Results 61 to 70 of about 194 (182)

Robust Tests of Forecast Accuracy for Factor‐Augmented Regressions With an Application to the Novel EA‐MD‐QD Dataset

open access: yesJournal of Applied Econometrics, EarlyView.
ABSTRACT We present four novel tests of equal predictive accuracy and encompassing á Pitarakis (2023, 2025) for factor‐augmented regressions. Factors are estimated using cross‐section averages (CAs) of grouped series and our theoretical findings are empirically relevant: asymptotic normality, robustness to an overspecification of the number of factors,
Alessandro Morico, Ovidijus Stauskas
wiley   +1 more source

On the representability of actions of non-associative algebras

open access: yes
It is well known that, in the semi-abelian category Lie of Lie algebras over a field F, algebra actions are represented by derivations. This means that the category Lie is action representable and the representing object, which is called the actor, is ...
Manuel Mancini
core   +1 more source

Theory of Supercritical Coupling and Generalized Bound States in the Continuum

open access: yesLaser &Photonics Reviews, EarlyView.
We develop a general theory of supercritical coupling and generalized bound states in the continuum (gBICs), revealing how interference between radiative and absorptive channels enables quality factors beyond conventional material‐loss limits. The framework unifies non‐Hermitian mode coupling, causality‐driven reactive interactions, and interference ...
Sergio Balestrieri   +3 more
wiley   +1 more source

Four‐Dimensional pp‐Wave Lie Groups and Harmonic Curvature

open access: yesMathematische Nachrichten, EarlyView.
ABSTRACT We determine all four‐dimensional Lie groups which have harmonic curvature. In parallel, a description of four‐dimensional pp‐wave Lie groups is obtained.
E. García‐Río   +2 more
wiley   +1 more source

Invariants of the action of a Hopf algebra in a free algebra

open access: yes
As álgebras de Hopf generalizam algumas classes bem abrangentes de álgebras como álgebras de grupo e álgebras envolventes universais de álgebras de Lie.
Ogawa, Lucas Seidy
core   +1 more source

Kuga–Satake Construction on Families of K3 Surfaces of Picard Rank 14

open access: yesMathematische Nachrichten, EarlyView.
ABSTRACT The isometry between the type IV6 and the type II4 hermitian symmetric domains suggests a possible relation between suitable moduli spaces of K3 surfaces of Picard rank 14 and of polarized abelian 8‐folds with totally definite quaternion multiplication. We show how this isometry induces a geometrically meaningful map between such moduli spaces
Flora Poon
wiley   +1 more source

Bifurcation instructed design of multistate machines. [PDF]

open access: yesProc Natl Acad Sci U S A, 2023
Yang T   +6 more
europepmc   +1 more source

Extending the hyper‐logistic model to the random setting: New theoretical results with real‐world applications

open access: yesMathematical Methods in the Applied Sciences, EarlyView.
We develop a full randomization of the classical hyper‐logistic growth model by obtaining closed‐form expressions for relevant quantities of interest, such as the first probability density function of its solution, the time until a given fixed population is reached, and the population at the inflection point.
Juan Carlos Cortés   +2 more
wiley   +1 more source

A Geometric Interpretation for the Algebraic Properties of Second‐Order Ordinary Differential Equations

open access: yesMathematical Methods in the Applied Sciences, Volume 48, Issue 6, Page 6912-6917, April 2025.
ABSTRACT Nowadays, a substantial portion of investigations concerning the symmetry analysis of differential equations predominantly adhere to a framework comprising the following key procedures: (i) the derivation of symmetries, (ii) the determination of an optimal system, (iii) the utilization of these symmetries to construct invariants or ...
A. Paliathanasis   +2 more
wiley   +1 more source

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