Publications

Scientific Articles in Journals and Books

Submitted
•	Constantin Christof, Julia Kowalczyk: On the Omnipresence of Spurious Local Minima in Certain Neural Network Training Problems Submitted, Preprint arXiv: 2202.12262, 2022.
•	Martin Brokate, Constantin Christof: Strong Stationarity Conditions for Optimal Control Problems Governed by a Rate-Independent Evolution Variational Inequality Submitted, Preprint arXiv: 2205.01196, 2022.
•	Constantin Christof, Gerd Wachsmuth: Lipschitz Stability and Hadamard Directional Differentiability for Elliptic and Parabolic Obstacle-Type Quasi-Variational Inequalities Submitted, Preprint arXiv: 2105.05895, 2021.
•	Constantin Christof, Gerd Wachsmuth: Semismoothness for solution operators of obstacle-type variational inequalities with applications in optimal control Submitted, Preprint arXiv: 2112.12018, 2021.

Appeared 2022
•	Constantin Christof, Dominik Hafemeyer: On the Nonuniqueness and Instability of Solutions of Tracking-Type Optimal Control Problems American Institute of Mathematical Sciences, Mathematical Control & Related Fields, 12(2): pp. 421-431, 2022. (doi:10.3934/mcrf.2021028)
•	Dominik Hafemeyer, Florian Mannel: A path-following inexact Newton method for PDE-constrained optimal control in BV Computational Optimization and Applications, 2022. (doi:10.1007/s10589-022-00370-2)
•	Niklas Behringer, Dmitriy Leykekhman, Boris Vexler: Fully discrete best approximation type estimates in L∞(I;L2(Ω)d) for finite element discretizations of the transient Stokes equations IMA Journal of Numerical Analysis , 2022. (doi:10.1093/imanum/drac009)

Appeared 2021
•	Lukas Failer, Thomas Richter: A Newton multigrid framework for optimal control of fluid-structure interactions Optimization and Engineering, 22, pp. 2009-2037, 2021. (doi:10.1007/s11081-020-09498-8)
•	Sebastian Engel, Philip Trautmann, Boris Vexler: Optimal finite element error estimates for an optimal control problem governed by the wave equation with controls of bounded variation IMA Journal of Numerical Analysis, 41(4), pp. 2639–2667, 2021. (doi:10.1093/imanum/draa032)
•	Constantin Christof, Gerd Wachsmuth: On Second-Order Optimality Conditions for Optimal Control Problems Governed by the Obstacle Problem Optimization, A Journal of Mathematical Programming and Operations Research, 70 (10), pp. 2247-2287, 2021. (doi:10.1080/02331934.2020.1778686)
•	Constantin Christof, Georg Müller: Multiobjective optimal control of a non-smooth semilinear elliptic partial differential equation ESAIM: Control, Optimisation and Calculus of Variations, 27, 2021. (doi:10.1051/cocv/2020060)
•	Constantin Christof, Boris Vexler: New regularity results and finite element error estimates for a class of parabolic optimal control problems with pointwise state constraints ESAIM: Control, Optimisation and Calculus of Variations, 27, 2021. (doi:10.1051/cocv/2020059)
•	Niklas Behringer: Improved error estimates for optimal control of the Stokes problem with pointwise tracking in three dimensions American Institue of Mathematical Sciences, Mathematical Control & Related Fields, 11(2), pp. 313-328, 2021. (doi:10.3934/mcrf.2020038)
•	Constantin Christof: On the Stability Properties and the Optimization Landscape of Training Problems with Squared Loss for Neural Networks and General Nonlinear Conic Approximation Schemes Journal of Machine Learning Research, 22(263), pp.1-77, (http://jmlr.org/papers/v22/20-1259.html), 2021.

