Can the intersection of time and space get out of the market?

Close contacts refer to people who have close contact with suspected cases and confirmed cases but have not taken effective protection 2 days before symptoms appear or 2 days before asymptomatic infected persons are sampled. The concepts of the two are completely different, but both have certain risks. Both of them need to do a good job of personal protection and report in time.

Space-time intersection means that my phone number is detected by the epidemic prevention system, and the associated phone number of the confirmed patient stays in the same space-time grid (800 m *800 m range) for more than 14 minutes, and any number stays for more than 30 hours in the recent 14 days, then the found number is a space-time adjoint number, and I will also be marked as "space-time intersection".