Variational and Topological Methods: Theory, Applications, Numerical Simulations, and Open Problems. Electron. J. Diff. Eqns., Conference 21 (2014), pp. 173-181. Title: Tikhonov regularization using Sobolev metrics Authors: Parimah Kazemi (Ripon College, Ripon, WI, USA) Robert J. Renka (Univ. of North Texas, Denton, TX, USA) Abstract: Given an ill-posed linear operator equation Au=f in a Hilbert space, we formulate a variational problem using Tikhonov regularization with a Sobolev norm of u, and we treat the variational problem by a Sobolev gradient flow. We show that the gradient system has a unique global solution for which the asymptotic limit exists with convergence in the strong sense using the Sobolev norm, and that the variational problem therefore has a unique global solution. We present results of numerical experiments that demonstrates the benefits of using a Sobolev norm for the regularizing term. Published February 10, 2014. Math Subject Classifications: 47A52, 65D25, 65F22. Key Words: Gradient system; Ill-posed problem; least squares; Sobolev gradient; Tikhonov regularization.