Pointwise A Posteriori Error Estimators for Multiple and Clustered Eigenvalue Computations

Fuente: arXiv
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Main Authors: Li, Zhenglei, Liang, Qigang, Xu, Xuejun
Format: Preprint
Published: 2025
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author Li, Zhenglei
Liang, Qigang
Xu, Xuejun
author_facet Li, Zhenglei
Liang, Qigang
Xu, Xuejun
contents In this work, we propose an a pointwise a posteriori error estimator for conforming finite element approximations of eigenfunctions corresponding to multiple and clustered eigenvalues of elliptic operators. It is proven that the pointwise a posteriori error estimator is reliable and efficient, up to some logarithmic factors of the mesh size. The constants involved in the reliability and efficiency are independent of the gaps among the targeted eigenvalues, the mesh size and the number of mesh level. Specially, we obtain a by-product that edge residuals dominate the a posteriori error in the sense of $L^{\infty}$-norm when the linear element is used. With the aid of the weighted Sobolev stability of the $L^2$-projection, we also propose a new method to prove the reliability of the a posteriori error estimator for higher order finite elements. A key ingredient in the a posteriori error analysis is some new estimates for regularized derivative Green's functions. Some numerical experiments verify our theoretical results.
format Preprint
id arxiv_https___arxiv_org_abs_2511_08259
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Pointwise A Posteriori Error Estimators for Multiple and Clustered Eigenvalue Computations
Li, Zhenglei
Liang, Qigang
Xu, Xuejun
Numerical Analysis
In this work, we propose an a pointwise a posteriori error estimator for conforming finite element approximations of eigenfunctions corresponding to multiple and clustered eigenvalues of elliptic operators. It is proven that the pointwise a posteriori error estimator is reliable and efficient, up to some logarithmic factors of the mesh size. The constants involved in the reliability and efficiency are independent of the gaps among the targeted eigenvalues, the mesh size and the number of mesh level. Specially, we obtain a by-product that edge residuals dominate the a posteriori error in the sense of $L^{\infty}$-norm when the linear element is used. With the aid of the weighted Sobolev stability of the $L^2$-projection, we also propose a new method to prove the reliability of the a posteriori error estimator for higher order finite elements. A key ingredient in the a posteriori error analysis is some new estimates for regularized derivative Green's functions. Some numerical experiments verify our theoretical results.
title Pointwise A Posteriori Error Estimators for Multiple and Clustered Eigenvalue Computations
topic Numerical Analysis
url https://arxiv.org/abs/2511.08259