“…We refer the reader to the survey papers [1,10], in which many aspects concerning the thin film equation are discussed. It should be noted that similar methods to those in [7] have been used in [9,11] to rigorously show that, in the limit of thin fluid threads, the solutions of the moving boundary-value problems for Stokes and Hele-Shaw flows converge towards the corresponding solutions (determined by the initial data) of the thin film equation (1.4), with n = 3 for Stokes and n = 1 for the Hele-Shaw flow. Compared with the thin film equation, system (1.1) is more involved because it is strongly coupled, both equations of (1.1) containing highestorder derivatives of f and g, and, furthermore, there are two sources of degeneracy, because both f and g may equal zero.…”