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In general, geometries of Petrov type II do not admit symmetries in terms of Killing vectors or spinors. We introduce a weaker form of Killing equations which do admit solutions. In particular, there is an analog of the Penrose-Walker…

General Relativity and Quantum Cosmology · Physics 2021-07-07 Steffen Aksteiner , Lars Andersson , Bernardo Araneda , Bernard Whiting

We study the number of exponentially small singular values of the semiclassical $\overline{\partial}$ operator on exponentially weighted $L^2$ spaces on the two-dimensional torus. Accurate upper and lower bounds on the number of such…

Spectral Theory · Mathematics 2025-05-28 Michael Hitrik , Johannes Sjöstrand , Martin Vogel

For indices p and q, 1 < p <= q < infini and a linear operator L satisfying some weak-type boundedness conditions on suitable function spaces, we give in the Dunkl setting sufficient conditions on nonnegative pairs of weight functions to…

Analysis of PDEs · Mathematics 2013-11-05 Chokri Abdelkefi , Mongi Rachdi

We show that two Weyl group actions on the Springer sheaf with arbitrary coefficients, one defined by Fourier transform and one by restriction, agree up to a twist by the sign character. This generalizes a familiar result from the setting…

Representation Theory · Mathematics 2014-06-18 Pramod N. Achar , Anthony Henderson , Daniel Juteau , Simon Riche

We investigate the local structure of four-dimensional Lorentzian quasi-Einstein manifolds under conditions on the Weyl tensor. We show that if the Weyl tensor is harmonic and the potential function preserves this harmonicity then, in the…

Differential Geometry · Mathematics 2020-01-08 Miguel Brozos-Vázquez , Eduardo García-Río , Xabier Valle-Regueiro

In this paper, the authors propose a new framework under which a theory of generalized Besov-type and Triebel-Lizorkin-type function spaces is developed. Many function spaces appearing in harmonic analysis fall under the scope of this new…

Classical Analysis and ODEs · Mathematics 2014-01-30 Yiyu Liang , Dachun Yang , Wen Yuan , Yoshihiro Sawano , Tino Ullrich

Covering ill-posed problems with compact and non-compact operators regarding the degree of ill-posedness is a never ending story written by many authors in the inverse problems literature. This paper tries to add a new narrative and some…

Numerical Analysis · Mathematics 2024-11-27 Frank Werner , Bernd Hofmann

The classical unified theory of Weyl is revisited. The possibility of stable extended electron model in the Einstein-Weyl space is suggested.

General Relativity and Quantum Cosmology · Physics 2007-05-23 S. C. Tiwari

Some preliminaries and basic facts regarding unbounded Wiener-Hopf operators (WH) are provided. WH with rational symbols are studied in detail showing that they are densely defined closed and have finite dimensional kernels and deficiency…

Functional Analysis · Mathematics 2021-05-18 Domenico P. L. Castrigiano

We derive point-wise and integral rigidity/gap results for a closed manifold with harmonic Weyl curvature in any dimension. In particular, there is a generalization of Tachibana's theorem for non-negative curvature operator. The key…

Differential Geometry · Mathematics 2017-11-15 Hung Tran

Let $V$ be a linear representation of a connected complex reductive group $G$. Given a choice of character $\theta$ of $G$, Geometric Invariant Theory defines a locus $V^{ss}_\theta(G) \subseteq V$ of semistable points. We give necessary,…

Representation Theory · Mathematics 2025-10-07 Riku Kurama , Ruoxi Li , Henry Talbott , Rachel Webb

We prove that the kernel of the action the group algebra of the Weyl group acting on tensor space (via restriction of the action from the general linear group) is a cell ideal with respect to the alternating Murphy basis. This provides an…

Representation Theory · Mathematics 2021-07-07 Chris Bowman , Stephen Doty , Stuart Martin

This paper has aim to characterize Fredholmness and Weylness of upper triangular operator matrices having arbitrary dimension n. We present various characterization results in the setting of infinite dimensional Hilbert spaces, thus…

Functional Analysis · Mathematics 2025-08-27 Nikola Sarajlija

The description of all correct restrictions of the maximal operator are considered in a Hilbert space. A class of correct restrictions are obtained for which a similar transformation has the domain of the fixed correct restriction. The…

Spectral Theory · Mathematics 2021-03-11 B. N. Biyarov

We consider the Riemann-Hilbert factorization approach to the construction of Weyl metrics in four space-time dimensions. We present, for the first time, a rigorous proof of the remarkable fact that the canonical Wiener-Hopf factorization…

Mathematical Physics · Physics 2020-06-02 P. Aniceto , M. C. Câmara , G. L. Cardoso , M. Rosselló

The Wigner-Weyl isomorphism for quantum mechanics on a compact simple Lie group $G$ is developed in detail. Several New features are shown to arise which have no counterparts in the familiar Cartesian case. Notable among these is the notion…

Quantum Physics · Physics 2009-11-10 N. Mukunda , G. Marmo , Alessandro Zampini , S. Chaturvedi , R. Simon

We present a tensor description of Euclidean spaces that emphasizes the use of geometric vectors. We demonstrate the effectiveness of the approach by proving of a number of integral identities with vector integrands.

Differential Geometry · Mathematics 2021-10-14 Pavel Grinfeld

In this paper we derive a differential identity for linearized gravity on the Kerr spacetime and more generally on vacuum spacetimes of Petrov type D. We show that a linear combination of second derivatives of the linearized Weyl tensor can…

General Relativity and Quantum Cosmology · Physics 2019-02-26 Steffen Aksteiner , Lars Andersson , Thomas Bäckdahl

Noticing that really the fermions of the Standard Model are best thought of as Weyl - rather than Dirac - particles (relative to fundamental scales located at some presumably very high energies) it becomes interesting that the experimental…

High Energy Physics - Theory · Physics 2009-09-25 Holger Bech Nielsen , Svend Erik Rugh

We establish a Wiener-type integral condition for first-order Sobolev functions defined on a complete, doubling metric measure space supporting a Poincar\'e inequality. It is stronger than the Lebesgue point property, except for a marginal…

Functional Analysis · Mathematics 2024-08-23 M. Ashraf Bhat , G. Sankara Raju Kosuru