Results 31 to 40 of about 160 (154)

Observability Inequalities for Transport Equations through Carleman Estimates [PDF]

open access: yes, 2019
We consider the transport equation $\ppp_t u(x,t) + H(t)\cdot \nabla u(x,t) = 0$ in $\OOO\times(0,T),$ where $T>0$ and $\OOO\subset \R^d $ is a bounded domain with smooth boundary $\ppp\OOO$. First, we prove a Carleman estimate for solutions of finite energy with piecewise continuous weight functions. Then, under a further condition which guarantees
Piermarco Cannarsa   +2 more
openaire   +4 more sources

A theorem concerning Fourier transforms: A survey

open access: yesJournal of the London Mathematical Society, Volume 113, Issue 1, January 2026.
Abstract In this note, we highlight the impact of the paper G. H. Hardy, A theorem concerning Fourier transforms, J. Lond. Math. Soc. (1) 8 (1933), 227–231 in the community of harmonic analysis in the last 90 years, reviewing, on one hand, the direct generalizations of the main results and, on the other hand, the different connections to related areas ...
Aingeru Fernández‐Bertolin, Luis Vega
wiley   +1 more source

Phase‐Lag Integro‐Partial Differential Equation: Local and Nonlocal Solutions

open access: yesAdvances in Mathematical Physics, Volume 2026, Issue 1, 2026.
Nonlocal information, such as material deformation, genetic genes, or the history of the disease, are essential as they provide us with additional details that increase the numerical solution’s accuracy. With the help of the phase delay, we may also predict the future of the phenomena we are researching.
Sameeha Ali Raad, Ivan Giorgio
wiley   +1 more source

Carleman Estimates with a Second Large Parameter

open access: yesJournal of Mathematical Analysis and Applications, 2000
Unique continuation of solutions to linear partial differential equations is of importance in many branches of applied mathematics, in particular, in control theory and inverse problems. The Carleman estimates are an important tool for proving the unique continuation for linear operators with non-analytic coefficients.
openaire   +1 more source

Identification of random coefficient latent utility models

open access: yesQuantitative Economics, Volume 16, Issue 4, Page 1223-1265, November 2025.
This paper provides nonparametric identification results for random coefficient distributions in perturbed utility models. We cover discrete choice and models of multiple purchases. We establish identification using variation in mean quantities. The results apply even when an analyst observes only aggregate demands but not whether goods are chosen ...
Roy Allen, John Rehbeck
wiley   +1 more source

Null controllability of a coupled system of degenerate parabolic equations with lower order terms

open access: yesElectronic Journal of Differential Equations, 2019
This article concerns the null controllability of a control system governed by coupled degenerate parabolic equations with lower order terms. For these equations, the convection terms cannot be controlled by the diffusion terms.
Jianing Xu, Qian Zhou, Yuanyuan Nie
doaj  

Integrating the Probe and Singular Sources Methods: II. the Stokes System

open access: yesMathematical Methods in the Applied Sciences, Volume 48, Issue 10, Page 10406-10426, 15 July 2025.
ABSTRACT In this paper, an integrated theory of the probe and singular sources methods for an inverse obstacle problem governed by the Stokes system in a bounded domain is developed. The main results consist of the probe method for the Stokes system, the singular sources method by using the notion of the probe method, and the completely integrated ...
Masaru Ikehata
wiley   +1 more source

Carleman estimates for the Euler-Bernoulli plate operator

open access: yesElectronic Journal of Differential Equations, 2000
We present some a-priori estimates of Carleman type for the Euler-Bernoulli plate operator. As an application, we consider a problem of boundary observability for the Euler-Bernoulli plate coupled with the heat equation.
Paolo Albano
doaj  

Properties of the Support of Solutions of a Class of 2-Dimensional Nonlinear Evolution Equations.

open access: yesRevista Integración, 2021
In this work we consider equations of the form ∂tu + P(D)u + u^{t}∂xu = 0, where P(D) is a two-dimensional differential operator, and l ∈ N. We prove that if u is a sufficiently smooth solution of the equation, such that supp u(0), supp u(T) ⊂ [−B,
Eddye Bustamante, José Jiménez Urrea
doaj  

OPTIMAL CONTROL FOR A CONTROLLED ILL-POSED WAVE EQUATION WITHOUT REQUIRING THE SLATER HYPOTHESIS

open access: yesUral Mathematical Journal, 2020
In this paper, we investigate the problem of optimal control for an ill-posed wave equation without using the extra hypothesis of Slater i.e. the set of admissible controls has a non-empty interior. Firstly, by a controllability approach, we make the ill-
Abdelhak Hafdallah
doaj   +1 more source

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