The minimizing total variation flow with measure initial conditions

In this paper we obtain existence and uniqueness of solutions for the Cauchy problem for the minimizing total variation flow when the initial condition is a Radon measure in R-N. We study limit solutions obtained by weakly approximating the initial measure mu by functions in L-1(R-N). We are able to characterize limit solutions when the initial condition mu = h + mu(s) where h epsilon L-1(R-N) boolean AND L-infinity (R-N), and mu(s) = alphaH(k) right angle S, alpha greater than or equal to 0, k is an integer and S is a k-dimensional manifold with bounded curvatures. In case k < N - 1 we prove that the singular part of the solution does not move, it remains equal to A. for all t greater than or equal to 0. In particular, u(t) = delta(0) when u(0) = delta(0). In case k = N - 1 we prove that the singular part of the limit solution is (1 - 2/alpha t)(+)mu(s) and we also characterize its absolutely continuous part. This explicit behaviour permits to characterize limit solutions. We also give an entropy condition characterization of the solution which is more satisfactory when k < N - 1. Finally, we describe some distributional solutions which do not have the behaviour characteristic of limit solutions.