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Re: Detecting cycles in OWL

From: Hans <hanscools@breitband.ch>
Date: Wed, 29 Apr 2020 02:59:18 +0200
To: semantic-web@w3.org
Message-ID: <c65ed699-4d3b-b548-ebe7-f4419443c811@breitband.ch>
Hi Holger,

I tend to disagree.
In my experience SPARQL is less powerful than N3-rule-based machine 
reasoning (also depending on the reasoner of course :).
Every query is a kind of 'dead end rule', whereas N3-rules can pass the 
conclusion to other rules during a same reasoning session.
A handy combination of forward and backward rules is possible.
To try to make out of SPARQL a full-blown rule system is not that 
senseful, because it is not designed for that purpose IMHO.
A strong real world use case for N3-rule-based machine reasoning is 
temporal reasoning, implying e.g. unification of different calendars 
(Gregorian, Julian, proleptic Julian and other, with all the quirks) 
with usage of Julian Day Number, AFAIK beyond the capability of SPARQL.
This case uses e.g. a cascade of backward rules triggered from within 
other rules.
It is at the end comparing apples with lemons I think.

Kind regards,
Hans

On 29.04.20 01:53, Holger Knublauch wrote:
> On 28/04/2020 20:32, Mikael Pesonen wrote:
>
>> Thanks!
>>
>> It seems that OWL reasoning has quite limited real world use: 
>> checking consistency of model and data, and deducting new facts for 
>> search etc.
>
> The lack of expressiveness of OWL has long been a problem for us and 
> many (if not most) of our customers. Even if you can express something 
> in OWL, it often becomes convoluted and non-intuitive. With SPARQL 
> (CONSTRUCT/INSERT) you can do so much more, including the use cases 
> that OWL was supposed to solve. SPIN and later SHACL were partially 
> created to declaratively link SPARQL queries with the domain ontologies.
>
> On N3 rules (mentioned in this thread), I wonder whether this 
> shouldn't simply reuse SPARQL, esp for the built-ins. Why reinvent the 
> wheel?
>
> Holger
>
>
>
Received on Wednesday, 29 April 2020 00:59:33 UTC

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