Résumé
We study the relaxation process in a simple glass former-the Kob-Andersen lattice gas model. We show that, for this model, structural relaxation is due to slow percolation of regions of cooperatively moving particles, which leads to heterogeneous dynamics of the system. We find that the size distribution of these regions is given by a power law and that their formation is encoded in the initial structure of the particles, with the memory of initial configuration increasingly retained with increasing density.