In the context of firm location analysis,
may describe the spatio-temporal heterogeneity which
occurs because exogenous factors lead firms to locate (or cease to operate) in certain specific
geographical zones and in certain periods of time. For instance, firms may group together in some
areas and period of times in order to exploit favorable local conditions, such as the presence of
useful infrastructures, the proximity to the communication routes, or more favorable local taxation
systems.