Definition: A collection of compound propositions is called consistent if there is an assignment of truth values to the propositional variables that makes each of the compound propositions true.
Consistency:
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.
Translate to symbolic compound propositions
Look for some truth assignment to the propositional variables for which all the compound propositions output \(T\)