Quantum Deformations of Space-Time Symmetries with Mass-Like Deformation   Parameter
  The difficulties with the measurability of classical space-time distances are considered. We outline the framework of quantum deformations of D=4 space-time symmetries with dimensionfull deformation parameter, and present some recent results. 
Jerzy Lukierski (Institute for Theoretical Physics, University of   Wroclaw, Poland)