Appeared 2020
•	Constantin Christof, Gerd Wachsmuth: Differential Sensitivity Analysis of Variational Inequalities with Locally Lipschitz Continuous Solution Operators Applied Mathematics & Optimization, 81, pp.23–62, 2020. (doi:10.1007/s00245-018-09553-y)
•	Constantin Christof, Christian Meyer, Juan Carlos De los Reyes: A Non-Smooth Trust Region Method for Locally Lipschitz Functions with Application to Optimization Problems Constrained by Variational Inequalities SIAM Journal on Optimization, 30(3), pp 2163–2196, 2020. (doi:10.1137/18M1164925)
•	Thomas Apel, Johannes Pfefferer, Sergej Rogovs, Max Winkler: Maximum norm error estimates for Neumann boundary value problems on graded meshes IMA Journal of Numerical Analysis, 40(1), pp. 474-497, Preprint arXiv: 1804.10904, 2020.
•	Konstantin Pieper, Bao Quoc Tang, Philip Trautmann, Daniel Walter: Inverse point source location with the Helmholtz Equation on a bounded domain Computational Optimization and Apllications, 77, pp. 213-249, 2020. (doi:10.1007/s10589-020-00205-y)
•	Lucas Bonifacius, Karl Kunisch: Time-optimality by distance-optimality for parabolic control systems ESAIM: Mathematical Modelling and Numerical Analysis, 54(1), pp. 79-103, 2020. (doi:10.1051/m2an/2019046)
•	Dominik Hafemeyer, Christian Kahle, Johannes Pfefferer: Finite element error estimates in L2 for regularized discrete approximations to the obstacle problem Numerische Mathematik, 144(1), pp. 133–156, 2020. (doi:10.1007/s00211-019-01081-3)
•	Constantin Christof: Gradient-Based Solution Algorithms for a Class of Bilevel Optimization and Optimal Control Problems with a Non-Smooth Lower Level SIAM: Journal on Optimization, 30(1), pp.290-318, 2020. (doi:10.1137/18M1225707)
•	Constantin Christof, Christof Haubner: Finite Element Error Estimates in Non-Energy Norms for the Two-Dimensional Scalar Signorini Problem Numerische Mathematik, 45, pp. 513-551, 2020. (doi:10.1007/s00211-020-01117-z)
•	Dominik Hafemeyer, Florian Mannel, Ira Neitzel, Boris Vexler: Finite element error estimates for one-dimensional elliptic optimal control by BV functions American Institute of Mathematical Science, Mathematical Control & Related Fields, V 10(2), pp. 333-363, 2020. (doi:10.3934/mcrf.2019041)
•	Dmitriy Leykekhman, Boris Vexler, Daniel Walter: Numerical Analysis of sparse initial data identification for parabolic problems Mathematical Modelling and Numerical Analysis, 54(4), pp. 1139-1180, 2020. (doi:10.1051/m2an/2019083)
•	Niklas Behringer, Dmitriy Leykekhman, Boris Vexler: Global and local pointwise error estimates for finite element approximations to the Stokes problem on convex polyhedra SIAM Journal on Numerical Analysis, 58(3), pp. 1531-1555, 2020. (doi:10.1137/19M1274456)
•	Lukas Failer, Thomas Richter: A Parallel Newton Multigrid Framework for Monolithic Fluid-Structure Interactions Journal of Scientific Computing 82(28), 2020. (doi:https://doi.org/10.1007/s10915-019-01113-y)

Appeared 2019
•	Lucas Bonifacius, Konstantin Pieper: Strong Stability of Linear Parabolic Time-Optimal Control Problems ESAIM: Control, Optimisation and Calculus of Variations, 25, 2019. (doi:10.1051/cocv/2017079)
•	Dominik Meidner, Boris Vexler: Optimal Error Estimates for Fully Discrete Galerkin Approximations of Semilinear Parabolic Equations ESAIM: Mathematical Modelling and Numerical Analysis 52(6), pp. 2307-2325, 2019. (doi:10.1051/m2an/2018040)
•	Lucas Bonifacius, Konstantin Pieper, Boris Vexler: A priori Error Estimates for Space-Time Finite Element Discretization of Parabolic Time-Optimal Control Problems SIAM Journal on Control and Optimization, 57(1) pp 129-162, 2019. (doi:10.1137/18M1166948)
•	Niklas Behringer, Dominik Meidner, Boris Vexler: Finite Element Error Estimates for Optimal Control Problems with Pointwise Tracking Pure and Applied Functional Analysis 4(2), pp. 177-204, 2019.
•	Constantin Christof, Christian Meyer: Differentiability properties of the solution operator to an elliptic variational inequality of the second kind Set-Valued and Variational Analysis, 27, pp. 469-502, 2019. (doi:10.1007/s11228-018-0495-2)
•	Johannes Pfefferer, Max Winkler: Finite element error estimates for normal derivatives on boundary concentrated meshes SIAM Journal on Numerical Analysis, 57(5), pp. 2043-2073, 2019. (doi:10.1137/18M1181341)
•	Ira Neitzel, Konstantin Pieper, Boris Vexler, Daniel Walter: A sparse control approach to optimal sensor placement in PDE-constrained parameter estimation problems Numerische Mathematik, 143(4), pp. 943-984, 2019. (doi:10.1007/s00211-019-01073-3)
•	Christian Kahle, Kei Fong Lam, Jonas Latz, Elisabeth Ullmann: Bayesian parameter identification in Cahn-Hilliard models for biological growth SIAM/ASA Journal on Uncertainty Quantification, 7(2), pp. 526-552, 2019. (doi:10.1137/18M1210034)
•	Henning Bonart, Johannes Jung, Christian Kahle, Jens-Uwe Repke: Influence of Liquid Density and Surface Tension on the Pinning of Sliding Droplets on a Triangular Microstructure Chemical Engineering & Technology, 42(7), pp. 1381-1387, 2019. (doi:10.1002/ceat.201900029)
•	Lucas Bonifacius, Konstantin Pieper, Boris Vexler: Error estimates for space-time discretization of parabolic time-optimal control problems with bang-bang controls SIAM Journal on Control and Optimization 57(3), pp. 1730-1756, 2019. (doi:10.1137/18M1213816)
•	Henning Bonart, Christian Kahle, Jens-Uwe Repke: Comparison of Energy Stable Simulation of Moving Contact Line Problems using a Thermodynamically Consistent Cahn-Hilliard Navier-Stokes Model Journal of Computational Physics, 399, 2019. (doi:10.1016/j.jcp.2019.108959)
•	Stefan Dohr, Christian Kahle, Sergejs Rogovs, Piotr Swierczynski: A FEM for an optimal control problem subject to the fractional Laplace equation CALCOLO, 56(37), 2019. (doi:10.1007/s10092-019-0334-3)
•	Constantin Christof: Sensitivity Analysis and Optimal Control of Obstacle-type Evolution Variational Inequalities SIAM Journal on Control and Optimization, 57(1), pp. 192-218, 2019. (doi:10.1137/18M1183662)
•	Sebastian Engel, Dominik Hafemeyer, Christian Münch, Daniel Schaden: An application of sparse measure valued Bayesian inversion to acoustic sound source identification Inverse Problems, 35(7), 2019. (doi:10.1088/1361-6420/ab1497)

