The numerical approximation of an inverse problem subject to the convection–diffusion equation when diffusion dominates is studied. We derive Carleman estimates that are on a form suitable for use in numerical analysis and with explicit dependence on the Peclet number. A stabilized finite element method is then proposed and analysed. An upper bound on the condition number is first derived. Combining the stability estimates on the continuous problem with the numerical stability of the method, we then obtain error estimates in local H1- or L2-norms that are optimal with respect to the approximation order, the problem’s stability and perturbations in data. The convergence order is the same for both norms, but the H1-estimate requires an additional divergence assumption for theconvective field. The theory is illustrated in some computational examples

## Abstract

## Authors

**Erik Burman
**Department of Mathematics, University College London, Gower Street, London UK, WC1E 6BT

**Mihai Nechita
**Department of Mathematics, University College London, Gower Street, London UK, WC1E 6BT

** Lauri Oksanen
**Department of Mathematics, University College London, Gower Street, London UK, WC1E 6BT

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## Paper coordinates

E. Burman, M. Nechita, L. Oksanen, *A stabilized finite element method for inverse problems subject to the convection-diffusion equation. I: diffusion-dominated regime, *arXiv:1811.00431

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