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Re: types of OWL

From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Date: Sat, 03 Apr 2004 13:39:48 +0100
Message-ID: <406EB094.8050208@hplb.hpl.hp.com>
To: Yuzhong Qu <yzqu@seu.edu.cn>
Cc: Dan Brickley <danbri@w3.org>, www-rdf-logic@w3.org


I think with Qu's, Evan's and Dan's replies, I stand corrected.

Jeremy


Yuzhong Qu wrote:

> As to the reasoning complexity, 
> 
> OWL DL has a difficult entailment problem, as inference in SHOIN(D) is of worst-case nondeterministic exponential time (NExpTime) complexity.
> 
> Inference in SHIF(D) is of worst-case deterministic exponential time (ExpTime) complexity, and OWL Lite has the same complexity.
> 
> Reference
> [1] Ian Horrocks, Peter F. Patel-Schneider, and Frank van Harmelen. From SHIQ and RDF to OWL: The making of a web ontology language. Journal of Web Semantics, 1(1):7-26, 2003
> [2] Stephan Tobies. Complexity Results and Practical Algorithms for Logics in Knowledge Representation. PhD thesis, LuFG Theoretical Computer Science, RWTHAachen,Germany, 2001.
> 
> 
> Yuzhong Qu 
> 
> P.S. The complexity may be the most important element.
> 
> ----- Original Message ----- 
> From: "Dan Brickley" <danbri@w3.org>
> To: "ror" <galvinr@tcd.ie>
> Cc: <www-rdf-logic@w3.org>
> Sent: Friday, April 02, 2004 8:59 PM
> Subject: Re: types of OWL
> 
> 
> 
>>* Dan Brickley <danbri@w3.org> [2004-04-02 07:53-0500]
>>
>>>* ror <galvinr@tcd.ie> [2004-04-02 13:16+0100]
>>>
>>>>Hello,
>>>>
>>>>I've been trying to find the underlying differences between the different
>>>>types of OWL languages i.e: OWL DL, OWL Lite and OWL full.
>>>>
>>>>Are all of these languages forms of Description Logic? As far as I can gather
>>>>OWL Lite is less expressive to suit users who want to incorporate semantics
>>>>into their applications without the over complexity of OWL DL and full.
>>>>
>>>>Does OWL lite use different forms of axioms than full or DL
>>>>
>>>>If someone could set me straight on the differences I would be very grateful!
>>>
>>>Here's a sketch.
>>>
>>>"Full" is the full OWL language, an RDF-based language that extends RDFS with 
>>>constructs useful for describing the terms used in Ontologies. "OWL DL"  
>>>is a profile of that language created with special care to make it easy 
>>>to work with in the Description Logic tradition. "OWL Lite" goes further in 
>>>that direction, by ommiting some constructs known to be tough to work with
>>>using DL techniques.
>>
>>Re-reading your question, I guess you were looking for more details. I
>>think the basic situation is that things from DL that aren't in Lite
>>were taken out on the basis of their being known to be difficult to 
>>implement. My understanding is that someone should be well on their way
>>to implementing OWL Lite by studying the published DL literature, whereas
>>complete reasoning with DL is more researchy...
>>
>>Dan
>>
>>
>>
Received on Saturday, 3 April 2004 07:41:06 GMT

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