RELATIVISTIC AND NEWTONIAN KAPPA-SPACE-TIMES

The deformations of the Galilei algebra and their associated noncommutative Newtonian space-times are investigated. This is done by analyzing the possible nonrelativistic limits of an eleven generator (pseudo)extended kappa-Poincare algebra (P) over tilde(kappa) and their implications for the existence of a first-order differential calculus. The additional one-form needed to achieve a consistent calculus on kappa-Minkowski space is shown to be related to the additional central generator entering in the (P) over tilde(kappa) Hopf algebra. In the process, deformations of the extended Galilei and Galilei algebras are introduced which have, respectively, a cocycle and a bicrossproduct structure. (C) 1995 American Institute of Physics.