A Note on Gamma-Convergence of Tikhonov Functionals for Nonlinear Inverse Problems

• Published in: Numerical functional analysis and optimization Vol. 46; no. 8-9; pp. 658 - 681
• Main Authors: Belenkin, Alexey, Hartz, Michael, Schuster, Thomas
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 04.07.2025; Taylor & Francis Ltd
• Subjects: Approximation; Banach spaces; Convergence; Convergence of minimizing sequences; equi-mild coercivity; Gamma-convergence; Inverse problems; Regularization; Tikhonov functional; Topology; variational regularization
• ISSN: 0163-0563; 1532-2467
• DOI: 10.1080/01630563.2025.2521757

We consider variational regularization of nonlinear inverse problems in Banach spaces using Tikhonov functionals. This article addresses the problem of Γ -convergence of a family of Tikhonov functionals and assertions of the convergence of their respective infima. Such questions arise, if model uncertainties, inaccurate forward operators, finite dimensional approximations of the forward solutions and/or data, etc. make the evaluation of the original functional impossible and, thus, its minimizer not computable. But for applications it is of utmost importance that the minimizer of the replacement functional approximates the original minimizer. Under certain additional conditions this is satisfied if the approximated functionals converge to the original functional in the sense of Γ -convergence. We deduce simple criteria in different topologies which guarantee Γ -convergence as well as convergence of minimizing sequences.