[Attempto] AceWiki - how to get explanation of red?

[Tobias Kuhn]

Hi Alex,

To come back to this earlier message:

Basically, I agree that just rejecting statements containing transitivity axioms is not at all a 
satisfying solution. However, I would like to keep the "showcase" AceWiki application as simple as 
possible and I don't see a simple and clean way how to deal with those axioms.

I have some vague plans to make AceWiki more customizable so that the subset of OWL to be used for 
reasoning can be changed without changing the source code. At the moment, one would have to change 
the source code. (If you cannot wait, I can show you which part of source code has to be changed.)


Tobias



Alex Shkotin wrote:
> Hi,
>  
> If Pellet returns error (well, without explanation;) but only in this 
> case it is better to say user a truth:
> your axiom makes ontology undecidable. try re-formulate or ask support...
>  
> actually this kind of situation in practice should be very interesting 
> and if user insist then it is time for brain storm;)
> Alex
> 
>  
> 2009/7/1 Tobias Kuhn <t.kuhn at gmx.ch <mailto:t.kuhn at gmx.ch>>
> 
>     Hi,
> 
>     Right, Pellet can handle TransitiveObjectProperty as long as the
>     restrictions are not violated. By the way: my link was outdated and
>     they are now called "Global Restrictions on Axioms":
> 
>      http://www.w3.org/TR/owl2-syntax/#Global_Restrictions_on_Axioms_in_OWL_2_DL
> 
>     However, once the restrictions are violated, Pellet stops running
>     properly and returns error messages. What should AceWiki do now? How
>     should it inform the users about the problem?
> 
>     In my view, these global restrictions are too complicated to be
>     explained to an average web user.
> 
> 
>     Tobias
> 
> 
>     Alex Shkotin wrote:
> 
>         Hi Tobias,
>          may be it is better to check "Nonstructural Restrictions on
>         Axioms", and disallow TransitiveObjectProperty only in a case of
>         violation.
>         As this kind of reasoning (trans-closure) is one of DL's strong
>         feature.
>         Anyway why not give it to Pellet. I doubt that Pellet ignores
>         TransitiveObjectProperty. Does it?
>          Alex
> 
> 
>         2009/7/1 Tobias Kuhn <t.kuhn at gmx.ch <mailto:t.kuhn at gmx.ch>
>         <mailto:t.kuhn at gmx.ch <mailto:t.kuhn at gmx.ch>>>
> 
> 
>            Hi,
> 
>            Blue bullets mean "is used by the reasoner". Red bullets mean "is
>            not used by the reasoner". The latter is the case for all
>         statements
>            that cannot be translated into OWL or that would use the OWL
>            constructs TransitiveObjectProperty or
>         SubObjectPropertyChain. The
>            problem with these two axiom types is that statements using
>         them can
>            violate the "Nonstructural Restrictions on Axioms":
> 
>            
>         http://www.w3.org/TR/2008/WD-owl2-syntax-20080411/#Nonstructural_Restrictions_on_Axioms
> 
>            Since I don't know how to handle these restrictions in a
>            collaborative environment like a wiki, I simply disallow the
>         axiom
>            types that are involved.
> 
>            Thus, the reason why you don't get an answer for questions like
>            "Which continent contains Oslo?" is that the statement "If X is
>            located in Y and Y is located in Z then X is located in Z." is
>            ignored by the reasoner.
> 
>            If you have an idea how TransitiveObjectProperty and
>            SubObjectPropertyChain could be supported in a simple way without
>            the danger to violate these nonstructural restrictions, let
>         me know!
> 
> 
>            Tobias
> 
> 
> 
>            George Herson wrote:
> 
>                I added some sentences to the current Oslo page at
>                http://attempto.ifi.uzh.ch/webapps/acewikigeo/ and it
>         seems to
>                me that
> 
> 
>                 Edit...
>                Add Sentence...
>                Add Comment...
>                Delete
>                Details
>                Logic
>                   Oslo  is  located in  which  continent ?    (no answer
>         found)