Appeared 2018
•	Michael Hintermüller, Michael Hinze, Christian Kahle, Tobias Keil: A goal-oriented dual-weighted adaptive finite element approach for the optimal control of a nonsmooth Cahn-Hilliard-Navier-Stokes system Optimization and Engineering, 19(3), pp. 629-662, 2018. (doi:10.1007/s11081-018-9393-6)
•	Jessica Bosch, Christian Kahle, Martin Stoll: Preconditioning of a coupled Cahn-Hilliard Navier-Stokes system Communications in Computational Physics, 23(2), pp. 603-628, 2018.
•	Harald Garcke, Michael Hinze, Christian Kahle: Optimal Control of time-discrete two-phase flow driven by a diffuse-interface model ESAIM: Control, Optimisation and Calculus of Variations, 25, 2018. (doi:10.1051/cocv/2018006)
•	Behzad Azmi, Anne-Céline Boulanger, Karl Kunisch: On the semi-global Stabilizability of the Korteweg-de Vries Equation via Model Predictive Control ESAIM: Control, Optimisation and Calculus of Variations, 24(1), pp. 237-263, 2018. (doi:10.1051/cocv/2017001)
•	Philip Trautmann, Boris Vexler, Alexander Zlotnik: Finite Element Error Analysis For Measure-valued Optimal Control Problems Governed by a 1D Wave Equation with Variable Coefficients Mathematical Control and Related Fields, 8(2), pp. 411-449, 2018. (doi:10.3934/mcrf.2018017)
•	Harald Garcke, Michael Hinze, Christian Kahle, Kei Fong Lam : A phase field approach to shape optimization in Navier-Stokes flow with integral state constraint Advances in Computational Mathematics, 44(5), pp. 1345-1383, 2018. (doi:10.1007/s10444-018-9586-8)
•	Harbir Antil, Johannes Pfefferer, Sergejs Rogovs: Fractional Operators with Inhomogeneous Boundary Conditions: Analysis, Control, and Discretization Communications in Mathematical Sciences, 16(5), pp. 1395-1426, 2018. (doi:10.4310/CMS.2018.v16.n5.a11)
•	Lucas Bonifacius, Ira Neitzel: Second Order Optimality Conditions for Optimal Control of Quasilinear Parabolic Equations AIMS: Mathematical Control and Related Fields (MCRF) 8(1) 1-34, Special Issue on the occasion of Eduardo Casas' 60th birthday, 2018. (doi:10.3934/mcrf.2018001)
•	Thomas Apel, Mariano Mateos, Johannes Pfefferer, Arnd Rösch: Error estimates for Dirichlet control problems in polygonal domains: Quasi uniform meshes Mathematical Control & Related Fields, 8(1), pp. 217-245, 2018. (doi:10.3934/mcrf.2018010)
•	Dominik Meidner, Johannes Pfefferer, Klemens Schürholz, Boris Vexler: hp-Finite Elements for Fractional Diffusion SIAM Journal on Numerical Analysis 56(4), pp. 2345–2374, 2018. (doi:10.1137/17M1135517)
•	Malte Braack, Martin Quaas, Benjamin Tews, Boris Vexler: Optimization of fishing strategies in space and time as a non-convex optimal control problem Journal of Optimization Theory and Applications, 178(3), pp. 950-972, 2018. (doi:10.1007/s10957-018-1304-7)
•	Dmitriy Leykekhman, Boris Vexler: Discrete maximal parabolic regularity for Galerkin finite element methods for non-autonomous parabolic problems SIAM Journal on Numerical Analysis, 56(4), pp. 2178 – 2202, 2018. (doi:10.1137/17M114100X)
•	Christian Kahle, Kei Fong Lam: Parameter identification via optimal control for a Cahn--Hilliard-chemotaxis system with a variable mobility Applied Mathematics and Optimization, 2018. (doi:10.1007/s00245-018-9491-z)
•	Lukas Failer, Thomas Wick: Adaptive Time-Step Control for Nonlinear Fluid-Structure Interaction Journal of Computational Physics 366, pp. 448-477, 2018. (doi:10.1016/j.jcp.2018.04.021)
•	Constantin Christof, Christian Clason, Christian Meyer, Stephan Walther: Optimal Control of a Non-Smooth Semilinear Elliptic Equation Mathematical Control and Related Fields, 8(1), pp. 247-276, 2018. (doi:10.3934/mcrf.2018011)
•	Constantin Christof, Christian Meyer: A note on a priori Lp -error estimates for the obstacle problem Numerische Mathematik, 139(1), pp. 27-45, 2018. (doi:10.1007/s00211-017-0931-5)
•	Constantin Christof, Georg Müller: A Note on the Equivalence and the Boundary Behavior of a Class of Sobolev Capacities GAMM-Mitteilungen, 40(3), pp. 238-266, 2018. (doi:10.1002/gamm.201730005)
•	Constantin Christof, Gerd Wachsmuth: On the Non-Polyhedricity of Sets with Upper and Lower Bounds in Dual Spaces GAMM-Mitteilungen, 40(4), pp. 339-350, 2018. (doi:10.1002/gamm.201740005)
•	Constantin Christof, Gerd Wachsmuth: No-Gap Second-Order Conditions via a Directional Curvature Functional SIAM Journal on Optimization, 28(3), pp. 2097-2130, 2018. (doi:10.1137/17M1140418)

