{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,6]],"date-time":"2026-03-06T08:42:11Z","timestamp":1772786531304,"version":"3.50.1"},"reference-count":37,"publisher":"Springer Science and Business Media LLC","issue":"2","license":[{"start":{"date-parts":[[2024,4,1]],"date-time":"2024-04-01T00:00:00Z","timestamp":1711929600000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2024,4,10]],"date-time":"2024-04-10T00:00:00Z","timestamp":1712707200000},"content-version":"vor","delay-in-days":9,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"funder":[{"DOI":"10.13039\/100008332","name":"Graz University of Technology","doi-asserted-by":"crossref","id":[{"id":"10.13039\/100008332","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Adv Comput Math"],"published-print":{"date-parts":[[2024,4]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>As in our previous work (<jats:italic>SINUM<\/jats:italic>59(2):660\u2013674, 2021) we consider space-time tracking optimal control problems for linear parabolic initial boundary value problems that are given in the space-time cylinder<jats:inline-formula><jats:alternatives><jats:tex-math>$$Q = \\Omega \\times (0,T)$$<\/jats:tex-math><mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mrow><mml:mi>Q<\/mml:mi><mml:mo>=<\/mml:mo><mml:mi>\u03a9<\/mml:mi><mml:mo>\u00d7<\/mml:mo><mml:mo>(<\/mml:mo><mml:mn>0<\/mml:mn><mml:mo>,<\/mml:mo><mml:mi>T<\/mml:mi><mml:mo>)<\/mml:mo><\/mml:mrow><\/mml:math><\/jats:alternatives><\/jats:inline-formula>, and that are controlled by the right-hand side<jats:inline-formula><jats:alternatives><jats:tex-math>$$z_\\varrho $$<\/jats:tex-math><mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:msub><mml:mi>z<\/mml:mi><mml:mi>\u03f1<\/mml:mi><\/mml:msub><\/mml:math><\/jats:alternatives><\/jats:inline-formula>from the Bochner space<jats:inline-formula><jats:alternatives><jats:tex-math>$$L^2(0,T;H^{-1}(\\Omega ))$$<\/jats:tex-math><mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mrow><mml:msup><mml:mi>L<\/mml:mi><mml:mn>2<\/mml:mn><\/mml:msup><mml:mrow><mml:mo>(<\/mml:mo><mml:mn>0<\/mml:mn><mml:mo>,<\/mml:mo><mml:mi>T<\/mml:mi><mml:mo>\u037e<\/mml:mo><mml:msup><mml:mi>H<\/mml:mi><mml:mrow><mml:mo>-<\/mml:mo><mml:mn>1<\/mml:mn><\/mml:mrow><\/mml:msup><mml:mrow><mml:mo>(<\/mml:mo><mml:mi>\u03a9<\/mml:mi><mml:mo>)<\/mml:mo><\/mml:mrow><mml:mo>)<\/mml:mo><\/mml:mrow><\/mml:mrow><\/mml:math><\/jats:alternatives><\/jats:inline-formula>. So it is natural to replace the usual<jats:inline-formula><jats:alternatives><jats:tex-math>$$L^2(Q)$$<\/jats:tex-math><mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mrow><mml:msup><mml:mi>L<\/mml:mi><mml:mn>2<\/mml:mn><\/mml:msup><mml:mrow><mml:mo>(<\/mml:mo><mml:mi>Q<\/mml:mi><mml:mo>)<\/mml:mo><\/mml:mrow><\/mml:mrow><\/mml:math><\/jats:alternatives><\/jats:inline-formula>norm regularization by the energy regularization in the<jats:inline-formula><jats:alternatives><jats:tex-math>$$L^2(0,T;H^{-1}(\\Omega ))$$<\/jats:tex-math><mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mrow><mml:msup><mml:mi>L<\/mml:mi><mml:mn>2<\/mml:mn><\/mml:msup><mml:mrow><mml:mo>(<\/mml:mo><mml:mn>0<\/mml:mn><mml:mo>,<\/mml:mo><mml:mi>T<\/mml:mi><mml:mo>\u037e<\/mml:mo><mml:msup><mml:mi>H<\/mml:mi><mml:mrow><mml:mo>-<\/mml:mo><mml:mn>1<\/mml:mn><\/mml:mrow><\/mml:msup><mml:mrow><mml:mo>(<\/mml:mo><mml:mi>\u03a9<\/mml:mi><mml:mo>)<\/mml:mo><\/mml:mrow><mml:mo>)<\/mml:mo><\/mml:mrow><\/mml:mrow><\/mml:math><\/jats:alternatives><\/jats:inline-formula>norm. We derive new a priori estimates for the error<jats:inline-formula><jats:alternatives><jats:tex-math>$$\\Vert \\widetilde{u}_{\\varrho