Polyharmonic Hardy Spaces on the Complexified Annulus and Error   Estimates of Cubature Formulas
  The present paper has a twofold contribution: first, we introduce a new concept of Hardy spaces on a multidimensional complexified annular domain which is closely related to the annulus of the Klein-Dirac quadric important in Conformal Quantum Field Theory. Secondly, for functions in these Hardy spaces, we provide error estimate for the polyharmonic Gau\ss -Jacobi cubature formulas, which have been introduced in previous papers. 
Ognyan Kounchev, Hermann Render
math.NA math.CV