[Pellet-users] problem for description logics!

[Evren Sirin]

On 10/29/07 10:44 PM, Jun Fang wrote:
> Dear all,
>
> As we know, in DL,
> C satisfiable with K mean there exists at least one model of K such 
> that the interpretation of C is nonempty.
> C unsatisfiable with K mean there doesn't exist any model of K which 
> can interpret C.
>
> if K is set to {A subclass of B}, and  concept is set to C
> C should be satisfiable with K
>
> but in pellet, i found C is unsatisfiable with K,  why?

This is an API design decision for Pellet. The function 
KnowledgeBase.isSatisfiable function will always return false for any 
concept that is not defined in the KB although semantically there is no 
constraint. This has proved to be more useful in practice because asking 
for undefined concepts generally indicate an error on the calling function.

If you want to distinguish between logically inconsistent concepts and 
undefined concepts there is a configuration option you can change. If 
the option named SILENT_UNDEFINED_ENTITY_HANDLING is set to false then 
isSatisfiable function will throw an UndefinedEntityException that you 
can catch and handle accordingly.

Cheers,
Evren
>
> Thanks for any comments!
>
> -- 
> Best Regards!
>
> Jun Fang - PhD candidate,
> Control & Networks Institute,
> College of Automation,
> Northwestern Polytechnical University,
> Xi'an, Shaanxi Province, China
> E-mail:leon.essence at gmail.com <mailto:leon.essence at gmail.com>
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