h} - \\overline{u}\\Vert _{L^2(Q)}$$<\/jats:tex-math><mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mrow><mml:mrow><mml:mo>\u2016<\/mml:mo><\/mml:mrow><mml:msub><mml:mover><mml:mi>u<\/mml:mi><mml:mo>~<\/mml:mo><\/mml:mover><mml:mrow><mml:mi>\u03f1<\/mml:mi><mml:mi>h<\/mml:mi><\/mml:mrow><\/mml:msub><mml:mo>-<\/mml:mo><mml:mover><mml:mi>u<\/mml:mi><mml:mo>\u00af<\/mml:mo><\/mml:mover><mml:msub><mml:mrow><mml:mo>\u2016<\/mml:mo><\/mml:mrow><mml:mrow><mml:msup><mml:mi>L<\/mml:mi><mml:mn>2<\/mml:mn><\/mml:msup><mml:mrow><mml:mo>(<\/mml:mo><mml:mi>Q<\/mml:mi><mml:mo>)<\/mml:mo><\/mml:mrow><\/mml:mrow><\/mml:msub><\/mml:mrow><\/mml:math><\/jats:alternatives><\/jats:inline-formula>between the computed state<jats:inline-formula><jats:alternatives><jats:tex-math>$$\\widetilde{u}_{\\varrho h}$$<\/jats:tex-math><mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:msub><mml:mover><mml:mi>u<\/mml:mi><mml:mo>~<\/mml:mo><\/mml:mover><mml:mrow><mml:mi>\u03f1<\/mml:mi><mml:mi>h<\/mml:mi><\/mml:mrow><\/mml:msub><\/mml:math><\/jats:alternatives><\/jats:inline-formula>and the desired state<jats:inline-formula><jats:alternatives><jats:tex-math>$$\\overline{u}$$<\/jats:tex-math><mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mover><mml:mi>u<\/mml:mi><mml:mo>\u00af<\/mml:mo><\/mml:mover><\/mml:math><\/jats:alternatives><\/jats:inline-formula>in terms of the regularization parameter<jats:inline-formula><jats:alternatives><jats:tex-math>$$\\varrho $$<\/jats:tex-math><mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mi>\u03f1<\/mml:mi><\/mml:math><\/jats:alternatives><\/jats:inline-formula>and the space-time finite element mesh size<jats:italic>h<\/jats:italic>, and depending on the regularity of the desired state<jats:inline-formula><jats:alternatives><jats:tex-math>$$\\overline{u}$$<\/jats:tex-math><mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mover><mml:mi>u<\/mml:mi><mml:mo>\u00af<\/mml:mo><\/mml:mover><\/mml:math><\/jats:alternatives><\/jats:inline-formula>. These new estimates lead to the optimal choice<jats:inline-formula><jats:alternatives><jats:tex-math>$$\\varrho = h^2$$<\/jats:tex-math><mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:mrow><mml:mi>\u03f1<\/mml:mi><mml:mo>=<\/mml:mo><mml:msup><mml:mi>h<\/mml:mi><mml:mn>2<\/mml:mn><\/mml:msup><\/mml:mrow><\/mml:math><\/jats:alternatives><\/jats:inline-formula>. The approximate state<jats:inline-formula><jats:alternatives><jats:tex-math>$$\\widetilde{u}_{\\varrho h}$$<\/jats:tex-math><mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><mml:msub><mml:mover><mml:mi>u<\/mml:mi><mml:mo>~<\/mml:mo><\/mml:mover><mml:mrow><mml:mi>\u03f1<\/mml:mi><mml:mi>h<\/mml:mi><\/mml:mrow><\/mml:msub><\/mml:math><\/jats:alternatives><\/jats:inline-formula>is computed by means of a space-time finite element method using piecewise linear and continuous basis functions on completely unstructured simplicial meshes for<jats:italic>Q<\/jats:italic>. The theoretical results are quantitatively illustrated by a series of numerical examples in two and three space dimensions. We also provide performance studies for different solvers.<\/jats:p>","DOI":"10.1007\/s10444-024-10123-w","type":"journal-article","created":{"date-parts":[[2024,4,10]],"date-time":"2024-04-10T05:01:52Z","timestamp":1712725312000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Robust space-time finite element methods for parabolic distributed optimal control problems with energy regularization"],"prefix":"10.1007","volume":"50","author":[{"given":"Ulrich","family":"Langer","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Olaf","family":"Steinbach","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Huidong","family":"Yang","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"297","published-online":{"date-parts":[[2024,4,10]]},"reference":[{"issue":"1","key":"10123_CR1","doi-asserted-by":"publisher","first-page":"343","DOI":"10.1093\/imanum\/drs001","volume":"33","author":"Z-Z Bai","year":"2013","unstructured":"Bai, Z.