Group contractions and its consequences upon representations of   different spatial symmetry groups
  We investigate the group contraction method for various space-time groups, including SO(3)->E_2, SO(3,1)->G_3, SO(5-h,h)->P(3,1) (h=1 or 2), and its consequences for representations of these groups. Following strictly quantum mechanical procedures we specifically pay attention in the asymptotic limiting procedure employed in the contraction G -> G', not only to the respective algebras but to their representations spaces spanned by the eigenvectors of the Cartan subalgebra and the eigenvalues labelling these representation spaces. Where appropriate a physical interpretation is given to the contraction prodecure. 
Mauricio Ayala (Universidad de los Andes, Bogota - Colombia), Richard   Haase (Universidad Nacional, Bogota - Colombia)