# Definition: Graph Pattern Matching

From: Dan Connolly <connolly@w3.org>
Date: Tue, 24 Aug 2004 11:58:00 -0500
To: RDF Data Access Working Group <public-rdf-dawg@w3.org>
Message-Id: <1093366680.2934.109.camel@dirk>
```
I see some nice work on the core terms in the spec in
sections 2.2 and 2.3
http://www.w3.org/2001/sw/DataAccess/rq23/#GraphPatterns

I think getting those terms and definitions established
will speed things up considerably.

Some reaction to \$Revision: 1.39 \$ of \$Date: 2004/08/24 13:35:32 \$

|let V be the set of variables
|let B be the set of bNodes

I consider bNodes to be variables, so I'd rather:

let V be the set of universal variables
let B be the set of existential variables

since RDF mt "effectively treats all blank nodes as having the same
meaning as existentially quantified variables in the RDF graph in which
they occur"

|let A be U union L union V union B

http://www.earlham.edu/~peters/courses/logsys/glossary.htm#t
so I'd use T there.

Now we have a conflict with tradition here...

|let L be the set of all literals
|let T be the set of triple patterns := A x A x A

Traditionally, a literal is something like P(x)...
"These formulas are basically sets of clauses each of which is a
disjunction of literals."
-- http://mathworld.wolfram.com/ResolutionPrinciple.html

Our "triple patterns" function much like literals. Hmm...

I don't think I can parse the "Definition: Binding" section.

I'm inclinded to break out my larch tools to review this
stuff.
http://www.w3.org/XML/9711theory/
http://www.w3.org/XML/9711theory/RDFAbSyn.lsl

--
Dan Connolly, W3C http://www.w3.org/People/Connolly/
```
Received on Tuesday, 24 August 2004 16:57:40 UTC

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