-Z., Benzi, M., Chen, F., Wang, Z.-Q.: Preconditioned MHSS iteration methods for a class of block two-by-two linear systems with applications to distributed control problems. IMA J. Numer. Anal. 33(1), 343\u2013369 (2013)","journal-title":"IMA J. Numer. Anal."},{"key":"10123_CR2","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1017\/S0962492904000212","volume":"14","author":"M Benzi","year":"2005","unstructured":"Benzi, M., Golub, G.H., Liesen, J.: Numerical solution of saddle point problems. Acta Numer 14, 1\u2013137 (2005)","journal-title":"Acta Numer"},{"key":"10123_CR3","doi-asserted-by":"publisher","first-page":"767","DOI":"10.1007\/s10589-023-00507-x","volume":"86","author":"N Beranek","year":"2023","unstructured":"Beranek, N., Reinhold, M.A., Urban, K.: A space-time variational method for optimal control problems: Well-posedness, stability and numerical solution. Comput. Optim. Appl. 86, 767\u2013794 (2023)","journal-title":"Comput. Optim. Appl."},{"key":"10123_CR4","doi-asserted-by":"publisher","first-page":"355","DOI":"10.1007\/BF02238487","volume":"55","author":"J Bey","year":"1995","unstructured":"Bey, J.: Tetrahedral grid refinement. Computing 55, 355\u2013378 (1995)","journal-title":"Computing"},{"key":"10123_CR5","doi-asserted-by":"crossref","unstructured":"Borz\u00ec, A., Schulz, V.: Computational optimization of systems governed by partial differential equations, vol.\u00a08 of Computational Science & Engineering. SIAM, (2011)","DOI":"10.1137\/1.9781611972054"},{"issue":"181","key":"10123_CR6","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1090\/S0025-5718-1988-0917816-8","volume":"50","author":"JH Bramble","year":"1988","unstructured":"Bramble, J.H., Pasciak, J.E.: A preconditioning technique for indefinite systems resulting from mixed approximations of elliptic problems. Math. Comp. 50(181), 1\u201317 (1988)","journal-title":"Math. Comp."},{"key":"10123_CR7","doi-asserted-by":"crossref","unstructured":"Brenner, S., Scott, R.: The Mathematical Theory of Finite Element Methods. Texts Appl. Math. vol. 15. Springer, New York (2008)","DOI":"10.1007\/978-0-387-75934-0"},{"key":"10123_CR8","doi-asserted-by":"publisher","first-page":"319","DOI":"10.1007\/s40324-017-0121-5","volume":"74","author":"E Casas","year":"2017","unstructured":"Casas, E.: A review on sparse solutions in optimal control of partial differential equations. SeMA Journal 74, 319\u2013344 (2017)","journal-title":"SeMA Journal"},{"issue":"4","key":"10123_CR9","doi-asserted-by":"publisher","first-page":"415","DOI":"10.1515\/cmam-2013-0016","volume":"13","author":"E Casas","year":"2013","unstructured":"Casas, E., Ryll, C., Tr\u00f6ltzsch, F.: Sparse optimal control of the Schl\u00f6gl and FitzHugh-Nagumo systems. Comput. Methods Appl. Math. 13(4), 415\u2013442 (2013)","journal-title":"Comput. Methods Appl. Math."},{"key":"10123_CR10","doi-asserted-by":"publisher","DOI":"10.1007\/978-1-4757-4355-5","volume-title":"Theory and Practice of Finite Elements","author":"A Ern","year":"2004","unstructured":"Ern, A., Guermond, J.