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Re: Terminology for RDF Statement Sets

From: Brian McBride <bwm@hplb.hpl.hp.com>
Date: Sun, 15 Apr 2001 22:57:40 +0100
Message-ID: <3ADA1954.7E57B66@hplb.hpl.hp.com>
To: Sandro Hawke <sandro@w3.org>
CC: www-rdf-interest@w3.org
Sandro,

A reference to this thread has been placed in the RDF issues list under:

  http://www.w3.org/2000/03/rdf-tracking/#rdf-terminologicus

Brian


Sandro Hawke wrote:
> 
> There's a technique in object-oriented design where you listen to all
> the different words people are using and then turn those words into
> class names.  In the RDF community, there seem to be a small number of
> concepts for which an large number of terms are used.  I'm going to
> try to list the ones I've heard, suggest what I think they mean, and
> generally suggest this be on the RDF Issues List.
> 
> As background, there are also various other terms in use for "RDF
> statement".  I've heard (and used) "statement", "assertion", "triple",
> "3-tuple", "tuple", "sentence", and "property statement", at least.
> But I think "RDF Statement" is okay for the formal documents and for
> this message.
> 
> The area I'm concerned about is sets (in the mathematic, set theory
> sense) of RDF statements.  Let me list some of the terms I've heard,
> and see if I can organize them.
> 
> (set itself)
>   statement set
>   graph
>   subgraph
>   model
>   theory   (a set of theorems; rdf statements as simple theorems)
>   infoset   (an RDF infoset, not an XML infoset)
>   dataset
>   corpus (a body of knowledge; term I coined some years back)
>   world
>   universe
>   description
>   semantic content  ("for is in the semantic content of document bar")
>   knowledge base
> 
> (set storage)
>   triple store
>   repository
>   database  (or set itself; ambiguous)
> 
> (set encoding)
>   context (in n3)
>   logical formula
>   document   ("does RDF document foo include RDF statement bar?")
>   text     (like document)
> 
> (set source)
>   attribution
>   provenance
> 
> (The term "model" deserves a special disambiguation: "*The* RDF Model"
> is the architecture, technique, or method of building things we use in
> the RDF community.  "*An* RDF Model" is a representation of some
> knowledge as a collection of RDF sentences (made according to *the* RDF
> Model).  I would suggest "architecture" for the former sense, and the
> latter sense is the subject of this message.)
> 
>  * "RDF" or "RDF Statement" Specializations
> 
> Some of these terms are well understood in some field, and we just
> want a specialization.  We can prepend "RDF" to be make our usage
> precise if the context does not do so.  Terms like "RDF statement set"
> or "RDF infoset" or "RDF statement repository" work this way.
> 
> Many of these terms are defined in the appropriate sense only in some
> fairly narrow field or context.  For example, you need just the right
> setting to have the phrase "an RDF theory" understood to mean a set of
> RDF sentences.
> 
>  * Confusing Information with its Identification
> 
> We sometimes conflate a set with the attributes of the set we use to
> identify it, such as where it is stored and where we got it from.
> Contrast terms for the information itself ("dataset"), the place it
> exists ("repository"), the thing representing or encoding it
> ("document"), or the source of the information ("provenance").
> 
> Quite a bit could be said about this kind of confusion.  In common
> usage, the term "database" is used for both a collection of data and
> for a database management system (a running process, or the software).
> Think of all the ways one might answer "What database did you use?" in
> different situations.
> 
> This distinction is intentionally ignored in most programming systems.
> In C, an "int" is a C object (an area of memory) which represents an
> integer.  It is not actually an integer itself, of course.  In C this
> is rarely a problem.
> 
> For us, though, it may be more pernitious.  In set theory, sets are
> immutable.  But we programmers are used to Set.add(element) and
> Set.remove(element) because we conflate mathematical sets with the
> data structures which can be used to store information about set
> membership.  To me, every term on the above list could be used in a
> mutable sense, because I have the programmer's habit of naming data
> structures (mutable or not) after the objects about which they store
> data.  So what term can I use to unambiguously denote the
> mathematically pure, immutable kind of set of RDF statements?
> 
>     -- sandro
Received on Sunday, 15 April 2001 17:57:24 GMT

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