{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,6]],"date-time":"2026-03-06T08:35:11Z","timestamp":1772786111385,"version":"3.50.1"},"reference-count":30,"publisher":"Walter de Gruyter GmbH","issue":"4","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2023,10,1]]},"abstract":"<jats:title>Abstract<\/jats:title>\n               <jats:p>We consider standard tracking-type, distributed elliptic optimal control problems with <jats:inline-formula>\n                     <jats:alternatives>\n                        <m:math xmlns:m=\"http:\/\/www.w3.org\/1998\/Math\/MathML\">\n                           <m:msup>\n                              <m:mi>L<\/m:mi>\n                              <m:mn>2<\/m:mn>\n                           <\/m:msup>\n                        <\/m:math>\n                        <jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/j_cmam-2022-0138_ineq_0001.png\"\/>\n                        <jats:tex-math>L^{2}<\/jats:tex-math>\n                     <\/jats:alternatives>\n                  <\/jats:inline-formula> regularization, and their finite element discretization.\nWe are investigating the <jats:inline-formula>\n                     <jats:alternatives>\n                        <m:math xmlns:m=\"http:\/\/www.w3.org\/1998\/Math\/MathML\">\n                           <m:msup>\n                              <m:mi>L<\/m:mi>\n                              <m:mn>2<\/m:mn>\n                           <\/m:msup>\n                        <\/m:math>\n                        <jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/j_cmam-2022-0138_ineq_0001.png\"\/>\n                        <jats:tex-math>L^{2}<\/jats:tex-math>\n                     <\/jats:alternatives>\n                  <\/jats:inline-formula> error between the finite element approximation <jats:inline-formula>\n                     <jats:alternatives>\n                        <m:math xmlns:m=\"http:\/\/www.w3.org\/1998\/Math\/MathML\">\n                           <m:msub>\n                              <m:mi>u<\/m:mi>\n                              <m:mrow>\n                                 <m:mi>\u03f1<\/m:mi>\n                                 <m:mo>\u2062<\/m:mo>\n                                 <m:mi>h<\/m:mi>\n                              <\/m:mrow>\n                           <\/m:msub>\n                        <\/m:math>\n                        <jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/j_cmam-2022-0138_ineq_0003.png\"\/>\n                        <jats:tex-math>u_{\\varrho h}<\/jats:tex-math>\n                     <\/jats:alternatives>\n                  <\/jats:inline-formula> of the state <jats:inline-formula>\n                     <jats:alternatives>\n                        <m:math xmlns:m=\"http:\/\/www.w3.org\/1998\/Math\/MathML\">\n                           <m:msub>\n                              <m:mi>u<\/m:mi>\n                              <m:mi>\u03f1<\/m:mi>\n                           <\/m:msub>\n                        <\/m:math>\n                        <jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/j_cmam-2022-0138_ineq_0004.png\"\/>\n                        <jats:tex-math>u_{\\varrho}<\/jats:tex-math>\n                     <\/jats:alternatives>\n                  <\/jats:inline-formula> and the desired state (target) <jats:inline-formula>\n                     <jats:alternatives>\n                        <m:math xmlns:m=\"http:\/\/www.w3.org\/1998\/Math\/MathML\">\n                           <m:mover accent=\"true\">\n                              <m:mi>u<\/m:mi>\n                              <m:mo>\u00af<\/m:mo>\n                           <\/m:mover>\n                        <\/m:math>\n                        <jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/j_cmam-2022-0138_ineq_0005.png\"\/>\n                        <jats:tex-math>\\overline{u}<\/jats:tex-math>\n                     <\/jats:alternatives>\n                  <\/jats:inline-formula> in terms of the regularization parameter \ud835\udf1a and the mesh size \u210e that leads to the optimal choice <jats:inline-formula>\n                     <jats:alternatives>\n                        <m:math xmlns:m=\"http:\/\/www.w3.org\/1998\/Math\/MathML\">\n                           <m:mrow>\n                              <m:mi>\u03f1<\/m:mi>\n                              <m:mo>=<\/m:mo>\n                              <m:msup>\n                                 <m:mi>h<\/m:mi>\n                                 <m:mn>4<\/m:mn>\n                              <\/m:msup>\n                           <\/m:mrow>\n                        <\/m:math>\n                        <jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/j_cmam-2022-0138_ineq_0006.png\"\/>\n                        <jats:tex-math>\\varrho=h^{4}<\/jats:tex-math>\n                     <\/jats:alternatives>\n                  <\/jats:inline-formula>.\nIt turns out that, for this choice of the regularization parameter, we can devise simple Jacobi-like preconditioned MINRES or Bramble\u2013Pasciak CG methods that allow us to solve the reduced discrete optimality system in asymptotically optimal complexity with respect to the arithmetical operations and memory demand.\nThe theoretical results are confirmed by several benchmark problems with targets of various regularities including discontinuous targets.<\/jats:p>","DOI":"10.1515\/cmam-2022-0138","type":"journal-article","created":{"date-parts":[[2023,2,17]],"date-time":"2023-02-17T13:09:28Z","timestamp":1676639368000},"page":"989-1005","source":"Crossref","is-referenced-by-count":7,"title":["Robust Finite Element Discretization and Solvers for Distributed Elliptic Optimal Control Problems"],"prefix":"10.1515","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3797-7475","authenticated-orcid":false,"given":"Ulrich","family":"Langer","sequence":"first","affiliation":[{"name":"Institute of Computational Mathematics , Johannes Kepler University Linz , Altenberger Stra\u00dfe 69, 4040 Linz , Austria"}]},{"given":"Richard","family":"L\u00f6scher","sequence":"additional","affiliation":[{"name":"Institut f\u00fcr Angewandte Mathematik , Technische Universit\u00e4t Graz , Steyrergasse 30, 8010 Graz , Austria"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2552-3022","authenticated-orcid":false,"given":"Olaf","family":"Steinbach","sequence":"additional","affiliation":[{"name":"Institut f\u00fcr Angewandte Mathematik , Technische Universit\u00e4t Graz , Steyrergasse 30, 8010 Graz , Austria"}]},{"given":"Huidong","family":"Yang","sequence":"additional","affiliation":[{"name":"Computational Science Center , Universit\u00e4t Wien , Oskar-Morgenstern-Platz 1, 1090 Wien , Austria"}]}],"member":"374","published-online":{"date-parts":[[2023,2,18]]},"reference":[{"key":"2025011504140378776_j_cmam-2022-0138_ref_001","doi-asserted-by":"crossref","unstructured":"O. 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