-L.: Theory and Practice of Finite Elements. Springer, New York (2004)"},{"key":"10123_CR11","doi-asserted-by":"crossref","unstructured":"F\u00fchrer, T., Karkulik, M.: Space-time finite element methods for parabolic distributed optimal control problems. Comput. Methods Appl. Math., accepted, (2024)","DOI":"10.1515\/cmam-2023-0087"},{"key":"10123_CR12","unstructured":"Gangl, P., L\u00f6scher, R., Steinbach, O.: Regularization and finite element error estimates for elliptic distributed optimal control problems with energy regularization and state or control constraints (2023). arXiv:2306.15316"},{"key":"10123_CR13","doi-asserted-by":"crossref","unstructured":"Gantner, G., Stevenson, R.: Applications of a space-time FOSLS formulation for parabolic PDEs. IMA J. Numer. Anal. 44(1), 58\u201382 (2024)","DOI":"10.1093\/imanum\/drad012"},{"issue":"2","key":"10123_CR14","doi-asserted-by":"publisher","first-page":"111","DOI":"10.1515\/jnum-2012-0005","volume":"20","author":"W Gong","year":"2012","unstructured":"Gong, W., Hinze, M., Zhou, Z.: Space-time finite element approximation of parabolic optimal control problems. J. Numer. Math. 20(2), 111\u2013145 (2012)","journal-title":"J. Numer. Math."},{"issue":"3","key":"10123_CR15","doi-asserted-by":"publisher","first-page":"1150","DOI":"10.1137\/100806382","volume":"49","author":"M Gunzburger","year":"2011","unstructured":"Gunzburger, M., Kunoth, A.: Space-time adaptive wavelet methods for optimal control problems constrained by parabolic evolution equations. SIAM J. Control. Optim. 49(3), 1150\u20131170 (2011)","journal-title":"SIAM J. Control. Optim."},{"key":"10123_CR16","doi-asserted-by":"publisher","DOI":"10.1007\/978-1-4020-8839-1_3","volume-title":"Optimization with PDE Constraints","author":"M Hinze","year":"2009","unstructured":"Hinze, M., Pinnau, R., Ulbrich, M., Ulbrich, S.: Optimization with PDE Constraints, vol. 23. Springer, Berlin (2009)"},{"key":"10123_CR17","doi-asserted-by":"crossref","unstructured":"John V.: Finite Element Methods for Incompressible Flow Problems, vol.\u00a051 of Springer Series in Computational Mathematics. Springer, (2016)","DOI":"10.1007\/978-3-319-45750-5"},{"key":"10123_CR18","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1016\/j.camwa.2024.02.006","volume":"160","author":"U Langer","year":"2024","unstructured":"Langer, U., L\u00f6scher, R., Steinbach, O., Yang, H.: An adaptive finite element method for distributed elliptic optimal control problems with variable energy regularization. Comput. Math. Appl. 160, 1\u201314 (2024)","journal-title":"Comput. Math. Appl."},{"issue":"4","key":"10123_CR19","doi-asserted-by":"publisher","first-page":"247","DOI":"10.1515\/jnma-2021-0059","volume":"30","author":"U Langer","year":"2022","unstructured":"Langer, U., Schafelner, A.: Adaptive space-time finite element methods for parabolic optimal control problems. J. Numer. Math. 30(4), 247\u2013266 (2022)","journal-title":"J. Numer. Math."},{"issue":"2","key":"10123_CR20","doi-asserted-by":"publisher","first-page":"660","DOI":"10.1137\/20M1332980","volume":"59","author":"U Langer","year":"2021","unstructured":"Langer, U., Steinbach, O., Tr\u00f6ltzsch, F., Yang, H.: Space-time finite element discretization of parabolic optimal control problems with energy regularization. SIAM J. Numer. Anal. 59(2), 660\u2013674 (2021)","journal-title":"SIAM J. Numer. Anal."},{"issue":"2","key":"10123_CR21","doi-asserted-by":"publisher","first-page":"A744","DOI":"10.1137\/20M1330452","volume":"43","author":"U Langer","year":"2021","unstructured":"Langer, U., Steinbach, O., Tr\u00f6ltzsch, F., Yang, H.: Unstructured space-time finite element methods for optimal control of parabolic equation. SIAM J. Sci. Comput. 43(2), A744\u2013A771 (2021)","journal-title":"SIAM J. Sci. Comput."