Conformal Carroll groups and BMS symmetry
  The Bondi-Metzner-Sachs (BMS) group is shown to be the conformal extension of Levy-Leblond's "Carroll" group. Further extension to the Newman-Unti (NU) group is also discussed in the Carroll framework. 
C. Duval, G. W. Gibbons, P. A. Horvathy
gr-qc hep-th math-ph math.MP