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Re: Agenda SPARQL TC 2009-01-05

From: Birte Glimm <birte.glimm@comlab.ox.ac.uk>
Date: Tue, 5 Jan 2010 14:14:02 +0000
Message-ID: <492f2b0b1001050614n1c833271j6a3b238a93ffc932@mail.gmail.com>
To: Axel Polleres <axel.polleres@deri.org>
Cc: Andy Seaborne <andy.seaborne@talis.com>, SPARQL Working Group <public-rdf-dawg@w3.org>
The current definition says:
A Pattern Instance Mapping, P, is the combination of an RDF instance
mapping, σ, and solution mapping, μ. P(x) = μ(σ(x))

below the definition there the new sentence:
For a BGP 'x', P(x) denotes the result of replacing blank nodes b in x
for which σ is defined with σ(b) and all variables v in x for which μ
is defined with μ(v).

I suggest to put that sentence into the definition and relate it to
P(x) = μ(σ(x)). For example:
A Pattern Instance Mapping, P, is the combination of an RDF instance
mapping, σ, and solution mapping, μ. For a BGP x, P(x) denotes the
result of replacing each blank node b in x for which σ is defined with
σ(b) and each variable v in x for which μ is defined with μ(v), also
denoted as P(x) = μ(σ(x)).

Basically, my goal is to make this definition clearer. I think the
definition should say what x is since it is not a defined term like
RDF-T for example. I also think the definition should say what it
means to apply a solution mapping or an RDF instance mapping to a BGP.
These are mappings from variables/bnodes to terms. It is never defined
what the functions to with BGPs. They don't map BGPs to terms. Here it
is assumed that they replace
variables/bnodes with the corresponding mappings. That has to be said
IMO. It can all be guessed, but it is a definition and it is an
important definition. I do not suggest to change anything in the
meaning. For me that still counts as errata because the definition
just did not mention what it should have mentioned.

Anyway, I just wanted the spec to be clear, but if there are
objections, I will not spend any more time on this issue.