Appeared 2017
•	Ira Neitzel, Thomas Wick, Winnifried Wollner: An Optimal Control Problem Governed by a Regularized Phase-Field Fracture Propagation Model SIAM Journal on Control and Optimization, 55(4), pp. 2271-2288, 2017. (doi:10.1137/16M1062375)
•	Dmitriy Leykekhman, Boris Vexler: Discrete maximal parabolic regularity for Galerkin finite element methods Numerische Mathematik, 135(3), pp. 923-952, 2017. (doi:10.1007/s00211-016-0821-2)
•	Anne-Celine Boulanger, Philip Trautmann: Sparse Optimal Control of the KdV-Burgers Equation on a Bounded Domain SIAM Journal on Control and Optimization 55(6), pp. 3673-3706, 2017. (doi:10.1137/15M1020745)
•	Dmitriy Leykekhman, Boris Vexler: Global and interior pointwise best approximation results for the gradient of Galerkin solutions for parabolic problems SIAM Journal on Numerical Analysis 55(4), pp. 2025-2049, 2017. (doi:10.1137/16M1080252)
•	Christian Kahle: An L∞ bound for the Cahn-Hilliard equation with relaxed non-smooth free energy International Journal of Numerical Analysis and Modeling, 14(2), pp. 243-254, 2017.
•	Harbir Antil, Johannes Pfefferer, Mahamadi Warma: A note on semilinear fractional elliptic equation: analysis and discretization ESAIM: Mathematical Modelling and Numerical Analysis, 51(6), pp. 2049-2067, 2017. (doi:10.1051/m2an/2017023)
•	Dmitriy Leykekhman, Boris Vexler : Optimal a priori error estimates of parabolic optimal control problems with a moving point control Solvability, Regularity, Optimal Control of Boundary Value Problems for PDEs, Springer Verlag, pp. 327-356, 2017. (doi:10.1007/978-3-319-64489-9_13)
•	Thomas Apel, Johannes Pfefferer, Max Winkler: Error estimates for the postprocessing approach applied to Neumann boundary control problems in polyhedral domains IMA Journal of Numerical Analysis, 38(4) pp. 1984-2025, 2017. (doi:10.1093/imanum/drx059)
•	Thomas Apel, Serge Nicaise, Johannes Pfefferer: Adapted numerical methods for the Poisson equation with L2 boundary data in nonconvex domains SIAM Journal on Numerical Analysis, 55(4), pp. 1937-1957, 2017.
•	Constantin Christof: L∞-error estimates for the obstacle problem revisited Calcolo, 54(4), pp. 1243-1264, 2017. (doi:10.1007/s10092-017-0228-1)

Appeared 2016
•	Karl Kunisch, Philip Trautmann, Boris Vexler: Optimal control of the undamped linear wave equation with measure valued controls SIAM Journal on Control and Optimization 54(3), pp. 1212-1244, 2016. (doi:10.1137/141001366)
•	Dmitriy Leykekhman, Boris Vexler: Finite element pointwise results on convex polyhedral domains SIAM Journal on Numerical Analysis 54(2), pp. 561–587, 2016. (doi:10.1137/15M1013912)
•	Dmitriy Leykekhman, Boris Vexler: A priori error estimates for three dimensional parabolic optimal control problems with pointwise control SIAM Journal on Control and Optimization, 54(5), pp. 2403-2435, 2016. (doi:10.1137/15M1028042)
•	Lukas Failer, Dominik Meidner, Boris Vexler: Optimal Control of a Linear Unsteady Fluid-Structure Interaction Problem Journal of Optimization Theory and Applications, 170(1), pp. 1-27, 2016. (doi:10.1007/s10957-016-0930-1)
•	Dmitriy Leykekhman, Boris Vexler: Pointwise best approximation results for Galerkin finite element solutions of parabolic problems SIAM Journal on Numerical Analysis 54(3), pp. 1365-1384, 2016. (doi:10.1137/15M103412X)
•	Thomas Apel, Serge Nicaise, Johannes Pfefferer: Discretization of the Poisson equation with non-smooth data and emphasis on non-convex domains Numer Methods Partial Differential Equations 32(5), pp. 1433-1454, 2016. (doi:10.1002/num.22057)
•	Harald Garcke, Michael Hinze, Christian Kahle: A stable and linear time discretization for a thermodynamically consistent model for two-phase incompressible flow Applied Numerical Mathematics 99, pp. 151-171, 2016. (doi:10.1016/j.apnum.2015.09.002)
•	Harald Garcke, Claudia Hecht, Michael Hinze, Christian Kahle, Kei Fong Lam: Shape optimization for surface functionals in Navier-Stokes flow using a phase field approach Interfaces and Free Boundaries 18(2), pp. 219-261, 2016. (doi:10.4171/IFB/363)

