Definition: The operator NON stands for a family of 3 functions that:
1. generate a complementary negated relation from a given relation.
e.g. “Yesterday Renate did not buy a bicycle in Berlin.”
This does not exclude that she bought something else in Berlin.
or
2. build a negated modal term from a modality.
e.g. “The wing must not be damaged.”
or
3. represent the truth value “false” as a zero-place function.
e.g. here is negation of a whole situation;
“Yesterday Renate bought nothing in Berlin.”