# Mathematics of Computation

Published by the American Mathematical Society since 1960 (published as Mathematical Tables and other Aids to Computation 1943-1959), Mathematics of Computation is devoted to research articles of the highest quality in computational mathematics.

ISSN 1088-6842 (online) ISSN 0025-5718 (print)

The 2020 MCQ for Mathematics of Computation is 1.78.

What is MCQ? The Mathematical Citation Quotient (MCQ) measures journal impact by looking at citations over a five-year period. Subscribers to MathSciNet may click through for more detailed information.

## Guaranteed a posteriori bounds for eigenvalues and eigenvectors: Multiplicities and clustersHTML articles powered by AMS MathViewer

by Eric Cancès, Geneviève Dusson, Yvon Maday, Benjamin Stamm and Martin Vohralík
Math. Comp. 89 (2020), 2563-2611 Request permission

## Abstract:

This paper presents a posteriori error estimates for conforming numerical approximations of eigenvalue clusters of second-order self-adjoint elliptic linear operators with compact resolvent. Given a cluster of eigenvalues, we estimate the error in the sum of the eigenvalues, as well as the error in the eigenvectors represented through the density matrix, i.e., the orthogonal projector on the associated eigenspace. This allows us to deal with degenerate (multiple) eigenvalues within the framework. All the bounds are valid under the only assumption that the cluster is separated from the surrounding smaller and larger eigenvalues; we show how this assumption can be numerically checked. Our bounds are guaranteed and converge with the same speed as the exact errors. They can be turned into fully computable bounds as soon as an estimate on the dual norm of the residual is available, which is presented in two particular cases: the Laplace eigenvalue problem discretized with conforming finite elements, and a Schrödinger operator with periodic boundary conditions of the form \$-\Delta + V\$ discretized with planewaves. For these two cases, numerical illustrations are provided on a set of test problems.
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Similar Articles
• Eric Cancès
• Affiliation: CERMICS, Ecole des Ponts ParisTech, 6 & 8 Av. Pascal, 77455 Marne-la-Vallée, France; and Inria, 2 Rue Simone Iff, 75589 Paris, France
• Email: cances@cermics.enpc.fr
• Geneviève Dusson
• Affiliation: Université Bourgogne Franche-Comté, Laboratoire de Mathématiques de Besançon, UMR CNRS 6623, 16 route de Gray, 25030 Besançon, France
• ORCID: 0000-0002-7160-6064
• Email: genevieve.dusson@math.cnrs.fr
• Affiliation: Sorbonne Université and Université de Paris, CNRS, Laboratoire Jacques-Louis Lions (LJLL), 75005 Paris, France; and Institut Universitaire de France, 75005 Paris, France
• MR Author ID: 117765
• Benjamin Stamm
• Affiliation: Center for Computational Engineering Science, RWTH Aachen University, Aachen, Germany
• MR Author ID: 824171
• ORCID: 0000-0003-3375-483X
• Email: stamm@mathcces.rwth-aachen.de
• Martin Vohralík
• Affiliation: Inria, 2 Rue Simone Iff, 75589 Paris, France; and CERMICS, Ecole des Ponts ParisTech, 6 & 8 Av. Pascal, 77455 Marne-la-Vallée, France
• ORCID: 0000-0002-8838-7689
• Email: martin.vohralik@inria.fr
• Received by editor(s): May 13, 2019
• Received by editor(s) in revised form: March 4, 2020
• Published electronically: July 30, 2020
• Additional Notes: Part of this work has been supported from French state funds managed by the CalSimLab LABEX and the ANR within the “Investissements d’Avenir” program (reference ANR-11-LABX-0037-01). The last author has also received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (Grant Agreement No. 647134 GATIPOR). Part of this work was supported by the French “Investissements d’Avenir” program, project ISITE-BFC (contract ANR-15-IDEX-0003).
The first and third authors acknowledge funding from PICS- CNRS, PHC PROCOPE 2017 (Project No. 37855ZK), and European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 810367).
• © Copyright 2020 American Mathematical Society
• Journal: Math. Comp. 89 (2020), 2563-2611
• MSC (2010): Primary 35P15, 65N15, 65N25, 65N30
• DOI: https://doi.org/10.1090/mcom/3549
• MathSciNet review: 4136540