},{"issue":"1","key":"10123_CR22","doi-asserted-by":"publisher","first-page":"97","DOI":"10.1515\/cmam-2021-0169","volume":"22","author":"U Langer","year":"2022","unstructured":"Langer, U., Steinbach, O., Yang, H.: Robust discretization and solvers for elliptic optimal control problems with energy regularization. Comput. Meth. Appl. Math. 22(1), 97\u2013111 (2022)","journal-title":"Comput. Meth. Appl. Math."},{"key":"10123_CR23","volume-title":"Contr\u00f4le optimal de syst\u00e8mes gouvern\u00e9s par des \u00e9quations aux d\u00e9riv\u00e9es partielles","author":"JL Lions","year":"1968","unstructured":"Lions, J.L.: Contr\u00f4le optimal de syst\u00e8mes gouvern\u00e9s par des \u00e9quations aux d\u00e9riv\u00e9es partielles. Dunod Gauthier-Villars, Paris (1968)"},{"key":"10123_CR24","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-642-65217-2","volume-title":"Non-homogeneous boundary value problems and applications I","author":"J-L Lions","year":"1972","unstructured":"Lions, J.-L., Magenes, E.: Non-homogeneous boundary value problems and applications I. Springer, New York-Heidelberg (1972)"},{"issue":"1","key":"10123_CR25","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1002\/nla.716","volume":"18","author":"K-A Mardal","year":"2011","unstructured":"Mardal, K.-A., Winther, R.: Preconditioning discretizations of systems of partial differential equations. Numer. Linear Algebra Appl. 18(1), 1\u201340 (2011)","journal-title":"Numer. Linear Algebra Appl."},{"key":"10123_CR26","doi-asserted-by":"publisher","first-page":"4176","DOI":"10.1002\/mma.7021","volume":"44","author":"M Neum\u00fcller","year":"2021","unstructured":"Neum\u00fcller, M., Steinbach, O.: Regularization error estimates for distributed control problems in energy spaces. Math. Methods Appl. Sci. 44, 4176\u20134191 (2021)","journal-title":"Math. Methods Appl. Sci."},{"issue":"1","key":"10123_CR27","doi-asserted-by":"publisher","first-page":"81","DOI":"10.1002\/nla.1863","volume":"21","author":"JW Pearson","year":"2014","unstructured":"Pearson, J.W., Stoll, M., Wathen, A.J.: Preconditioners for state-constrained optimal control problems with Moreau-Yosida penalty function. Numer. Linear Algebra Appl. 21(1), 81\u201397 (2014)","journal-title":"Numer. Linear Algebra Appl."},{"key":"10123_CR28","doi-asserted-by":"publisher","first-page":"73","DOI":"10.1137\/1.9781611971057.ch4","volume-title":"Multigrid Methods","author":"JW Ruge","year":"1987","unstructured":"Ruge, J.W., St\u00fcben, K.: Algebraic multigrid (AMG). In: McCormick, S.F. (ed.) Multigrid Methods, pp. 73\u2013130. SIAM, Philadelphia (1987)"},{"key":"10123_CR29","doi-asserted-by":"publisher","first-page":"752","DOI":"10.1137\/060660977","volume":"29","author":"J Sch\u00f6berl","year":"2007","unstructured":"Sch\u00f6berl, J., Zulehner, W.: Symmetric indefinite preconditioners for saddle point problems with applications to PDE-constrained optimization problems. SIAM J. Matrix Anal. Appl. 29, 752\u2013773 (2007)","journal-title":"SIAM J. Matrix Anal. Appl."},{"issue":"4","key":"10123_CR30","doi-asserted-by":"publisher","first-page":"207","DOI":"10.1007\/s00791-008-0094-0","volume":"11","author":"V Schulz","year":"2008","unstructured":"Schulz, V., Wittum, G.: Transforming smoothers for pde constrained optimization problems. Comput. Visual. Sci. 11(4), 207\u2013219 (2008)","journal-title":"Comput. Visual. Sci."},{"issue":"4","key":"10123_CR31","doi-asserted-by":"publisher","first-page":"551","DOI":"10.1515\/cmam-2015-0026","volume":"15","author":"O Steinbach","year":"2015","unstructured":"Steinbach, O.: Space-time finite element methods for parabolic problems. Comput. Meth. Appl. Math. 15(4), 551\u2013566 (2015)","journal-title":"Comput. Meth. Appl. Math."