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Fixed-time stable dynamical systems are capable of achieving exact convergence to an equilibrium point within a fixed time that is independent of the initial conditions of the system. This property makes them highly appealing for designing…

Systems and Control · Electrical Eng. & Systems 2025-10-01 Michael Tang , Miroslav Krstic , Jorge Poveda

We study dimension theory for dissipative dynamical systems, proving a conditional variational principle for the quotients of Birkhoff averages restricted to the recurrent part of the system. On the other hand, we show that when the whole…

Dynamical Systems · Mathematics 2018-09-18 Godofredo Iommi , Thomas Jordan , Mike Todd

For any fixed irrational frequency and trigonometric-polynomial potential, we show that every type I energy with positive Lyapunov exponent that satisfies the gap-labelling condition is a boundary of an open spectral gap. As a corollary,…

Dynamical Systems · Mathematics 2026-04-09 Xianzhe Li , Disheng Xu , Qi Zhou

We obtained estimates for first eigenvalues of the Dirichlet boundary value problem for elliptic operators in divergence form (i.e. for the principal frequency of non-homogeneous membranes) in bounded domains $\Omega \subset \mathbb C$…

Analysis of PDEs · Mathematics 2023-01-18 Vladimir Gol'dshtein , Valery Pchelintsev

We study the spectral theory and inverse problem on asymptotically hyperbolic manifolds. The main subjects are as follows: (1)Location of the essential spectrum. (2)Absence of eigenvalues embedded in the continuous spectrum. (3)Limiting…

Spectral Theory · Mathematics 2012-08-23 Hiroshi Isozaki , Yaroslav Kurylev

The First and Second Representation Theorem for sign-indefinite quadratic forms are extended. We include new cases of unbounded forms associated with operators that do not necessarily have a spectral gap around zero. The kernel of the…

Functional Analysis · Mathematics 2015-09-25 Stephan Schmitz

The aim of this article is to show how certain parabolic theorems follow from their elliptic counterparts. This technique is demonstrated through new proofs of five important theorems in parabolic unique continuation and the regularity…

Analysis of PDEs · Mathematics 2017-10-18 Blair Davey

Based on the covariant underdamped and overdamped Langevin equations with Stratonovich coupling to multiplicative noises and the associated Fokker-Planck equations on Riemannian manifold, we present the first law of stochastic…

Statistical Mechanics · Physics 2024-04-02 Yifan Cai , Tao Wang , Liu Zhao

The paper discusses the relationships between electrical and affine differential geometry quantities, establishing a link between frequency and time derivatives of voltage, through the utilization of affine geometric invariants. Based on…

Differential Geometry · Mathematics 2024-09-26 Ali Alshawabkeh , Georgios Tzounas , Angel Molina-Garcia , Federico Milano

The invariance principle, through which the steady-state behavior of nonlinear systems was introduced by Isidori and Byrnes, is leveraged in this article to bring forth a unifying characterization of the frequency response of nonlinear…

Systems and Control · Electrical Eng. & Systems 2026-04-16 Alessio Moreschini , Matteo Scandella

This paper is devoted to the study of $L_p$ Lyapunov-type inequalities for linear systems of equations with Neumann boundary conditions and for any constant $p \geq 1$. We consider ordinary and elliptic problems. The results obtained in the…

Analysis of PDEs · Mathematics 2009-06-08 Antonio Canada , Salvador Villegas

We study the transversal wave equation on a compact Riemannian foliated manifold. As applications, we get an Egorov's type theorem for transversally elliptic operators, state a relationship between the singularities of the Fourier transform…

dg-ga · Mathematics 2008-02-03 Yuri A. Kordyukov

We develop the regularity theory for solutions to space-time nonlocal equations driven by fractional powers of the heat operator $$(\partial_t-\Delta)^su(t,x)=f(t,x),\quad\hbox{for}~0<s<1.$$ This nonlocal equation of order $s$ in time and…

Analysis of PDEs · Mathematics 2017-04-14 P. R. Stinga , J. L. Torrea

We examine the band-gap structure of the spectrum of the Neumann problem for the Laplace operator in a strip with periodic dense transversal perforation by identical holes of a small diameter $\varepsilon>0$. The periodicity cell itself…

Analysis of PDEs · Mathematics 2023-02-14 Delfina Gómez , Sergei A. Nazarov , Rafael Orive-Illera , Maria-Eugenia Pérez-Martínez

In this study, the theorem on necessary and sufficient conditions for the solvability of inverse problem for Sturm-Liouville operator with discontinuous coefficient is proved and the algorithm of reconstruction of potential from spectral…

Spectral Theory · Mathematics 2016-04-21 Döne Karahan , Khanlar. R. Mamedov

This paper addresses the stabilization issue for fractional order switching systems. Common Lyapunov method is generalized for fractional order systems and frequency domain stability equivalent to this method is proposed to prove the…

Adaptation and Self-Organizing Systems · Physics 2012-05-29 S. Hassan HosseinNia , Inés Tejado , Blas M. Vinagre

We numerically study in the one-dimensional case the validity of the functional calculated by Graham and coworkers as a Lyapunov potential for the Complex Ginzburg-Landau equation. In non-chaotic regions of parameter space the functional…

Condensed Matter · Physics 2015-06-25 R. Montagne , E. Hernandez-Garcia , M. San Miguel

In this paper,we present a rigorous demonstration and discussion of the quantum adiabatic theorem for systems having a non degenerate continuous spectrum. A new strategy is initiated by defining a kind of gap, "a virtual gap", for the…

Quantum Physics · Physics 2008-04-28 M. Maamache , Y. Saadi

We consider the Schr\"odinger operator on the real line with a 2x2 matrix valued 1-periodic potential. The spectrum of this operator is absolutely continuous and consists of intervals separated by gaps. We define a Lyapunov function which…

Spectral Theory · Mathematics 2007-05-23 Andrei Badanin , Jochen Brüning , Evgeny Korotyaev

This paper is related to an inverse problem for a class of Dirac operators with discontinuous coefficient and eigenvalue parameter contained in boundary conditions. The asymptotic formula of eigenvalues of this problem is examined. The…

Spectral Theory · Mathematics 2015-10-13 Khanlar R. Mamedov , Ozge Akcay