[Attempto] Extra variables and individuals created in OWL+SWRL

[Kaarel Kaljurand]

Hi,

On Wed, Sep 25, 2013 at 10:38 PM, Jean-Marc Vanel
<jeanmarc.vanel at gmail.com> wrote:
> Here is an example :
>
> If an n:appartment A v:has-surface S and P = ( S * 7000 ) then A v:has-price
> P .
> A1 is an n:appartment . A1 v:has-surface 100 .
>
>
> And how it is translated with  -solo owlfsspp :
>
>    DLSafeRule(
>       Body(
>          ClassAtom(
>             :appartment
>             Variable(<urn:swrl#x1>)
>          )
>          ObjectPropertyAtom(
>             :has-surface
>             Variable(<urn:swrl#x1>)
>             Variable(<urn:swrl#x2>)
>          )
>          BuiltInAtom(<swrlb:equal>
>             Variable(<urn:swrl#x4>)
>             Variable(<urn:swrl#xg1>)
>          )
>          BuiltInAtom(<swrlb:multiply>
>             Variable(<urn:swrl#xg1>)
>             Variable(<urn:swrl#x2>)
>             "7000"^^<http://www.w3.org/2001/XMLSchema#integer>
>          )
>       )
>       Head(
>          ObjectPropertyAtom(
>             :has-price
>             Variable(<urn:swrl#x1>)
>             Variable(<urn:swrl#x4>)
>          )
>       )
>    )
>    DataPropertyAssertion(
>       :has-surface
>       _:199541176426535230
>       "100"^^<http://www.w3.org/2001/XMLSchema#integer>
>    )
>    SameIndividual(
>       _:199541176426535230
>       _:977449132216104540
>    )
>    ClassAssertion(
>       :appartment
>       _:977449132216104540
>    )
>    ClassAssertion(
>       owl:Thing
>       _:199541176426535230
>    )
>
>
> It's not wrong, but variable xg1 and individual _:977449132216104540 could
> be eliminated and replaced by x4 and _:199541176426535230  respectively .

Yes, I agree. I think the problem is that it's too difficult to do the
elimination during the construction of these formulas, i.e. it has to
be done in post-processing. (E.g. maybe the rule engine could rewrite
these rules into a more compact form while loading them.)

How do these extra equality statements affect you? Do they show up in
a confusing way in a visualization or in reasoning results?

Best,
Kaarel