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Re: Lean vs. Not Lean

From: Jeremy Carroll <jjc@hpl.hp.com>
Date: Mon, 21 Nov 2005 10:07:25 +0000
Message-ID: <43819C5D.5090201@hpl.hp.com>
To: Ryan Hayes <ryguillian@gmail.com>
CC: www-rdf-interest@w3.org

Ryan Hayes wrote:
> A concrete example of the difference between lean versus non lean
> graphs would be helpful; the example in RDF Semantics[1] is confusing.
> What is the difference between lean and non lean graphs?
> 
> Thanks in advance,
> 
> Ryan
> 
> [1] http://www.w3.org/TR/2004/REC-rdf-mt-20040210/
> 
> 

redundancy

e.g.

<eg:a> <eg:p> _:a .
<eg:a> <eg:p> _:b .

is not lean, because the second triple adds no new information.

It is entailed by its subgraph

<eg:a> <eg:p> _:a .


Also

<eg:a> <eg:p> _:a .
<eg:a> <eg:p> _:b .
_:a <eg:q> _:c.

Is not lean, entailed by
<eg:a> <eg:p> _:a .
_:a <eg:q> _:c.


Similarly
<eg:a> <eg:p> <eg:c> .
<eg:a> <eg:p> _:b .

is not lean, entailed by
<eg:a> <eg:p> <eg:c> .


Whereas
<eg:a> <eg:p> _:a .
<eg:a> <eg:p> _:b .
_:a <eg:q> _:c.
_:b <eg:r> _:d .

is lean, since none of its proper subgraphs entail it.

Jeremy
Received on Monday, 21 November 2005 10:08:20 GMT

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