Appeared 2015
•	Anne-Céline Boulanger, Philippe Moireau, Benoit Perthame, Jacques Saint-Marie: Data Assimilation for hyperbolic conservation laws. A Luenberger observer approach based on a kinetic description Communications in Mathematical Sciences 13(3), pp. 587-622, 2015. (doi:10.4310/CMS.2015.v13.n3.a1)
•	Thomas Apel, Mariano Mateos, Johannes Pfefferer, Arnd Rösch: On the regularity of the solutions of Dirichlet optimal control problems in polygonal domains SIAM Journal on Control and Optimization 53(6), pp. 3620-3641, 2015. (doi:10.1137/140994186)
•	Bernhard Kiniger: A Transformation Approach in Shape Optimization: Existence and Regularity Results Numerical Functional Analysis and Optimization, 36(12), pp. 1585-1621, 2015. (doi:10.1080/01630563.2015.1076001)
•	Dominik Meidner, Thomas Richter: A Posteriori Error Estimation for the Fractional Step Theta Discretization of the Incompressible Navier-Stokes Equations Computer Methods in Applied Mechanics and Engineering 288, pp. 45-59, 2015. (doi:10.1016/j.cma.2014.11.031)
•	Ira Neitzel, Johannes Pfefferer, Arnd Rösch: Finite element discretization of state-constrained elliptic optimal control problems with semilinear state equation SIAM Journal on Control and Optimization, 53(2), pp. 874-904, 2015. (doi:10.1137/140960645)
•	Eduardo Casas, Boris Vexler, Enrique Zuazua: Sparse initial data identification for parabolic PDE and it´s finite element approximations Mathematical Control and Related Fields 5(3), pp. 377-399, 2015. (doi:10.3934/mcrf.2015.5.377)
•	Karl Kunisch, Konstantin Pieper, Armin Rund: Time optimal control for a reaction diffusion system arising in cardiac electrophysiology - a monolithic approach ESAIM: Mathematical Modelling and Numerical Analysis 50(2), pp. 381-414, 2015. (doi:10.1051/m2an/2015048)
•	Mariano Mateos, Ira Neitzel: Dirichlet control of elliptic state constrained problems Computational Optimization and Applications 63(3), pp. 825-853, 2015. (doi:10.1007/s10589-015-9784-y)
•	Thomas Apel, Johannes Pfefferer, Max Winkler: Local Mesh Refinement for the Discretisation of Neumann Boundary Control Problems on Polyhedra Mathematical Methods in the Applied Sciences, 39(5), pp. 1206-1232, 2015. (doi:10.1002/mma.3566)
•	Klaus Krumbiegel, Johannes Pfefferer: Superconvergence for Neumann boundary control problems governed by semilinear elliptic equations Computational Optimization and Applications 61(2), pp. 373-408, 2015. (doi:10.1007/s10589-014-9718-0)
•	Thomas Apel, Johannes Pfefferer, Arnd Rösch: Finite element error estimates on the boundary with application to optimal control Mathematics of Computation 84, pp. 33-70, 2015. (doi:10.1090/S0025-5718-2014-02862-7)
•	Thomas Apel, Serge Nicaise, Johannes Pfefferer: A dual singular complement method for the numerical solution of the Poisson equation with L2 boundary data in non-convex domains Preprint arXiv: 1505.00414, 2015.
•	Harald Garcke, Claudia Hecht, Michael Hinze, Christian Kahle: Numerical approximation of phase field based shape and topology optimization for fluids SIAM Journal on Scientific Computing, 2015. (doi:10.1137/140969269)

