Potential theory has its roots in the physical sciences and continues to nd
application in diverse areas including electrostatics and elasticity. From a mathematical point of view, the study of Laplace's equation has profoundly
in
uenced the theory of partial dierential equations and the development
of functional analysis. Together with the wave operator and the diusion
operator, its study and application continue to dominate many areas of
mathematics, physics, and engineering. Scattering of electromagnetic or
acoustic waves is of widespread interest, because of the enormous number
of technological applications developed in the last century, from imaging
to telecommunications and radio astronomy