Required information

Consider these specifications, "Whenever the system software is being upgraded, users cannot access the file system. If users can access the file system, then they can save new files. If users cannot save new files, then the system software is not being upgraded."

The goal of this exercise is to determine whether these specifications are consistent. To do this, we express these specifications in terms of the statements:

u$.$ "The software system is being upgraded."

a: "Users can access the file system."

s$.$ "Users can save new files."