What is the overlap of epidemic time and space? What is the scope of epidemic time and space overlap

Recently, the epidemic prevention measures in Beijing have been strengthened. On November 1st, a regulation was proposed to temporarily suspend entry into Beijing due to the overlap of time and space. However, paying attention to the professional terminology of the epidemic, such as the overlap of time and space, has been difficult for many people. What does the coincidence of epidemic time and space mean? What scope does this epidemic overlap in time and space?

Epidemic space-time overlap refers to the places where confirmed cases of the COVID-19 epidemic or asymptomatic infected people have visited, where the tracks overlap, and when the tracks overlap, they are generally designated as close contacts. What scope does the overlap of epidemic time and space include?

Currently, the overlap of epidemic time and space generally refers to personnel in the same community, the same supermarket, and the same station or airport. For example, if a confirmed case takes a high-speed train or train, but you and he are in the same carriage or on the same train, it will also be considered as a coincidence of epidemic time and space.