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Re: incompleteness in RDFS closure rules

From: Jos De_Roo <jos.deroo@agfa.com>
Date: Tue, 10 Jun 2003 20:10:31 +0200
To: pfps@research.bell-labs.com
Cc: gk@ninebynine.org, "Jos De_Roo" <jos.deroo@agfa.com>, phayes@ihmc.us, www-rdf-comments@w3.org, www-rdf-comments-request@w3.org
Message-ID: <OF9B8ED2EB.0B21A5E2-ONC1256D41.0062FCAF-C1256D41.0063D71F@agfa.be>



rdfs:subPropertyOf rdfs:range rdfs:Resource .

and

{: rdfs:fyi :rdfs12b. ?Q rdfs:range ?Y. ?P root:range ?X.
    ?P rdfs:subPropertyOf ?Q} => {?X rdfs:subClassOf ?Y}.

and

rdfs:subClassOf rdfs:domain rdfs:Class; rdfs:range rdfs:Class;
    root:domain rdfs:Class; root:range rdfs:Class.
rdfs:subPropertyOf rdfs:domain rdf:Property; rdfs:range rdf:Property;
    root:domain rdf:Property; root:range rdf:Property.
rdf:type rdfs:domain rdfs:Resource; rdfs:range rdfs:Class;
    root:domain rdfs:Resource.

do *not* RDFS entail

rdfs:Resource rdfs:subClassOf rdf:Property .

at least not in our implementation
(the root: is there to not have such an entailment)

Do you have a proof?


--
Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/


                                                                                                                          
                    "Peter F.                                                                                             
                    Patel-Schneider"            To:     phayes@ihmc.us                                                    
                    <pfps@research.bell-l       cc:     www-rdf-comments@w3.org, Jos                                      
                    abs.com>                     De_Roo/AMDUS/MOR/Agfa-NV/BE/BAYER@AGFA, gk@ninebynine.org                
                    Sent by:                    Subject:     Re: incompleteness in RDFS closure rules                     
                    www-rdf-comments-requ                                                                                 
                    est@w3.org                                                                                            
                                                                                                                          
                                                                                                                          
                    2003-06-10 04:55 PM                                                                                   
                                                                                                                          
                                                                                                                          





From: pat hayes <phayes@ihmc.us>
Subject: Re: incompleteness in RDFS closure rules
Date: Mon, 9 Jun 2003 13:39:52 -0500

> >        rdfs:subClassOf rdfs:subPropertyOf xxx .
> >        xxx rdfs:domain yyy .
> >
> >RDFS-entails
> >
> >        rdfs:Class rdfs:subClassOf yyy .
> >
> >but this does not come out of the RDFS closure rules.
> >
> >
> >
> >        rdfs:subClassOf rdfs:subPropertyOf xxx .
> >        xxx rdfs:range yyy .
> >
> >RDFS-entails
> >
> >        rdfs:Class rdfs:subClassOf yyy .
> >
> >but this does not come out of the RDFS closure rules.
> >
> >
> >
> >        rdfs:subPropertyOf rdfs:subPropertyOf xxx .
> >        xxx rdfs:domain yyy .
> >
> >RDFS-entails
> >
> >        rdf:Property rdfs:subClassOf yyy .
> >
> >but this does not come out of the RDFS closure rules.
> >
> >
> >
> >        rdfs:subPropertyOf rdfs:subPropertyOf xxx .
> >        xxx rdfs:range yyy .
> >
> >RDFS-entails
> >
> >        rdf:Property rdfs:subClassOf yyy .
> >
> >but this does not come out of the RDFS closure rules.
>
>
> Yes, you are perfectly correct. The rule rdfs12 has been generalized
> to include these cases, as follows:
>
> rdfs12a
>
> ppp rdfs:subPropertyOf zzz .
> ppp rdfs:domain xxx .
> zzz rdfs:domain yyy .
> |-
> xxx rdfs:subClassOf yyy .
>
> rdfs12b
>
> ppp rdfs:subPropertyOf zzz .
> ppp rdfs:range xxx .
> zzz rdfs:range yyy .
> |-
> xxx rdfs:subClassOf yyy .
>
> where in 12a, ppp is one of rdf:type, rdfs:subPropertyOf,
> rdfs:subClassOf, and in 12b only the last two are allowed (because an
> empty class need not be in the range of a superproperty of rdf:type).
> Including rdf:type in the 12a case covers the inference noticed
> earlier by Herman, though the rationale is somewhat different.  These
> rules are not valid more generally because of the inclusive nature of
> domain and range.
>
> BTW, the URI of the current editors draft has changed somewhat: these
> changes are now visible at
>
> http://www.ihmc.us/users/phayes/RDF_Semantics_Edit_nT.html
>
> Thanks for noticing this.
>
> Pat

I do not believe that these rules are valid.

For example, if I say

           rdfs:subPropertyOf rdfs:range rdfs:Resource .

which seems like a benign thing to say,  then I get the conclusion

           rdfs:Resource rdfs:subClassOf rdf:Property .

from rule rdfs12b.

peter
Received on Tuesday, 10 June 2003 14:39:22 GMT

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