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RE: Potential text for time-permitting features in F&R

From: Seaborne, Andy <andy.seaborne@hp.com>
Date: Thu, 25 Jun 2009 13:23:06 +0000
To: SPARQL Working Group <public-rdf-dawg@w3.org>
Message-ID: <B6CF1054FDC8B845BF93A6645D19BEA3646DA26E2B@GVW1118EXC.americas.hpqcorp.net>
The text for "time-permitting" features (inc Birte's suggestion) is good for me for FPWD.

	Andy

> -----Original Message-----
> From: public-rdf-dawg-request@w3.org [mailto:public-rdf-dawg-
> request@w3.org] On Behalf Of Lee Feigenbaum
> Sent: 25 June 2009 13:36
> To: Birte Glimm
> Cc: SPARQL Working Group
> Subject: Re: Potential text for time-permitting features in F&R
> 
> Birte, thanks. Sounds good to me.
> 
> Lee
> 
> Birte Glimm wrote:
> > Lee,
> > thanks for the work. I would suggest to rephrase OWL dialects into
> > profiles because that is the official name used in the OWL 2 spec (I
> > guess that is what you mean by dialects) and I would like to mention
> > direct semantics here because the RDF semantics of OWL does not really
> > need a different entailment regime as I understand it, e.g.:
> >
> > [...] Time-permitting, the SPARQL WG will use the existing framework
> > to define the semantics of SPARQL queries for one or more of these
> > entailment frameworks:
> > + OWL 2 with Direct Semantics including OWL 2 profiles
> > + RDF Schema
> > + RIF rule sets
> >
> > Birte
> >
> > 2009/6/25 Lee Feigenbaum <lee@thefigtrees.net>:
> >> This is to discharge my action at
> >> http://www.w3.org/2009/sparql/track/actions/49

> >>
> >> The goal here is to have enough text that explains what the time
> permitting
> >> features are in a way that:
> >>
> >> 1) is comprehensive enough to help us build out phase II charter
> >> 2) will be re-usable / extendable in future versions of the F&R
> document
> >>
> >> To this end, I've tried to do a "Motivation" and brief "Description"
> for
> >> each.
> >>
> >> Please comment on this, _especially_ if you are not comfortable with
> any of
> >> this for the FPWD. We are _not_ going to spend time on this specific
> text on
> >> Tuesday before deciding to publish a first public working draft unless
> there
> >> are concerns that we have not managed to work out between now and then
> on
> >> the mailing list.
> >>
> >> Kjetil or Alex, can you please work this into the editor's draft?
> >>
> >> Also - please note that we may need to refine the description of common
> >> functions that is a time-permitting function before publishing the
> phase ii
> >> charter, as per ISSUE-2
> (http://www.w3.org/2009/sparql/tracker/issues/2). We
> >> can do this following publication of FPWD of F&R.
> >>
> >>
> >> ~~BGP extensions for entailment regimes~~
> >>
> >> -Motivation-
> >>
> >> Many software systems that support entailment regimes such as OWL
> dialects
> >> and RDF Schema extend the semantics of SPARQL Basic Graph Pattern
> matching
> >> to apply to entailments other than simple entailment. The formal
> semantics
> >> of these SPARQL/Query extensions are not standardized, and query
> writers
> >> cannot currently be guaranteed interoperable behavior when working with
> >> multiple query engines that extend SPARQL with the same entailment
> regime..
> >>
> >> -Description-
> >>
> >> SPARQL/Query 1.0 defines a mechanism to adapt SPARQL to entailment
> regimes
> >> beyond simple entailment by providing necessary conditions on re-
> defining
> >> the meaning of SPARQL Basic Graph Pattern matching. Time-permitting,
> the
> >> SPARQL WG will use the existing framework to define the semantics of
> SPARQL
> >> queries for one or more of these entailment frameworks:
> >>  + OWL dialects, including OWL DL
> >>  + RDF Schema
> >>  + RIF rule sets
> >>
> >>
> >> ~~Property paths~~
> >>
> >> -Motivation-
> >>
> >> Many classes of query over RDF graphs require searching data structures
> that
> >> are hierarchical and involve arbitrary-length paths through the graphs.
> >> Examples include:
> >>
> >>  * Retrieving all the elements of an RDF collection (structured as a
> linked
> >> list)
> >>  * Retrieve all of the names of people linked to me transitively via
> the
> >> ex:mother and ex:father relationships (i.e. all my known ancestors)
> >>  * What are all of the direct and indirect superclasses of a given
> >> owl:Class?
> >>
> >> -Description-
> >>
> >> SPARQL/Query 1.0 can express queries over fixed-length paths within RDF
> >> graphs. SPARQL/Query 1.0 can also express queries over arbitrary but
> >> bounded-length paths via repeated UNION constructs. SPARQL/Query 1.0
> cannot
> >> express queries that require traversing hierarchical structures via
> >> unbounded, arbitrary-length paths.
> >>
> >> Time-permitting, the SPARQL Working Group will define the syntax and
> >> semantics of property paths, a mechanism for expressing arbitrary-
> length
> >> paths of predicates within SPARQL triple patterns.
> >>
> >>
> >> ~~Basic Federated Query~~
> >>
> >> -Motivation-
> >>
> >> SPARQL is a concise query language to retrieve and join information
> from
> >> multiple RDF graphs via a single query. In many cases, the different
> RDF
> >> graphs are stored behind distinct SPARQL endpoints.
> >>
> >> -Description-
> >>
> >> Federated query is the ability to take a query and provide solutions
> based
> >> on information from many different sources. It is a hard problem in its
> most
> >> general form and is the subject of continuing (and continuous)
> research. A
> >> building block is the ability to have one query be able to issue a
> query on
> >> another SPARQL endpoint during query execution.
> >>
> >> Time-permitting, the SPARQL Working Group will define the syntax and
> >> semantics for handling a basic class of federated queries in which the
> >> SPARQL endpoints to use in executing portions of the query are
> explicitly
> >> given by the query author.
> >>
> >>
> >> ~~Commonly Used SPARQL Functions~~
> >>
> >> -Motivation-
> >>
> >> Many SPARQL implementations support functions beyond those required by
> the
> >> SPARQL/Query 1.0 specification. There is little to no interoperability
> >> between the names and semantics of these functions for common tasks
> such as
> >> string manipulation.
> >>
> >> -Description-
> >>
> >> Time-permitting, the SPARQL WG will define URIs and semantics for a set
> of
> >> functions commonly supported by existing SPARQL implementations.
> >>
> >> See Working Group issue: ISSUE-2 -
> >> http://www.w3.org/2009/sparql/tracker/issues/2

> >>
> >>
> >> ~~Query language syntax~~
> >>
> >> -Motivation-
> >>
> >> Certain limitations of the SPARQL/Query 1.0 language syntax cause
> >> unnecessary barriers for learning and using SPARQL.
> >>
> >> -Description-
> >>
> >> Time-permitting, the SPARQL Working Group will consider extending
> >> SPARQL/Query's syntax to include:
> >>  + Commas between variables and expressions within a SELECT list
> >>  + IN and BETWEEN operators to abbreviate disjunction and comparisons
> within
> >> FILTER expressions
> >>
> >>
> >> Lee
> >>
> >>
> >
> >
> >

Received on Thursday, 25 June 2009 13:24:22 GMT

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