Relative localization of point particle interactions
  We review the main concepts of the recently introduced principle of relative locality and investigate some aspects of classical interactions between point particles from this new perspective. We start with a physical motivation and basic mathematical description of relative locality and review the treatment of a system of classical point particles in this framework. We then examine one of the unsolved problems of this picture, the apparent ambiguities in the definition of momentum constraints caused by a non-commutative and/or non-associative momentum addition rule. The gamma ray burst experiment is used as an illustration. Finally, we use the formalism of relative locality to reinterpret the well-known multiple point particle system coupled to 2+1 Einstein gravity, analyzing the geometry of its phase space and once again referring to the gamma ray burst problem as an example. 
Jos\'e Ricardo Oliveira
gr-qc