Covariant representations of the de Sitter isometry group
  We show that the induced representations of the de Sitter isometry group proposed many years ago by Nachtmann are equivalent to those derived from our general theory of external symmetry. These methods complete each other leading to a coherent theory of covariant fields with spin on the de Sitter spacetime. Some technical details of these representations are presented here for the first time. 
Ion I. Cotaescu
gr-qc hep-th math-ph math.MP