%X Every population game defines a vector field on the set of strategy distributions X. The projection dynamic maps each population game to a new vector field: namely, the one closest to the payoff vector field among those that never point outward from X. We investigate the geometric underpinnings of the projection dynamic, describe its basic game-theoretic properties, and establish a number of close connections between the projection dynamic and the replicator dynamic. %D 2007 %I ESRC Centre for Economic Learning and Social Evolution %T The projection dynamic, the replicator dynamic and the geometry of population games %L discovery14428 %S ELSE Working Papers %N 271 %A E. Dokumaci %A R. Lahkar %A W.H. Sandholm %C London, UK