>                should find an answer since we have
> 
> 
>                 Edit...
>                Add Sentence...
>                Add Comment...
>                Delete
>                Details
>                Logic
>                   Norway  is  located in  which  continent ?    -
>          Europe and rule
> 
> 
> 
>                 Edit...
>                Add Sentence...
>                Add Comment...
>                Delete
>                Details
>                Logic
>                   If  X  is  located in  Y  and  Y  is  located in  Z
>          then  X
>                 is  located in  Z .    So sorry, maybe an expert will be
>         more
>                helpful.
> 
>                George
>                ________________________________
>                From: Alex Shkotin <alex.shkotin at gmail.com
>         <mailto:alex.shkotin at gmail.com>
>                <mailto:alex.shkotin at gmail.com
>         <mailto:alex.shkotin at gmail.com>>>
>                To: George Herson <gherson at snet.net
>         <mailto:gherson at snet.net> <mailto:gherson at snet.net
>         <mailto:gherson at snet.net>>>
>                Cc: attempto at lists.ifi.uzh.ch
>         <mailto:attempto at lists.ifi.uzh.ch>
>         <mailto:attempto at lists.ifi.uzh.ch
>         <mailto:attempto at lists.ifi.uzh.ch>>
> 
>                Sent: Tuesday, June 30, 2009 2:38:44 PM
>                Subject: Re: [Attempto] AceWiki - how to get explanation
>         of red?
> 
> 
>                yes, I need to say vise versa but have a look at
>                http://clip2net.com/clip/m3050/1246386847-clip-8kb.png
>                 sorry, but after "Which continent is Oslo" there is no
>                continuation:(
> 
> 
>                2009/6/30 George Herson <gherson at snet.net
>         <mailto:gherson at snet.net> <mailto:gherson at snet.net
>         <mailto:gherson at snet.net>>>
> 
> 
> 
>                Re: "Which continent is located in Oslo?", try variations on
>                "Which continent is Oslo located-in?": Oslo is a city, much
>                smaller than a continent.
> 
> 
>                George
>                ________________________________
>                From: Alex Shkotin <alex.shkotin at gmail.com
>         <mailto:alex.shkotin at gmail.com>
>                <mailto:alex.shkotin at gmail.com
>         <mailto:alex.shkotin at gmail.com>>>
>                To: George Herson <gherson at snet.net
>         <mailto:gherson at snet.net> <mailto:gherson at snet.net
>         <mailto:gherson at snet.net>>>
>                Cc: attempto at lists.ifi.uzh.ch
>         <mailto:attempto at lists.ifi.uzh.ch>
>         <mailto:attempto at lists.ifi.uzh.ch
>         <mailto:attempto at lists.ifi.uzh.ch>>
> 
>                Sent: Tuesday, June 30, 2009 2:20:11 PM
>                Subject: Re: [Attempto] AceWiki - how to get explanation
>         of red?
> 
> 
> 
>                Hi George,
>                then why my question (after rule) is without answer?
> 
> 
>                2009/6/30 George Herson <gherson at snet.net
>         <mailto:gherson at snet.net> <mailto:gherson at snet.net
>         <mailto:gherson at snet.net>>>
> 
> 
> 
>                Hi Alex,
> 
>                My guess is that AceWiki bullets are red for rules and
>         blue for
>                facts.
> 
>                George
>                ________________________________
>                From: Alex Shkotin <alex.shkotin at gmail.com
>         <mailto:alex.shkotin at gmail.com>
>                <mailto:alex.shkotin at gmail.com
>         <mailto:alex.shkotin at gmail.com>>>
>                To: attempto at lists.ifi.uzh.ch
>         <mailto:attempto at lists.ifi.uzh.ch>
>         <mailto:attempto at lists.ifi.uzh.ch
>         <mailto:attempto at lists.ifi.uzh.ch>>
> 
>                Sent: Tuesday, June 30, 2009 12:55:34 PM
>                Subject: [Attempto] AceWiki - how to get explanation of red?
> 
> 
> 
>                Hi,
>                have a look at a picture.
>                how can I tell that red sentence is definition?
>                how can I get an explanation  - why the sentence is red?
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