RE: [ACTION-18] use case on !ASK in FILTERS to emulate negation

> WHERE { ?x foaf:givenName  ?name .
>         !EXISTS { ?x dc:date ?date }
>       }

Maybe '!' should get 'NOT' synonym, for readability?

In addition, I still think that EXISTS without FILTER around are a bit
confusing, esp. if the next clause is OPTIONAL {...}.

Best Regards,

Ivan.