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Re: meaning of a function name

From: Pat Hayes <phayes@ihmc.us>
Date: Thu, 13 Apr 2006 16:36:09 -0700
Message-Id: <p06230900c0648fd0f48d@[]>
To: "Seaborne, Andy" <andy.seaborne@hp.com>
Cc: Eric Prud'hommeaux <eric@w3.org>, public-rdf-dawg@w3.org

>Eric Prud'hommeaux wrote:
>>By the current spec, I don't see any reason to believe that the
>>following my:funcs have anything to do with each other:
>>   ASK WHERE { ?x my:func ?y	      FILTER (my:func(?x) || 
>>	      my:func(?x ?y)) }
>>Just thought I'd mention that.
>In ARQ, my:func(?x) and my:func(?x ?y) dispatch to the same code 
>implementation.  Functions are polyadic, like varargs.
>If predicate my:func is different from function my:func, then 
>shouldn't they be different URIs as they are different concepts?

Well, I can answer that from the Common Logic point of view. No. One 
can use the same name for a class/predicate/relation/function because 
these can all be the same entity. They differ only in the arity, and 
there is no logical reason why one entity cannot have many arities. 
The Common Logic semantics is based on this idea, and RDF uses the 
same basic structure, which is why it is fine to use the same URI for 
a class and an individual and a property in OWL-Full. We have now an 
extended logic called IKL which also allows the same name to be used 
for a proposition as well. The basic rule is that if the syntax is 
rich enough to clearly distinguish the different 'uses' of a name, 
there is no harm in making these all denote the same entity.


>	Andy

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Received on Thursday, 13 April 2006 23:36:25 UTC

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