Diffraction from conormal singularities
  In this paper we show that for metrics with conormal singularities that correspond to class C^{1,\alpha} with \alpha>0, the reflected wave is more regular than the incident wave in a Sobolev sense. This is helpful in the analysis of the multiple scattering series since higher order terms can be effectively `peeled off'. 
Maarten de Hoop, Gunther Uhlmann and Andr\'as Vasy
math.AP