Recovery of harmonic functions in planar domains from partial boundary data respecting internal values
Résumé
We consider partially overdetermined boundary-value problem for Laplace PDE in a planar simply
connected domain with Lipschitz boundary ∂Ω. Assuming Dirichlet and Neumann data available on Γ ⊂ ∂Ω
to be real-valued functions in W 1/2,2 (Γ) and L 2 (Γ) classes, respectively, we develop a non-iterative method for
solving this ill-posed Cauchy problem choosing L 2 bound of the solution on ∂Ω \ Γ as a regularizing parame-
ter. The present complex-analytic approach also naturally allows imposing additional pointwise constraints
on the solution which, on practical side, can help incorporating outlying boundary measurements without
changing the boundary into a less regular one.