Results 21 to 30 of about 3,278,971 (302)

A Counterexample in Unique Continuation [PDF]

open access: yesMathematical Research Letters, 2000
The authors prove the theorem: ``There are measurable functions \(u\), \(V\) defined on \(\mathbb{R}^2\), both supported in \(\overline B_1\), where \(B_1\) is the open unit disc, which are smooth in \(B_1\), such that \(u\), \(V\), \(Vu\in L^1(\mathbb{R}^2)\), and such that \(\Delta u-Vu= 0\) in \({\mathcal D}'\),'' thus answering a question of ...
Kenig, Carlos E., Nadirashvili, Nikolai
openaire   +1 more source

Boundary Unique Continuation on $$C^1$$-Dini Domains and the Size of the Singular Set [PDF]

open access: yesArchive for Rational Mechanics and Analysis, 2021
Let $u$ be a harmonic function in a $C^1$-Dini domain $D$ such that $u$ vanishes on a boundary surface ball $\partial D \cap B_{5R}(0)$. We consider an effective version of its singular set (up to boundary) $\mathcal{S}(u):=\{X\in \overline{D}: u(X ...
C. Kenig, Zihui Zhao
semanticscholar   +1 more source

A primal dual mixed finite element method for inverse identification of the diffusion coefficient and its relation to the Kohn-Vogelius penalty method

open access: yesSelecciones Matemáticas, 2023
We revisit the celebrated Kohn-Vogelius penalty method and discuss how to use it for the unique continuation problem where data is given in the bulk of the domain.
Erik Burman
doaj   +1 more source

Unique continuation property and Poincaré inequality for higher order fractional Laplacians with applications in inverse problems [PDF]

open access: yesInverse Problems and Imaging, 2020
We prove a unique continuation property for the fractional Laplacian $(-\Delta)^s$ when $s \in (-n/2,\infty)\setminus \mathbb{Z}$. In addition, we study Poincar\'e-type inequalities for the operator $(-\Delta)^s$ when $s\geq 0$.
Giovanni Covi, Keijo Monkkonen, J. Railo
semanticscholar   +1 more source

Weak damping for the Korteweg-de Vries equation

open access: yesElectronic Journal of Qualitative Theory of Differential Equations, 2021
For more than 20 years, the Korteweg–de Vries equation has been intensively explored from the mathematical point of view. Regarding control theory, when adding an internal force term in this equation, it is well known that the Korteweg–de Vries equation ...
Roberto de A. Capistrano Filho
doaj   +1 more source

Solving ill-posed Helmholtz problems with physics-informed neural networks

open access: yesJournal of Numerical Analysis and Approximation Theory, 2023
We consider the unique continuation (data assimilation) problem for the Helmholtz equation and study its numerical approximation based on physics-informed neural networks (PINNs).
Mihai Nechita
doaj   +1 more source

Higher-order fractional Laplacians: An overview

open access: yesBruno Pini Mathematical Analysis Seminar, 2022
We summarize some of the most recent results regarding the theory of higher-order fractional Laplacians, i.e., the operators obtained by considering (non-integer) powers greater than 1 of the Laplace operator.
Nicola Abatangelo
doaj   +1 more source

On the unique continuation of solutions to non-local non-linear dispersive equations [PDF]

open access: yesCommunications in Partial Differential Equations, 2020
We prove unique continuation properties of solutions to a large class of nonlinear, non-local dispersive equations. The goal is to show that if are two suitable solutions of the equation defined in such that for some non-empty open set for then for any ...
C. Kenig   +3 more
semanticscholar   +1 more source

A Note on Unique Continuation for Schrodinger's Operator [PDF]

open access: yesProceedings of the American Mathematical Society, 1988
In this paper we shall prove a unique continuation theorem for Schrödinger’s operator, i ∂
Kenig, Carlos E., Sogge, Christopher D.
openaire   +2 more sources

Large‐Scale Analyticity and Unique Continuation for Periodic Elliptic Equations [PDF]

open access: yesCommunications on Pure and Applied Mathematics, 2020
We prove that a solution of an elliptic operator with periodic coefficients behaves on large scales like an analytic function in the sense of approximation by polynomials with periodic corrections.
S. Armstrong   +2 more
semanticscholar   +1 more source

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