Re: Detecting cycles in OWL

Hi William,

Regarding Enrico’s point: since N3 rules are seen as logical implications, one can reason over them, e.g., use them as part of logical conditions, or even infer new implications during reasoning.

I understand that N3 rules allow existential in the head, and recursive rules (i.e., arbitrary TGDs).
But please tell me whether my understanding is true or if there is some restriction on this.
This makes entailment in the language undecidable. Also the chase would be non-terminating.

On the open world topic, N3 features scoped negation as failure (SNAF) which allows checking whether a document / formula holds or allows deriving a given fact at a given point in time. While N3 implements the open world assumption, it allows for a monotonic negation as failure - “closing” the world to an extent that is often useful in practice.

That's interesting. I suspect that you have carefully chosen a restriction when a (sort of) minimal model exists.
Am I right? If yes, then this is basically "closed world".
But, again, tell me whether I;m wrong.

BTW: is there a spec with a logic-based semantics?

cheers
--e.