Hearing the Triangles: A Numerical Perspective

Hearing the Triangles: A Numerical Perspective

Year:    2024

Author:    Wei Gong, Xiaodong Liu, Jing Wang

CSIAM Transactions on Applied Mathematics, Vol. 5 (2024), Iss. 1 : pp. 58–72

Abstract

We introduce a two-step numerical scheme for reconstructing the shape of a triangle by its Dirichlet spectrum. With the help of the asymptotic behavior of the heat trace, the first step is to determine the area, the perimeter, and the sum of the reciprocals of the angles of the triangle. The shape is then reconstructed, in the second step, by an application of the Newton’s iterative method or the Levenberg-Marquardt algorithm for solving a nonlinear system of equations on the angles. Numerically, we have used only finitely many eigenvalues to reconstruct the triangles. To our best knowledge, this is the first numerical simulation for the classical inverse spectrum problem in the plane. In addition, we give a counter example to show that, even if we have infinitely many eigenvalues, the shape of a quadrilateral may not be heard.

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Journal Article Details

Publisher Name:    Global Science Press

Language:    English

DOI:    https://doi.org/10.4208/csiam-am.SO-2023-0027

CSIAM Transactions on Applied Mathematics, Vol. 5 (2024), Iss. 1 : pp. 58–72

Published online:    2024-01

AMS Subject Headings:    Global Science Press

Copyright:    COPYRIGHT: © Global Science Press

Pages:    15

Keywords:    Inverse spectral problems Newton iteration Vandermonde matrix ill-posedness triangles.

Author Details

Wei Gong

Xiaodong Liu

Jing Wang