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Re: Editorial changes in Section 2.5

From: Enrico Franconi <franconi@inf.unibz.it>
Date: Mon, 30 Jan 2006 12:51:44 +0100
Message-Id: <A71DC189-4225-46F8-94E7-1A1A18ECCCFC@inf.unibz.it>
Cc: RDF Data Access Working Group <public-rdf-dawg@w3.org>
To: Andy Seaborne <andy.seaborne@hp.com>
"""
Definition: Basic Graph Pattern equivalent
Two basic graph patterns are basic graph pattern equivalent if there  
is a bijection between the nodes of the triple patterns that maps  
blank nodes to blank nodes and maps variables, literals and IRIs to  
themselves.
"""

Mmhhh, I'm not sure it is correct :-(
You need to maintain the structure, not only the nodes (item 5.  
below)...
I still believe that either we have the real formal notion, or just  
the informal one:

option a)
"""
Two basic graph patterns BGP and BGP' are graph-equivalent if there  
is a bijection M between the sets of nodes of the two basic graph  
patterns, such that:
    1. M maps blank nodes to blank nodes.
    2. M(lit)=lit for all RDF literals lit which are nodes of BGP.
    3. M(iri)=iri for all RDF IRI references uri which are nodes of BGP.
    4. M(var)=var for all query  variables var which are nodes of BGP.
    5. The triple ( s, p, o ) is in BGP if and only if the triple ( M 
(s), M(p), M(o) ) is in BGP'.
"""

option b)
"""
Two basic graph patterns are graph-equivalent if they are the same up  
to bnode renaming.
"""


--e.

Received on Monday, 30 January 2006 11:51:56 GMT

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