This property associates an instance of E4 Period with the real (phenomenal) 4 dimensional point set (volume) in spacetime that it has occupied. The associated instance of E92 Spacetime Volume includes the trajectories of the participating physical things during their participation in the instance of E4 Period, the open spaces via which they have interacted and the spaces by which they had the potential to interact during that period or event in the way defined by the type of the respective period or event, such as the air in a meeting room transferring the voices. Another example are the areas controlled by some military power. In general, instances of E4 Period have fuzzy boundaries in spacetime.
