Poincaré representations of the massless class (Q1317473)

Representations of the Poincaré group (or inhomogeneous Lorentz group) have been completely classified by Wigner. They include zero-mass representations induced by matrix representations of the little group \(E(2)\), the Euclidean group in two dimensions. Also their relation to the description of massless particles such as the photon is well understood. Neither from the mathematical nor from the physical point of view, one can hardly add new facets to our present understanding, and the article under review is no exception to this rule. In fact, the reader has to work hard before he realizes that many results, he is already familiar with, are once more reproduced in a very obscure language and notation. In his own words the author wishes ``to illustrate the difference between these (i.e., representations) and those of other cases, like compact semisimple Lie groups''.