A posteriori error estimates for the Electric Field Integral Equation on   polyhedra
  We present a residual-based a posteriori error estimate for the Electric Field Integral Equation (EFIE) on a bounded polyhedron. The EFIE is a variational equation formulated in a negative order Sobolev space on the surface of the polyhedron. We express the estimate in terms of square-integrable and thus computable quantities and derive global lower and upper bounds (up to oscillation terms). 
Ricardo H. Nochetto and Benjamin Stamm
math.NA