Appeared 2014
•	Dominik Meidner, Thomas Richter: Goal-Oriented Error Estimation for the Fractional Step Theta Scheme Computational Methods in Applied Mathematics 14(2), pp. 203-220, 2014. (doi:10.1515/cmam-2014-0002)
•	Andreas Springer, Boris Vexler: Third Order Convergent Time Discretization for Parabolic Optimal Control Problems with Control Constraints Computational Optimization and Applications 57(1), pp. 205-240, 2014. (doi:10.1007/s10589-013-9580-5)
•	Pedro Merino, Ira Neitzel, Fredi Tröltzsch: An Adaptive Numerical Method for Semi-Infinite Elliptic Control Problems Based on Error Estimates Optimization Methods and Software, 30(3), pp. 492-515, 2014. (doi:10.1080/10556788.2014.932789)
•	Eduardo Casas, Mariano Mateos, Boris Vexler: New Regularity Results and Improved Error Estimates for Optimal Control Problems with State Constraints ESAIM: Control, Optimisation and Calculus of Variations 20(3), pp. 803-822, 2014. (doi:10.1051/cocv/2013084)
•	Barbara Kaltenbacher, Alana Kirchner, Boris Vexler: Goal oriented adaptivity in the IRGNM for parameter identification in PDEs II: All-at-once formulations Inverse Problems, 30(4), 045002, 2014. (doi:10.1088/0266-5611/30/4/045002)
•	Barbara Kaltenbacher, Alana Kirchner, Slobodan Veljovic: Goal oriented adaptivity in the IRGNM for parameter identification in PDEs I: Reduced formulation Inverse Problems, 30(4), 045001, 2014. (doi:10.1088/0266-5611/30/4/045001)
•	Bernhard Kiniger, Jinming Lu, Gerwin Riedl, Ewald A. Werner: Three-dimensional tool design for steady-state electrochemical machining by continuous adjoint-based shape optimization Chemical Engineering Science 106, pp. 198-210, 2014. (doi:10.1016/j.ces.2013.11.040)
•	Karl Kunisch, Konstantin Pieper, Boris Vexler: Measure valued directional sparsity for parabolic optimal control problems SIAM Journal on Control and Optimization 52(5), pp. 3078-3108, 2014. (doi:10.1137/140959055)

Appeared 2013
•	Dmitriy Leykekhman, Dominik Meidner, Boris Vexler: Optimal Error Estimates for Finite Element Discretization of Elliptic Optimal Control Problems with Finitely Many Pointwise State Constraints Computational Optimization and Applications 55(3), pp. 769-802, 2013. (doi:10.1007/s10589-013-9537-8)
•	Konstantin Pieper, Boris Vexler: A Priori Error Analysis for Discretization of Sparse Elliptic Optimal Control Problems in Measure Space SIAM Journal on Control and Optimization 51(4), pp. 2788-2808, 2013. (doi:10.1137/120889137)
•	Dmitriy Leykekhman, Boris Vexler: Optimal a Priori Error Estimates of Parabolic Optimal Control Problems with Pointwise Control SIAM Journal on Numerical Analysis 51(5), pp. 2797-2821, 2013. (doi:10.1137/120885772)
•	Sandra May, Rolf Rannacher, Boris Vexler: Error Analysis for a Finite Element Approximation of Elliptic Dirichlet Boundary Control Problems SIAM Journal on Control and Optimization 51 (3), pp. 2585-2611, 2013. (doi:10.1137/080735734)
•	Bernhard Kiniger, Boris Vexler: A Priori Error Estimates for Finite Element Discretizations of a Shape Optimization Problem ESAIM: Mathematical Modelling and Numerical Analysis 47(6), pp. 1733-1763, 2013. (doi:10.1051/m2an/2013086)
•	Thomas Richter, Andreas Springer, Boris Vexler: Efficient Numerical Realization of Discontinuous Galerkin Methods for Temporal Discretization of Parabolic Problems Numerische Mathematik 124(1), pp. 151-182, 2013. (doi:10.1007/s00211-012-0511-7)
•	Anne-Céline Boulanger, Marie-Odile Bristeau, Jacques Saint-Marie: Analytical solutions for the free surface hydrostatic Euler equations Communications in Mathematical Sciences 11(4), pp. 993-1010, 2013. (doi:10.4310/CMS.2013.v11.n4.a5)
•	Olivier Bernard, Anne-Céline Boulanger, Marie-Odile Bristeau, Jacques Saint-Marie: A 2D model for hydrodynamics and biology coupling applied to algae growth simulations ESAIM: Mathematical Modelling and Numerical Analysis 47(5), pp. 1387-1412, 2013. (doi:10.1051/m2an/2013072)
•	Michael Hintermüller, Michael Hinze,Christian Kahle: An adaptive finite element Moreau-Yosida-based solver for a coupled Cahn-Hilliard/Navier-Stokes system Journal of Computational Physics 235, pp. 810-827, 2013. (doi:10.1016/j.jcp.2012.10.010)

Appeared 2012
•	Ira Neitzel, Boris Vexler: A Priori Error Estimates for Space-Time Finite Element Discretization of Semilinear Parabolic Optimal Control Problems Numerische Mathematik 120(2), pp. 345-386, 2012. (doi:10.1007/s00211-011-0409-9)
•	Klaus Krumbiegel, Ira Neitzel, Arnd Rösch: Regularization for Semilinear Elliptic Optimal Control Problems with Pointwise State and Control Constraints Computational Optimization and Applications 52(1), pp. 181-207, 2012. (doi:10.1007/s10589-010-9357-z)
•	Thomas Apel, Johannes Pfefferer, Arnd Rösch: Finite Element Error Estimates for Neumann Boundary Control Problems on Graded Meshes Computational Optimization and Applications 52(1), pp. 3-28, 2012. (doi:10.1007/s10589-011-9427-x)