Birte

2010/1/4 Axel Polleres <axel.polleres@deri.org>:
> Hi Birte,
>
>> Query 1.1 uses the Query 1.0 definition and adds a sentence below to
>> clarify this, but I would prefer to actually extend the definition
>> accordingly if the WG is not opposed to that. IMO, the definition
>> leaves a lot for readers to figure out themselves and it is quite an
>> essential definition. Such a change would not change the meaning of
>> the definition, but extend it so that it is clear what is meant.
>
> Do you have a concrete proposal for improval to extend the definition?
> I'd assume if so, we can discuss it, although probably there is not
> enough  time left to agree and include it in this round, so I'd prefer to
> postpone this issue to after the next WD round.
>
> best,
> Axel
>
> On 4 Jan 2010, at 15:00, Birte Glimm wrote:
>
>> Axel,
>> if there is some time in tomorrow's telecon, I would like to discuss
>> whether it is possible to clarify the definition of Pattern Instance
>> Mapping in Query 1.1.
>>
>> The Query 1.0 definition says:
>> A Pattern Instance Mapping, P, is the combination of an RDF instance
>> mapping, σ, and solution mapping, μ. P(x) = μ(σ(x))
>>
>> The problem is that it is never said what x is and readers have to
>> guess that it is a BGP. Even if they guess that x is a BGP, then it is
>> still the case that sigma and mu are only defined for blank nodes and
>> variables as input, so readers again have to guess that in this case
>> it is meant that the blank nodes and variables in the BGP x are
>> replaced with the values given by mu and sigma.
>>
>> Query 1.1 uses the Query 1.0 definition and adds a sentence below to
>> clarify this, but I would prefer to actually extend the definition
>> accordingly if the WG is not opposed to that. IMO, the definition
>> leaves a lot for readers to figure out themselves and it is quite an
>> essential definition. Such a change would not change the meaning of
>> the definition, but extend it so that it is clear what is meant.
>
> Do you have a concrete proposal to extend the definition?
>
>> Birte
>>
>>
>> 2010/1/4 Axel Polleres <axel.polleres@deri.org>:
>> > Dear all,
>> >
>> > first of all, Happy 2010 and looking fwd to welcome you to our first TC this year!
>> > On Tuesday, we obviously want to check the status of the reviews and go through them as far
>> > as there are any critical comments. We should also check the schedule in case there are reviews
>> > missing still, since we want to make a decision to publish (based on reviews & subsequent
>> > updates made by editors) in two weeks at the latest.
>> >
>> > In case we still have time left with all that on Tuesday (given the speed we rushed through all
>> > docs in the last TC before christmas, you never know), I'd like to have a look over the
>> > update ISSUEs mentioned in Paul's and Andy's mails [1,2].
>> >
>> > 1. http://lists.w3.org/Archives/Public/public-rdf-dawg/2009OctDec/0628.html
>> > 2. http://lists.w3.org/Archives/Public/public-rdf-dawg/2009OctDec/0674.html),
>> >
>> > The agenda can be found as usual at: http://www.w3.org/2009/sparql/wiki/Agenda-2010-01-05
>> > Will try to complete links to the reviews sent so far before the TC...
>> >
>> > best,
>> > Axel
>> >
>> > ============================
>> > Call in details
>> >
>> > When joining please don't identify yourself verbally; instead, identify yourself to Zakim on IRC
>> >
>> >        • Date of Call: Tuesday January 05, 2010
>> >        • Time of Call: 15:00 UK, 10:00 (East US)
>> >        • Dial-In #: +1.617.761.6200 (Cambridge, MA)
>> >        • Dial-In #: +33.4.89.06.34.99 (Nice, France)
>> >        • Dial-In #: +44.117.370.6152 (Bristol, UK)
>> >        • Participant Access Code: 77277# (SPARQ)
>> >        • IRC Channel: irc.w3.org port 6665 channel #sparql ([irc:irc.w3.org:6665/sparql])
>> >        • Web-based IRC (member-only): http://www.w3.org/2001/01/cgi-irc (Firefox IRC addon: chatzilla)
>> >        • Duration: 60 minutes
>> >        • Chair: Axel Polleres
>> >        • Scribe: Olivier Corby (Scribe List)
>> >        • Link to Agenda: http://www.w3.org/2009/sparql/wiki/Agenda-2010-01-05
>> >
>> > [edit] Agenda
>> >
>> >        • Admin
>> >                • PROPOSED: Approve minutes at http://www.w3.org/2009/sparql/meeting/2009-12-22
>> >                • Next meeting: 2010-01-12 @ 15:00 UK / 10:00 EST (scribe: Alex Passant)
>> >        • Comment handling - see http://www.w3.org/2009/sparql/wiki/Comments
>> >        • Liaisons - Anything to report?
>> >                • RIF WG (Axel)
>> >                • RDB2RDF WG (Orri)
>> >                • eGov (SteveH)
>> >        • Document Reviews and schedule for publication:
>> >                • http://www.w3.org/2009/sparql/docs/query-1.1/
>> >                • http://www.w3.org/2009/sparql/docs/update-1.1/
>> >                • http://www.w3.org/2009/sparql/docs/protocol-1.1/
>> >                • http://www.w3.org/2009/sparql/docs/service-description-1.1/
>> >                • http://www.w3.org/2009/sparql/docs/http-rdf-update/
>> >                • http://www.w3.org/2009/sparql/docs/property-paths/Overview.xml
>> >                • http://www.w3.org/2009/sparql/docs/entailment/xmlspec.xml
>> >        • Time allowed: Update ISSUEs, Can we close some? see Paul's and Andy's mails.
>> > [edit] Regrets
>> >
>> >        • Lee Feigenbaum
>> >
>> >
>> >
>>
>>
>>
>> --
>> Dr. Birte Glimm, Room 306
>> Computing Laboratory
>> Parks Road
>> Oxford
>> OX1 3QD
>> United Kingdom
>> +44 (0)1865 283529
>>
>
>



-- 
Dr. Birte Glimm, Room 306
Computing Laboratory
Parks Road
Oxford
OX1 3QD
United Kingdom
+44 (0)1865 283529
Received on Tuesday, 5 January 2010 14:14:41 GMT

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