124, Issue 9, Page 1933-1964, 15 May 2023., 2023 Summary This article introduces a robust and affordable method to compute nullspace and generalized inverse of finite element operators involved in dual domain decomposition methods. The methodology relies on the operator partial factorization and on the analysis of a well chosen Schur complement.
Christophe Bovet
wiley +1 more source
Entropy rigidity for cusped Hitchin representations
Journal of Topology, Volume 19, Issue 1, March 2026.Abstract We establish an entropy rigidity theorem for Hitchin representations of geometrically finite Fuchsian groups which generalizes a theorem of Potrie and Sambarino for Hitchin representations of closed surface groups. In the process, we introduce the class of (1,1,2)‐hypertransverse groups and show for such a group that the Hausdorff dimension of
Richard Canary +2 more
wiley +1 more source
Dissipative energy functionals of passive linear time‐varying systems
ZAMM - Journal of Applied Mathematics and Mechanics / Zeitschrift für Angewandte Mathematik und Mechanik, Volume 106, Issue 2, February 2026.Abstract The concept of dissipativity plays a crucial role in the analysis of control systems. Dissipative energy functionals, also known as Hamiltonians, storage functions, or Lyapunov functions, depending on the setting, are extremely valuable to analyze and control the behavior of dynamical systems, but in general circumstances they are very ...
Riccardo Morandin, Dorothea Hinsen
wiley +1 more source
Topological chiral‐gain in a Berry dipole material
Nanophotonics, Volume 14, Issue 23, Page 3991-4003, 02 November 2025.Abstract Recent studies have shown that low‐symmetry conductors under static electric bias offer a pathway to realize chiral gain, where the non‐Hermitian optical response of the material is controlled by the spin angular momentum of the wave. In this work, we uncover the topological nature of chiral gain and demonstrate how a static electric bias ...
Filipa R. Prudêncio +1 more
wiley +1 more source
From Single to Multi‐Material 3D Printing of Glass‐Ceramics for Micro‐Optics
Small Methods, Volume 9, Issue 8, August 20, 2025.This article explores advancements in two‐photon lithography (TPL) for fabricating high‐refractive‐index micro‐optics. It examines single and multi‐material 3D architectures in glass and ceramics (GLACEs), highlighting photoresin customization, critical fabrication conditions, and cross‐scale structural and optical characterization.
Joel Arriaga‐Dávila +10 more
wiley +1 more source
Foundations of Ghost Stability
Fortschritte der Physik, Volume 73, Issue 4, April 2025.Abstract The authors present a new method to analytically prove global stability in ghost‐ridden dynamical systems. The proposal encompasses all prior results and consequentially extends them. In particular, it is shown that stability can follow from a conserved quantity that is unbounded from below, contrary to expectation.
Verónica Errasti Díez +2 more
wiley +1 more source
Second kind functionals for the Laguerre-Hahn affine class on the unit circle [PDF]
, 2003 16 pages, no figures.-- MSC1991 codes: 33C47, 42C05.MR#: MR2032331 (2004j:33013)Zbl#: Zbl 1036.42024The aim of this paper is the study of some transformations in the Laguerre-Hahn affine class that do not preserve the class. Under very general conditions,
Cachafeiro, Alicia +2 more
core +3 more sources