Appeared 2011
•	Alana Kirchner, Dominik Meidner, Boris Vexler: Trust Region Methods with Hierarchical Finite Element Models for PDE-Constrained Optimization Control and Cybernetics 40(4), pp. 1019-1042, 2011.
•	Dominik Meidner, Boris Vexler: A Priori Error Analysis of the Petrov-Galerkin Crank-Nicolson Scheme for Parabolic Optimal Control Problems SIAM Journal on Control and Optimization 49(5), pp. 2183-2211, 2011. (doi:10.1137/100809611)
•	Dominik Meidner, Rolf Rannacher, Boris Vexler: A Priori Error Estimates for Finite Element Discretizations of Parabolic Optimization Problems with Pointwise State Constraints in Time SIAM Journal on Control and Optimization 49(5), pp. 1961-1997, 2011. (doi:10.1137/100793888)
•	Barbara Kaltenbacher, Alana Kirchner, Boris Vexler: Adaptive Discretizations for the Choice of a Tikhonov Regularization Parameter in Nonlinear Inverse Problems Inverse Problems 27(12), 2011. (doi:10.1088/0266-5611/27/12/125008)
•	Axel Kröner, Karl Kunisch, Boris Vexler: Semismooth Newton Methods for Optimal Control of the Wave Equation with Control Constraints SIAM Journal on Control and Optimization 49(2), pp. 830-858, 2011. (doi:10.1137/090766541)
•	Thomas Apel, Olaf Benedix, Dieter Sirch, Boris Vexler: A Priori Mesh Grading for an Elliptic Problem with Dirac Right-hand Side SIAM Journal on Numerical Analysis 49(3), pp. 992-1005, 2011. (doi:10.1137/090778018)
•	Ira Neitzel, Uwe Prüfert, Thomas Slawig: A Smooth Regularization of the Projection Formula for Constrained Parabolic Optimal Control Problems Numerical Functional Analysis and Optimization 32(12), pp. 1283-1315, 2011. (doi:10.1080/01630563.2011.597915)
•	Pedro Merino, Ira Neitzel, Fredi Tröltzsch: On Linear-Quadratic Elliptic Control Problems of Semi-Infinite Type Applicable Analysis 90(6), pp. 1047-1074, 2011. (doi:10.1080/00036811.2010.489187)

Appeared 2010
•	Pedro Merino, Fredi Tröltzsch, Boris Vexler: Error Estimates for the Finite Element Approximation of a Semilinear Elliptic Control Problem with State Constraints and Finite Dimensional Control Space ESAIM: Mathematical Modelling and Numerical Analysis 44(1), pp. 167-188, 2010. (doi:10.1051/m2an/2009045)
•	Klaus Krumbiegel, Ira Neitzel, Arnd Rösch: Sufficient Optimality Conditions for the Moreau-Yosida-Type Regularization Concept Applied to Semilinear Elliptic Optimal Control Problems with Pointwise State Constraints Mathematics and its Applications - Annals of AOSR 2(2), pp. 222-246, 2010.
•	Pedro Merino, Ira Neitzel, Fredi Tröltzsch: Error Estimates for the Finite Element Discretization of Semi-infinite Elliptic Optimal Control Problems Discussiones Mathematicae. Differential Inclusions, Control and Optimization 30(2), pp. 221-236, 2010.

Appeared 2009
•	Dominik Meidner, Rolf Rannacher, Jevgeni Vihharev: Goal-Oriented Error Control of the Iterative Solution of Finite Element Equations Journal of Numerical Mathematics 17(2), pp. 143-172, 2009. (doi:10.1515/JNUM.2009.009)
•	Olaf Benedix, Boris Vexler: A Posteriori Error Estimation and Adaptivity for Elliptic Optimal Control Problems with State Constraints Computational Optimization and Applications 44(1), pp. 3-25, 2009. (doi:10.1007/s10589-008-9200-y)
•	Axel Kröner, Boris Vexler: A Priori Error Estimates for Elliptic Optimal Control Problems with Bilinear State Equation Journal of Computational and Applied Mathematics 230(2), pp. 781-802, 2009. (doi:10.1016/j.cam.2009.01.023)
•	Ira Neitzel, Fredi Tröltzsch: On Regularization Methods for the Numerical Solution of Parabolic Control Problems with Pointwise State Constraints ESAIM: Control, Optimisation and Calculus of Variations 15 (2), pp. 426-453, 2009. (doi:10.1051/cocv:2008038)
•	Ira Neitzel, Uwe Prüfert, Thomas Slawig: Strategies for Time-Dependent PDE Control with Inequality Constraints Using an Integrated Modeling and Simulation Environment Numerical Algorithms 50, pp. 241-269, 2009. (doi:10.1007/s11075-008-9225-4)

