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Property Paths Cardinality

From: Steve Harris <steve.harris@garlik.com>
Date: Fri, 28 May 2010 08:10:07 +0100
Message-Id: <BAC340AB-B608-4F23-B907-516D2F6D772C@garlik.com>
To: SPARQL Working Group <public-rdf-dawg@w3.org>
Overall seems pretty sensible, but there's one proposal that I'm not clear on:

"PROPOSED: The cardinality of solutions to fixed-length paths
is the same as the cardinality of solutions to the path expanded into
triple patterns (with all variables projected); the cardinality of
solutions to variable-length paths is the cardinality of solutions
via paths that do not repeat nodes; the cardinality of solutions to
paths combining fixed and variable length (elt{n,} ) is a combination
of the fixed definition plus the variable definition for paths longer than the fixed length."

I've read the minutes, but it's a little hard to interpret this proposal without known-good examples.

I'm guessing this means that ?x :p/:q* ?y is variable length path and so that part of the solution is effectively distinct? Another interpretation is that the :p sub-path is fixed length, so only the :q part of the path is distinct.

- Steve 
Received on Friday, 28 May 2010 07:09:48 UTC

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