A NONLINEAR BACKWARD PARABOLIC PROBLEM: REGULARIZATION BY QUASI-REVERSIBILITY AND ERROR ESTIMATES
Abstract
In this paper, we consider an inverse time problem for a nonlinear parabolic equation in the form ut + Au(t) = f(t, u(t)), u(T) = φ, where A is a positive self-adjoint unbounded operator and f is a Lipschitz function. As known, it is ill-posed. Using a quasi-reversibility method, we shall construct regularization solutions depended on a small parameter ϵ. We show that the regularized problem is well-posed and that their solution uϵ(t) converges on [0, T] to the exact solution u(t). This paper extends the work by Dinh Nho Hao et al. [8] to nonlinear ill-posed problems. Some numerical tests illustrate that the proposed method is feasible and effective.