Results 21 to 30 of about 357 (99)

Band‐Pass Filtering With High‐Dimensional Time Series. A Synthetic Indicator of the Medium‐to‐Long Run Component of Growth

Journal of Time Series Analysis, EarlyView.
ABSTRACT The paper deals with the construction of a synthetic indicator of economic growth, obtained by projecting a quarterly measure of aggregate economic activity, namely gross domestic product (GDP), into the space spanned by a finite number of smooth principal components, representative of the medium‐to‐long‐run component of economic growth of a ...
Alessandro Giovannelli, Marco Lippi, Tommaso Proietti   +2 more
wiley   +1 more source

Riemann-Hilbert problems, Toeplitz operators and ergosurfaces

Journal of High Energy Physics
The Riemann-Hilbert approach, in conjunction with the canonical Wiener-Hopf factorisation of certain matrix functions called monodromy matrices, enables one to obtain explicit solutions to the non-linear field equations of some gravitational theories ...
M. Cristina Câmara, Gabriel Lopes Cardoso   +1 more
doaj   +1 more source

Properties of Matrix Orthogonal Polynomials via their Riemann-Hilbert Characterization

Symmetry, Integrability and Geometry: Methods and Applications, 2011
We give a Riemann-Hilbert approach to the theory of matrix orthogonal polynomials. We will focus on the algebraic aspects of the problem, obtaining difference and differential relations satisfied by the corresponding orthogonal polynomials.
F. Alberto Grünbaum, Manuel D. de la Iglesia, Andrei Martínez-Finkelshtein   +2 more
doaj   +1 more source

Isoperimetric inequalities on slabs with applications to cubes and Gaussian slabs

Communications on Pure and Applied Mathematics, Volume 79, Issue 4, Page 1012-1072, April 2026.
Abstract We study isoperimetric inequalities on “slabs”, namely weighted Riemannian manifolds obtained as the product of the uniform measure on a finite length interval with a codimension‐one base. As our two main applications, we consider the case when the base is the flat torus R2/2Z2$\mathbb {R}^2 / 2 \mathbb {Z}^2$ and the standard Gaussian measure
Emanuel Milman
wiley   +1 more source

The Solvability and Explicit Solutions of Singular Integral–Differential Equations with Reflection

Abstract and Applied Analysis
This article deals with a classes of singular integral–differential equations with convolution kernel and reflection. By means of the theory of boundary value problems of analytic functions and the theory of Fourier analysis, such equations can be ...
A. S. Nagdy, KH. M. Hashem, H. E. H. Ebrahim   +2 more
doaj   +1 more source

A note on the Steinitz lemma

Mathematika, Volume 72, Issue 2, April 2026.
Abstract We establish the connection between the Steinitz problem for ordering vector families in arbitrary norms and its variant for not necessarily zero‐sum families consisting of “nearly unit” vectors.
Gergely Ambrus, Rainie Heck
wiley   +1 more source

The elliptic sinh-Gordon equation in a semi-strip

Advances in Nonlinear Analysis, 2017
We study the elliptic sinh-Gordon equation posed in a semi-strip by applying the so-called Fokas method, a generalization of the inverse scattering transform for boundary value problems.
Hwang Guenbo
doaj   +1 more source

A Re‐Examination of Foundational Elements of Cosmology

Fortschritte der Physik, Volume 74, Issue 3, March 2026.
ABSTRACT This paper undertakes a conceptual re‐examination of several foundational elements of cosmology through the lens of spacetime symmetries. A new derivation of the Friedmann–Lemaître–Robertson–Walker metric is obtained by a careful conceptual examination of rotations and translations on generic manifolds, followed by solving the rotational and ...
Lavinia Heisenberg
wiley   +1 more source

Hyperderivatives of the deformation series associated with arithmetic gamma values and characteristic p$p$ multiple zeta values

Journal of the London Mathematical Society, Volume 113, Issue 3, March 2026.
Abstract Number theory for positive characteristic contains analogues of the special values that were introduced by Carlitz; these include the Carlitz gamma values and Carlitz zeta values. These values were further developed to the arithmetic gamma values and multiple zeta values by Goss and Thakur, respectively.
Ryotaro Harada, Daichi Matsuzuki
wiley   +1 more source

On a new approach to the study of plane boundary-value problems

Доповiдi Нацiональної академiї наук України
We give a short description of our recent results obtained by a new approach to the boundary-value problems, such as the Dirichlet, Hilbert, Neumann, Poincaré and Riemann problems, for the Beltrami equations and for analogs of the Laplace equation in ...
V.Ya. Gutlyanskiĭ, V.I. Ryazanov, A.S. Yefimushkin   +2 more
doaj   +1 more source