Junction Conditions, Resolution of Singularities and Nonlinear Equations of Physics
arXiv:math/0611445
Abstract
For large classes of systems of polynomial nonlinear PDEs necessary and sufficient conditions are given for the existence of solutions which are discontinuous across hyper-surfaces. These PDEs contain the Navier-Stokes equations, as well as those of General Relativity and Magneto-Hydrodynamics.