“…These equations constrain the velocity and pressure to a surface and, at least for stationary surfaces, enforce the velocity to be tangential to the surface, which leads to a tide coupling with geometric properties of the surface and new physical phenomena. Despite the apparent practical relevance, there has been only recently a strongly growing mathematical interest in modeling of surface fluids, e.g., [4,42,26,28,29,35,40,55,57,68,54] and their numerical simulation, e.g., [42,5,55,39,53,58,17,43,9,46,7,45,68,30,54,69]. Surface (Navier-)Stokes equations are also studied as an interesting mathematical problem on its own, e.g., [15,67,66,3,34,2].…”