[Pellet-users] Concept consistency

[Bijan Parsia]

On Wed, May 30, 2007 5:42 am, sjtirtha <sjtirtha at gmail.com> said:

> I'm checking now concept consistency to an OWL file over DIG interface. I
> get always java error OutOfMemory on the Pellet DIG Server.
> I extended Pellet DIG Server with -Xmx1000m. Now Pellet DIG server is just
> checking the concept consistency and but it doesn't stop checking.

This can happen.

> Can Pellet check a huge/complex OWL file ?

Yes, but not *all* such. No reasoner can. The worst case complexity of OWLDL is NEXPTIME, and even beyond that there are standard families of cases where the current optimizations do not work well. Inverses are standardly an issue, esp. in combination with transitivity and (deep) role heirarchies. Progress continues.

> What do I need to consider in OWL
> modeling, if I use Pellet reasoner.

(Taowei? Would you put the profiling paper on the mindswap site?)

There are many things and many are not specific to Pellet. One thing that can be a gotcha is that the mere presence of an inverse, even if not uses, triggers a completion strategy that can be frustrated pretty easily.

In protege4 it's pretty easy to switch between Pellet and FaCT++, which is worth doing. There are definitely cases for each where they are better.

Cheers,
Bijan.