“…For nearly flat interfaces, the linearization of the Muskat problem has the same symbol as the Peskin problem considered here, and one expects similar local well-posedness and stability results so long as condition jX j > 0 holds, see, for example, [1,7,9,10,13,40]. In the simplest setup in two dimensions, the Muskat problem features two fluids in porous media whose dynamics are governed by Darcy's law.…”