0000000000148467

AUTHOR

Leo Tzou

0000-0002-7741-440x

showing 7 related works from this author

Partial data inverse problems for Maxwell equations via Carleman estimates

2015

In this article we consider an inverse boundary value problem for the time-harmonic Maxwell equations. We show that the electromagnetic material parameters are determined by boundary measurements where part of the boundary data is measured on a possibly very small set. This is an extension of earlier scalar results of Bukhgeim-Uhlmann and Kenig-Sj\"ostrand-Uhlmann to the Maxwell system. The main contribution is to show that the Carleman estimate approach to scalar partial data inverse problems introduced in those works can be carried over to the Maxwell system.

Inverse problemsELECTRODYNAMICSINFORMATIONadmissible manifoldsWEIGHTSMathematics::Analysis of PDEsBoundary (topology)InverseBOUNDARY-VALUE PROBLEMCALDERON PROBLEMpartial data01 natural sciencesMATERIAL PARAMETERSinversio-ongelmatsymbols.namesakeMathematics - Analysis of PDEsFOS: Mathematics35R30 35Q61111 MathematicsMaxwellin yhtälötBoundary value problemUniqueness0101 mathematicsPartial dataMathematical PhysicsMathematicsAdmissible manifoldsApplied Mathematicsta111010102 general mathematicsMathematical analysisScalar (physics)Inverse problemCarleman estimatesSmall set010101 applied mathematicsUNIQUENESSMaxwell's equationsMaxwell equationsLOCAL DATAsymbolsAnalysisAnalysis of PDEs (math.AP)
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Partial data inverse problems for the Hodge Laplacian

2017

We prove uniqueness results for a Calderon type inverse problem for the Hodge Laplacian acting on graded forms on certain manifolds in three dimensions. In particular, we show that partial measurements of the relative-to-absolute or absolute-to-relative boundary value maps uniquely determine a zeroth order potential. The method is based on Carleman estimates for the Hodge Laplacian with relative or absolute boundary conditions, and on the construction of complex geometric optics solutions which reduce the Calderon type problem to a tensor tomography problem for 2-tensors. The arguments in this paper allow to establish partial data results for elliptic systems that generalize the scalar resu…

Mathematics - Differential GeometryPure mathematicsadmissible manifoldsType (model theory)partial data01 natural sciences58J32inversio-ongelmatMathematics - Analysis of PDEsFOS: MathematicsBoundary value problemUniquenessTensor0101 mathematicsMathematicsNumerical Analysisabsolute and relative boundary conditionsGeometrical opticsinverse problemsApplied Mathematicsta111010102 general mathematicsScalar (physics)Inverse problemCarleman estimates010101 applied mathematics35R30Differential Geometry (math.DG)Hodge LaplacianLaplace operatorAnalysisAnalysis of PDEs (math.AP)Analysis & PDE
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Stability estimates for the magnetic Schrödinger operator with partial measurements

2022

In this article, we study stability estimates when recovering magnetic fields and electric potentials in a simply connected open subset in Rn with n≥3, from measurements on open subsets of its boundary. This inverse problem is associated with a magnetic Schrödinger operator. Our estimates are quantitative versions of the uniqueness results obtained by D. Dos Santos Ferreira, C.E. Kenig, J. Sjöstrand and G. Uhlmann in [13]. The moduli of continuity are of logarithmic type. peerReviewed

osittaisdifferentiaaliyhtälötApplied MathematicsmagneettikentätAnalysisinversio-ongelmat
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Inverse problems and invisibility cloaking for FEM models and resistor networks

2013

In this paper we consider inverse problems for resistor networks and for models obtained via the finite element method (FEM) for the conductivity equation. These correspond to discrete versions of the inverse conductivity problem of Calderón. We characterize FEM models corresponding to a given triangulation of the domain that are equivalent to certain resistor networks, and apply the results to study nonuniqueness of the discrete inverse problem. It turns out that the degree of nonuniqueness for the discrete problem is larger than the one for the partial differential equation. We also study invisibility cloaking for FEM models, and show how an arbitrary body can be surrounded with a layer …

finite element methodBoundary (topology)CloakingInverse35R30 65N30 05C5001 natural sciencesDomain (mathematical analysis)inversio-ongelmatMathematics - Analysis of PDEsFOS: MathematicsMathematics - Numerical Analysis0101 mathematicsMathematicsPartial differential equationinverse problemsApplied Mathematicsta111010102 general mathematicsMathematical analysisTriangulation (social science)Numerical Analysis (math.NA)Inverse problem16. Peace & justiceFinite element methodComputer Science::Other010101 applied mathematicselementtimenetelmäModeling and Simulationresistor networksAnalysis of PDEs (math.AP)
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Inverse problems for semilinear elliptic PDE with measurements at a single point

2023

We consider the inverse problem of determining a potential in a semilinear elliptic equation from the knowledge of the Dirichlet-to-Neumann map. For bounded Euclidean domains we prove that the potential is uniquely determined by the Dirichlet-to-Neumann map measured at a single boundary point, or integrated against a fixed measure. This result is valid even when the Dirichlet data is only given on a small subset of the boundary. We also give related uniqueness results on Riemannian manifolds.

osittaisdifferentiaaliyhtälötMathematics - Analysis of PDEsApplied MathematicsGeneral MathematicsFOS: MathematicsMathematics::Analysis of PDEsMathematics::Spectral Theoryinversio-ongelmatAnalysis of PDEs (math.AP)Proceedings of the American Mathematical Society
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The linearized Calderón problem on complex manifolds

2019

International audience; In this note we show that on any compact subdomain of a Kähler manifold that admits sufficiently many global holomorphic functions , the products of harmonic functions form a complete set. This gives a positive answer to the linearized anisotropic Calderón problem on a class of complex manifolds that includes compact subdomains of Stein manifolds and sufficiently small subdomains of Kähler manifolds. Some of these manifolds do not admit limiting Carleman weights, and thus cannot by treated by standard methods for the Calderón problem in higher dimensions. The argument is based on constructing Morse holo-morphic functions with approximately prescribed critical points.…

Class (set theory)Pure mathematicsGeneral MathematicsHolomorphic function01 natural sciencesinversio-ongelmatSet (abstract data type)symbols.namesake[MATH.MATH-AP]Mathematics [math]/Analysis of PDEs [math.AP]0101 mathematics[MATH]Mathematics [math]complex manifoldMathematics::Symplectic GeometryMathematicsosittaisdifferentiaaliyhtälötCalderón problemMathematics::Complex VariablesApplied MathematicsRiemann surface010102 general mathematicsLimitingStandard methodsManifold010101 applied mathematicsHarmonic function[MATH.MATH-DG]Mathematics [math]/Differential Geometry [math.DG]symbolsinverse problemMathematics::Differential Geometrymonistot
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The linearized Calder\'on problem on complex manifolds

2018

In this note we show that on any compact subdomain of a K\"ahler manifold that admits sufficiently many global holomorphic functions, the products of harmonic functions form a complete set. This gives a positive answer to the linearized anisotropic Calder\'on problem on a class of complex manifolds that includes compact subdomains of Stein manifolds and sufficiently small subdomains of K\"ahler manifolds. Some of these manifolds do not admit limiting Carleman weights, and thus cannot by treated by standard methods for the Calder\'on problem in higher dimensions. The argument is based on constructing Morse holomorphic functions with approximately prescribed critical points. This extends resu…

Mathematics - Differential GeometryMathematics - Analysis of PDEsMathematics::Complex VariablesMathematics - Complex VariablesMathematics::Differential GeometryMathematics::Symplectic Geometry
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