Spacetime from locality of interactions in deformations of special relativity: the example of $\kappa$-Poincar\'e Hopf algebra

A new proposal for the notion of spacetime in a relativistic generalization of special relativity based on a modification of the composition law of momenta is presented. Locality of interactions is the principle which defines the spacetime structure for a system of particles. The formulation based on $\kappa$-Poincar'e Hopf algebra is shown to be contained in this framework as a particular example.