Distributional Matter Tensors in Relativity
  This paper uses products of distributions to obtain new junction conditions for relativistic shocks. In general, the shock is accompanied by a surface layer, and the new conditions generalize both Taub's jump conditions for shocks, and those of Israel and Kuchar for surface layers. In the non-relativistic limit, the surface layer is present only when the fluid is viscous or thermally conducting--a situation where the classical Rankine-Hugoniot conditions do not apply. Thus, our conditions properly extend all previous conditions, and provide complete Cauchy data needed to solve the full Navier-Stokes equations downstream of the shock. Since the associative law fails for our product, the residual uncertainty regarding the association of factors must be eliminated empirically. This is equivalent to fixing the correct initial_form_ of the equations (such as the ``conservation form'' in the Euler case) 
C. K. Raju