Multi-dimensional Weiss operators
  We present a solution of the Weiss operator family generalized for the case of $\mathbb{R}^{d}$ and formulate a d-dimensional analogue of the Weiss Theorem. Most importantly, the generalization of the Weiss Theorem allows us to find a sub-set of null class functions for a partial differential equation with the generalized Weiss operators. We illustrate the significance of our approach through several examples of both linear and non-linear partial differential equations. 
S. Borisenok, M. H. Erkut, Y. Polatoglu, M. Demirer
math.AP