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arXiv 2104.08386math.AP
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具有二次非线性项的Wave Equations边值问题

Inverse Boundary Value Problems for Wave Equations with Quadratic Nonlinearities

Gunther Uhlmann, Yang Zhang

摘要:

研究了具有边界的Lorentz流形$(M,g)$中的非线性波动方程$\square_g u + w(x,u, \nabla_g u) = 0$的反问题,其中$\nabla_g u$表示梯度,$w(x,u, ξ)$在$ξ$中是光滑的二次方程.在适当的假设下,我们证明了洛伦兹度规$g$的共形类可以从Neumann-to-Dirichlet映射的知识中恢复到同构。在一些附加的条件下,我们可以将度量本身恢复到超同态。此外,我们可以恢复的第二次和第三次二次型的泰勒展开的$w(x,u, ξ)$关于$u$的零形式。

英文摘要:

We study inverse problems for the nonlinear wave equation $\square_g u + w(x,u, \nabla_g u) = 0$ in a Lorentzian manifold $(M,g)$ with boundary, where $\nabla_g u$ denotes the gradient and $w(x,u, ξ)$ is smooth and quadratic in $ξ$. Under appropriate assumptions, we show that the conformal class of the Lorentzian metric $g$ can be recovered up to diffeomorphisms, from the knowledge of the Neumann-to-Dirichlet map. With some additional conditions, we can recover the metric itself up to diffeomorphisms. Moreover, we can recover the second and third quadratic forms in the Taylor expansion of $w(x,u, ξ)$ with respect to $u$ up to null forms.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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