Appeared 2008
•	Dominik Meidner, Boris Vexler: A Priori Error Estimates for Space-Time Finite Element Discretization of Parabolic Optimal Control Problems. Part II: Problems with Control Constraints SIAM Journal on Control and Optimization 47(3), pp. 1301-1329, 2008. (doi:10.1137/070694028)
•	Dominik Meidner, Boris Vexler: A Priori Error Estimates for Space-Time Finite Element Discretization of Parabolic Optimal Control Problems. Part I: Problems without Control Constraints SIAM Journal on Control and Optimization 47(3), pp. 1150-1177, 2008. (doi:10.1137/070694016)
•	Samuel Amstutz, Takeo Takahashi, Boris Vexler: Topological Sensitivity Analysis for Time-Dependent Problems ESAIM: Control, Optimisation and Calculus of Variations 14(3), pp. 427-455, 2008. (doi:10.1051/cocv:2007059)
•	Michael Schmich, Boris Vexler: Adaptivity with Dynamic Meshes for Space-Time Finite Element Discretizations of Parabolic Equations SIAM Journal on Scientific Computing 30(1), pp. 369-393, 2008. (doi:10.1137/060670468)
•	Boris Vexler, Winnifried Wollner: Adaptive Finite Elements for Elliptic Optimization Problems with Control Constraints SIAM Journal on Control and Optimization 47(1), pp. 509-534, 2008. (doi:10.1137/070683416)
•	Anke Griesbaum, Barbara Kaltenbacher, Boris Vexler: Efficient Computation of the Tikhonov Regularization Parameter by Goal Oriented Adaptive Discretization Inverse Problems 24(2), 2008. (doi:10.1088/0266-5611/24/2/025025)
•	Juan Carlos de los Reyes, Christian Meyer, Boris Vexler: Finite Element Error Analysis for State-Constrained Optimal Control of the Stokes Equations Control and Cybernetics 37(2), pp. 251-284, 2008.
•	Ira Neitzel, Fredi Tröltzsch: On Convergence of Regularization Methods for Nonlinear Parabolic Optimal Control Problems with Control and State Constraints Control and Cybernetics 37(4), pp. 1013-1043, 2008.

Appeared 2007
•	Dominik Meidner, Boris Vexler: Adaptive Space-Time Finite Element Methods for Parabolic Optimization Problems SIAM Journal on Control and Optimization 46(1), pp. 116-142, 2007. (doi:10.1137/060648994)
•	Roland Becker, Dominik Meidner, Boris Vexler: Efficient Numerical Solution of Parabolic Optimization Problems by Finite Element Methods Optimization Methods and Software 22(5), pp. 813-833, 2007. (doi:10.1080/10556780701228532)
•	Boris Vexler: Finite Element Approximation of Elliptic Dirichlet Optimal Control Problems Numerical Functional Analysis and Optimization 28(7-8), pp. 957-973, 2007. (doi:10.1080/01630560701493305)
•	Roland Griesse, Boris Vexler: Numerical Sensitivity Analysis for the Quantity of Interest in PDE-constrained Optimization SIAM Journal on Scientific Computing 29(1), pp. 22-48, 2007. (doi:10.1137/050637273)
•	Roland Becker, Boris Vexler: Optimal Control of the Convection-Diffusion Equation Using Stabilized Finite Element Methods Numerische Mathematik 106(3), pp. 349-367, 2007. (doi:10.1007/s00211-007-0067-0)
•	Karl Kunisch, Boris Vexler: Optimal Vortex Reduction for Instationary Flows based on Translation Invariant Cost Functionals SIAM Journal on Control and Optimization 46(4), pp. 1368-1397, 2007. (doi:10.1137/050632774)
•	Karl Kunisch, Boris Vexler: Constrained Dirichlet Boundary Control in L2 for a Class of Evolution Equations SIAM Journal on Control and Optimization 46(5), 1726-1753, 2007. (doi:10.1137/060670110)

Appeared 2006
•	Arnd Rösch, Boris Vexler: Optimal Control of the Stokes Equations: A Priori Error Analysis for Finite Element Discretization with Postprocessing SIAM Journal on Numerical Analysis 44(5), 1903-1920, 2006. (doi:10.1137/050637364)

Appeared 2005
•	Roland Becker, Boris Vexler: Mesh Refinement and Numerical Sensitivity Analysis for Parameter Calibration of Partial Differential Equations Journal of Computational Physics 206(1), pp. 95-110, 2005. (doi:10.1016/j.jcp.2004.12.018)
•	Roland Becker, Malte Braack, Boris Vexler: Parameter Identification for Chemical Models in Combustion Problems Applied Numerical Mathematics 54(3-4), pp. 519-536, 2005. (doi:10.1016/j.apnum.2004.09.017)
•	Rolf Rannacher, Boris Vexler: A Priori Error Estimates for the Finite Element Discretization of Elliptic Parameter Identification Problems with Pointwise Measurements SIAM Journal on Control and Optimization 44(5), pp. 1844-1863, 2005. (doi:10.1137/040611100)

Appeared 2004
•	Roland Becker, Boris Vexler: A Posteriori Error Estimation for Finite Element Discretization of Parameter Identification Problems Numerische Mathematik 96(3), pp. 435-459, 2004. (doi:10.1007/s00211-003-0482-9)
•	Roland Becker, Malte Braack, Boris Vexler: Numerical Parameter Estimation for Chemical Models in Multidimensional Reactive Flows Combustion Theory and Modelling 8(4), pp. 661-682, 2004. (doi:10.1088/1364-7830/8/4/001)