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Our manuscript aims to analysis the viability and stability of anisotropic stellar objects in the modified symmetric teleparallel gravity. A particular model of this extended theory is considered to formulate explicit field equations which…

General Relativity and Quantum Cosmology · Physics 2024-08-29 M. Zeeshan Gul , M. Sharif , Adeeba Arooj

A stationary rotating surface is a compact surface in Euclidean space whose mean curvature $H$ at each point $x$ satisfies $2H(x)=a r^2+b$, where $r$ is the distance from $x$ to a fixed straight-line $L$, and $a$ and $b$ are constants.…

Differential Geometry · Mathematics 2008-09-24 Rafael López

We analyze the stability of the Einstein static universe by considering homogeneous scalar perturbations in the context of f(R) modified theories of gravity. By considering specific forms of f(R), the stability regions of the solutions are…

General Relativity and Quantum Cosmology · Physics 2012-06-22 Christian G. Boehmer , Lukas Hollenstein , Francisco S. N. Lobo

We provide a constructive method designed in order to control the stability of a given periodic orbit of a general completely integrable system. The method consists of a specific type of perturbation, such that the resulting perturbed…

Dynamical Systems · Mathematics 2015-03-04 Razvan M. Tudoran

We consider a stabilized finite element method based on a spacetime formulation, where the equations are solved on a global (unstructured) spacetime mesh. A unique continuation problem for the wave equation is considered, where data is…

Numerical Analysis · Mathematics 2023-05-10 Erik Burman , Ali Feizmohammadi , Arnaud Munch , Lauri Oksanen

We consider the Rydberg electron in a circularly polarized microwave field, whose dynamics is described by a 2 d.o.f. Hamiltonian, which is a perturbation of size $K>0$ of the standard rotating Kepler problem. In a rotating frame, the…

Dynamical Systems · Mathematics 2024-11-18 Amadeu Delshams , Mercè Ollé , Juan Ramon Pacha , Óscar Rodríguez

Immersion and Invariance is a technique for the design of stabilizing and adaptive controllers and state observers for nonlinear systems. In all these applications the problem considered is the stabilization of equilibrium points. Motivated…

Systems and Control · Computer Science 2019-12-03 Romeo Ortega , Bowen Yi , Jose Guadalupe Romero , Alessandro Astolfi

We derive the equations of motion for relativistic elastic membranes, that is, two-dimensional elastic bodies whose internal energy depends only on their stretching, starting from a variational principle. We show how to obtain conserved…

General Relativity and Quantum Cosmology · Physics 2025-01-03 Paulo Mourão , José Natário , Rodrigo Vicente

In this short note we treat a 1+1-dimensional system of changing type. On different spatial domains the system is of hyperbolic and elliptic type, that is, formally, $\partial_t^2 u_n-\partial_x^2 u_n = \partial_t f$ and $u_n-\partial_x^2…

Analysis of PDEs · Mathematics 2016-04-12 Marcus Waurick

We study the stability of rotating collisionless self-gravitating spherical systems by using high resolution N-body experiments on a Connection Machine CM-5. We added rotation to Ossipkov-Merritt (hereafter OM) anisotropic spherical systems…

Astrophysics · Physics 2009-10-31 J. -M. Alimi , J. Perez , A. Serna

We consider the cubic-quintic nonlinear Schr{\"o}dinger equation in space dimension up to three. The cubic nonlinearity is thereby focusing while the quintic one is defocusing, ensuring global well-posedness of the Cauchy problem in the…

Analysis of PDEs · Mathematics 2023-12-07 Rémi Carles , Christof Sparber

In this note, we solve the Gauss image problem given two Borel measures on the unit sphere, one of which is absolutely continuous with respect to the uniform measure.

Metric Geometry · Mathematics 2023-08-31 Jérôme Bertrand

Solvability of the ubiquitous quantum harmonic oscillator relies on a spectrum generating osp(1|2) superconformal symmetry. We study the problem of constructing all quantum mechanical models with a hidden osp(1|2) symmetry on a given space…

High Energy Physics - Theory · Physics 2017-12-20 R. Bonezzi , O. Corradini , E. Latini , A. Waldron

We construct infinite families of topologically isotopic but smoothly distinct knotted spheres in many simply connected 4-manifolds that become smoothly isotopic after stabilizing by connected summing with $S^2 \times S^2$, and as a…

Geometric Topology · Mathematics 2015-06-12 Dave Auckly , Hee Jung Kim , Paul Melvin , Daniel Ruberman

The classical one-phase Stefan problem describes the temperature distribution in a homogeneous medium undergoing a phase transition, such as ice melting to water. This is accomplished by solving the heat equation on a time-dependent domain…

Analysis of PDEs · Mathematics 2013-10-22 Mahir Hadžić , Steve Shkoller

A recent analysis by one of the authors\cite{Perivolaropoulos:2018cgr} has pointed out that Derrick's theorem can be evaded in curved space. Here we extend that analysis by demonstrating the existence of a static metastable solution in a…

General Relativity and Quantum Cosmology · Physics 2019-03-27 G. Alestas , L. Perivolaropoulos

We solve the rigidity problem for uniform Roe algebras, by showing that two uniformly locally finite metric spaces with isomorphic uniform Roe algebras are bijectively coarsely equivalent.

Operator Algebras · Mathematics 2026-02-03 Alessandro Vignati

This paper introduces the concept of Hyers-Ulam stability for linear relations in normed linear spaces and presents several intriguing results that characterize the Hyers-Ulam stability of closed linear relations in Hilbert spaces.…

Functional Analysis · Mathematics 2025-01-28 Arup Majumdar

We investigate the stability of scalar perturbations around a magnetized stationary compact object in General Relativity. The considered object is one of the simplest exact solutions of Einstein electrovacuum equations corresponding to a…

General Relativity and Quantum Cosmology · Physics 2025-01-16 Eveling C. Ribeiro , L. Formigari , Marcos R. Ribeiro , Elcio Abdalla , Bertha Cuadros-Melgar , C. Molina , Amilcar R. de Queiroz , Alberto Saa

This paper analyzes the stability of the closed Einstein static universe by using linear homogeneous perturbations in the framework of energy-momentum squared gravity. This newly developed proposal resolves the primordial singularity and…

General Relativity and Quantum Cosmology · Physics 2021-08-25 M. Sharif , M. Zeeshan Gul