consider this query in TRC is $\{x |$ $ x \in $ $\text{school S\}}$
Lets say this query is retrieve the names of all students of school $S$.
Consider this query $\{x |$ $\neg x \in $ $\text{school S\}}$
This query says that retrieve the names of all students in the school of entire universe except the names of student from school $S$
