On a group-theoretical approach to the curl operator
  We utilize group-theoretical methods to develop a matrix representation of differential operators that act on tensors of any rank. In particular, we concentrate on the matrix formulation of the curl operator. A self-adjoint matrix of the curl operator is constructed and its action is extended to a complex plane. This scheme allows us to obtain properties, similar to those of the traditional curl operator. 
J. Ramos, M. de Montigny, F.C. Khanna
math-ph math.MP