},{"key":"10123_CR32","doi-asserted-by":"publisher","first-page":"154","DOI":"10.1553\/etna_vol52s154","volume":"52","author":"O Steinbach","year":"2020","unstructured":"Steinbach, O., Zank, M.: Coercive space-time finite element methods for initial boundary value problems. Electron. Trans. Numer. Anal. 52, 154\u2013194 (2020)","journal-title":"Electron. Trans. Numer. Anal."},{"issue":"261","key":"10123_CR33","doi-asserted-by":"publisher","first-page":"227","DOI":"10.1090\/S0025-5718-07-01959-X","volume":"77","author":"R Stevenson","year":"2008","unstructured":"Stevenson, R.: The completion of locally refined simplicial partitions created by bisection. Math. Comput. 77(261), 227\u2013241 (2008)","journal-title":"Math. Comput."},{"key":"10123_CR34","unstructured":"Tartar, L.: An Introduction to Sobolev Spaces and Interpolation Spaces. Lecture Notes of the Unione Matematica Italiana, vol. 3. Springer, Berlin (2007)"},{"key":"10123_CR35","doi-asserted-by":"crossref","unstructured":"Tr\u00f6ltzsch, F.: Optimal control of partial differential equations: Theory, methods and applications. Graduate Studies in Mathematics, vol. 112. American Mathematical Society, Providence, Rhode Island (2010)","DOI":"10.1090\/gsm\/112\/07"},{"key":"10123_CR36","doi-asserted-by":"publisher","DOI":"10.1007\/978-1-4612-0981-2","volume-title":"Nonlinear Functional Analysis and its Applications II\/B: Nonlinear Monotone Operators","author":"E Zeidler","year":"1990","unstructured":"Zeidler, E.: Nonlinear Functional Analysis and its Applications II\/B: Nonlinear Monotone Operators. Springer, New York (1990)"},{"issue":"2","key":"10123_CR37","doi-asserted-by":"publisher","first-page":"536","DOI":"10.1137\/100814767","volume":"32","author":"W Zulehner","year":"2011","unstructured":"Zulehner, W.: Nonstandard norms and robust estimates for saddle point problems. SIAM J. Matrix Anal. Appl. 32(2), 536\u2013560 (2011)","journal-title":"SIAM J. Matrix Anal. Appl."}],"container-title":["Advances in Computational Mathematics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/link.springer.com\/content\/pdf\/10.1007\/s10444-024-10123-w.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/link.springer.com\/article\/10.1007\/s10444-024-10123-w\/fulltext.html","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/link.springer.com\/content\/pdf\/10.1007\/s10444-024-10123-w.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,11,16]],"date-time":"2024-11-16T00:17:08Z","timestamp":1731716228000},"score":1,"resource":{"primary":{"URL":"https:\/\/link.springer.com\/10.1007\/s10444-024-10123-w"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,4]]},"references-count":37,"journal-issue":{"issue":"2","published-print":{"date-parts":[[2024,4]]}},"alternative-id":["10123"],"URL":"https:\/\/doi.org\/10.1007\/s10444-024-10123-w","relation":{},"ISSN":["1019-7168","1572-9044"],"issn-type":[{"value":"1019-7168","type":"print"},{"value":"1572-9044","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,4]]},"assertion":[{"value":"2 January 2023","order":1,"name":"received","label":"Received","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"7 March 2024","order":2,"name":"accepted","label":"Accepted","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"10 April 2024","order":3,"name":"first_online","label":"First Online","group":{"name":"ArticleHistory","label":"Article History"}},{"order":1,"name":"Ethics","group":{"name":"EthicsHeading","label":"Declarations"}},{"value":"The authors declare no competing interests.","order":2,"name":"Ethics","group":{"name":"EthicsHeading","label":"Conflict of interest"}}],"article-number":"24"}}