Re: Detecting cycles in OWL

Thanks Pascal, saves lot's of time if this is not possible by normal OWL 
DL means. That PDF looks like worth atleast trying to understand.

Followup question to forum: how does one continue usually when reasoning 
capabilities hit the wall? SWRL and SPARQL queries are the next steps?

On 24/04/2020 17.01, Pascal Hitzler wrote:
> You probably find more about these matter than you care about here: 
> But let me break down your example.
> you want to say something like the following:
> A(x) AND p1(x,y) AND C(y) AND p2(y,z) AND B(z) AND p4(w,z) AND D(w) 
> AND p3(x,w) --> E(x)
> And essentially you want to know whether there is anything in the 
> class E.
> With the rolification technique in the above referenced paper, yo 
> would come up with the following to express the axiom:
> A equiv exists R_A.Self
> B equiv exist R_B.Self
> C equiv exists R_C.Self
> D equiv exists R_D.Self
> R_A o p1 o R_C o p2 o R_B o p4- o R_D o p3- subPropertyOf R
> exists R.Self subClassOf E
> Now, these six axioms *syntactically* translated into first-order 
> predicate logic do the trick.
> HOWEVER, you would use Self with a non-simple role, which is not 
> allowed under OWL DL.
> So the short answer is: it doesn't look like it's possible.
> The above paper discusses a construct called nominal schemas, which is 
> (very complex) syntactic sugar on top of OWL, an which allows you to 
> express the rule above, provided that the variable x can bind only to 
> individuals actually occurring in the knowledge base.
> Best Regards,
> Pascal.

Lingsoft - 30 years of Leading Language Management

Speech Applications - Language Management - Translation - Reader's and Writer's Tools - Text Tools - E-books and M-books

Mikael Pesonen
System Engineer

Tel. +358 2 279 3300

Time zone: GMT+2

Helsinki Office
Eteläranta 10
FI-00130 Helsinki

Turku Office
Kauppiaskatu 5 A
FI-20100 Turku

Received on Friday, 24 April 2020 14:11:09 UTC