RIF Telecon 4 Sept 07

4 Sep 2007


See also: IRC log



csma, Dave_Reynolds, AllenGinsberg, josb, LeoraMorgenstern, Harold, +43.512.507.9aaaa, Stella_Mitchell, ChrisW, barry_b, PaulVincent, DougL, Sandro, Gary_Hallmark, DavidHirtle, luis_polo, Hassan_Ait-Kaci, Michael_Kifer, DaveReynolds


IgorMozetic, AxelPolleres (unstable connection, unlikely that I can dial in), PaulaLaviniaPatranjan (unstable connection, unlikely that I can dial in)


Christian de Sainte-Marie


Allen Ginsberg




<ChrisW> Scribe: Allen Ginsberg

<ChrisW> scribenick: AllenGinsberg

<csma> Chair: Christian de Sainte Marie

<csma> Scribe: Allen Ginsberg

<csma> scribenick: AllenGinsberg


csma: action review

chrisW: action 334 closed, 335 done

minutes accepted for aug 28 telecon


csma: no action to review

<PaulVincent> OMG PRR: no news


csma: everyone please fill out f2f survey

<sandro> F2F7 Register/Regrets

chrisW: no unpdates on f2f

csma: first draft agenda by end of next week
... skipping UCR item because Axel not here
... any volunteer to review another one?

<Harold> As I mentioned, Axel and Paula told me they have only a shakey connection from the Reasoning Web Summer School in Dresden.

chrisW: any volunteers for next week?

csma: Axel should do it next week

<ChrisW> http://www.w3.org/2005/rules/wg/wiki/D._Evaluation%3A_Use_Cases

chrisW: dave you did use case 8?

dave: stuff has changed

<ChrisW> http://www.w3.org/2005/rules/wg/wiki/UC8_Worked_Example

dave: can do UC 8 next week

AllenG: can do UC3 following week

csma: move on to BLD



csma: action review
... sandro action 336?

sandro: continued

csma: 337?

harold: continued

csma: 338

chrisW: 338 is done (by Gary)

<Harold> New actions come in for me, too, with the discussion and work Sandro started for the successor to asn06.

<ChrisW> Harold, do you want to record some actions?

csma: jos to discuss changes to RDF compatibility section

<josb> http://www.w3.org/2005/rules/wg/wiki/Core/RIF-RDF_Compatibility

<Harold> No, that's an 'informal' action.

jos: cleaned it up....make more readable and to incorporate new items and resolutions
... also included new comments and discussion itmes
... biggest thing, found more elegant way to define the semantics, so now easier to read etc

csma: does anyone have clarification qustions?

chrisW: I have one...in common interpretations section condition 2
... what is condition 2 doing?

jos: just makes sure that whenever you use an element as a property then it is in the set Ip

AllenG: (technical discussion of condition 2)

chrisW: just says all slots are RDF properties?

jos: yes
... Michael had some skepticism concerning the semnatics?
... especially concerning the combination semantics; I responded in email

mkifer: I didn't get a chance to read it yet.

jos: let's continue in email

csma: did you (Jos) mean that an RDF graph can be translated into RIF rules?

jos: yes.
... actually translated to facts

csma: that means rif includes rdf?

jos: no...it means that if you want to use RDF with RIF you are implictly assuming this semantics

csma: does it mean that any RDF can be expressed as a RIF rule set?

jos: any kind of rdf entailment maps into entailment in rif

mkifer: this is the problem: the combined semantics isn't needed because rif already allows for that embdding

<josb> http://lists.w3.org/Archives/Public/public-rif-wg/2007Sep/0001.html

jos: let's continue that over email

mkifer: ok

csma: let;'s go over other issues in the email one-by-one

jos: 3 issues related to identifiers...
... absolute iri's versus rdf use of uri references
... might need a conversion?

dave: rdf uses "rdf uri references"
... they were trying to hone in on iri's before the irs spec was finalized
... i suggest we just leave it as iri's

<sandro> DaveReynolds: What the RDF spec uses is "RDF URI References" which is a confusing term. It's not "URI References". It was, rather, their best attempt to anticipate what IRIs would be. There may be a difference around spaces. I suggest we not dwell on any differences.

jos: I was confused by different statements in the specs

<sandro> Jos: I was trying to figure out if we need to take into account the conversions between URIs and IRIs.

dave: we don't need to worry about conversion

<sandro> DaveReynolds: I don't think we do. We just treat them as IRIs.

<sandro> +1 (just treat them as IRIs)

dave: in the iri specs conversion algorithms would be defined
... we certainly wouldn't define new conversions ourselves

csma: dave we are missing some of your audio....

<DaveReynolds> yes

csma: so the solution is to use absoluete iris

chrisW: do we need to refer to uris at all?

<DaveReynolds> exactly, don't point to any conversion, just talk about IRIs

jos: for the sake of rdf compatibility

sandro: rdf uri references are not uris

<josb> http://www.w3.org/TR/rdf-concepts/#section-Graph-URIref

chrisW: they were iri's before iri's were defined

sandro: I agree we dave that we don't need to worry about these issues
... we are basically tracking an evolving standard

<DaveReynolds> I proposed a form of words (derived from the SPARQL spec) before, I can find that again

sandro: just talk about iri's and maybe include a note to deal with special cases

jos: investigate further?

sandro: not us.

csma: do we need a formal decision?
... any objections to just talking about iri's?


<sandro> Sandro: The issue that I think is real is what we say you do about the odd little corner cases like an RDF URI Reference that is not an IRI -- eg one with a space in it.... I suggest we ignore this issue. (I think concurring with Dave on this suggestion)

jos: 2nd issue: some rdf literals are not strings accroding to xml schema strings
... but we didn't decide whether we want to go with xmls 1.0 or 1.1

<Harold> We certainly should be prepared for 1.1 and for now encourage RIF users to stay in the common subset.

jos: not clear about all the consequences of doing one or the other

chrisW: can we leave these decision to implementors of rif?

csma: do you mean in rif instance docs?

jos: yes we could, but then we should say something about rdf literals that are not xml 1.0 strings

chrisW: what does xmls 1.0 say?

<sandro> Jos: we need to say what to do if you see an xml 1.0 literal string

jos: doesn;t say anything

dave: we should leave the value space unconstrained (as in xmls 1.1)
... that doesn't stop people from using 1.0 libraries to process stuff
... in the spec we need to point to a specific spec
... 1.1 isn't at spec yet.

csma: but we never investigated the consequenses of using 1.1 as reference for xml types

dave: agreed...there may be other issues, e.g., builtins

csma: somebody to take an action with regard to xml datatypes included in rif
... volunteers/
... we need someone with good xml expertise
... gary?

gary: haven't been tracking 1.0 vs 1.1

<ChrisW> important point jos made, we can't just leave this up to implementors because we agreed to include XML datatypes directly as part of RIF syntax

dave: what about asking the xml schema group?

csma: yes

<DaveReynolds> not me

jos: i can
... but they haven't responded to earlier email yet

sandro: sending a comment to working group would be good
... i can try talking to the people directly, or send a message to working group

csma: actions?

<ChrisW> ACTION: debruij to send message to XML Schema WG comments list [recorded in http://www.w3.org/2007/09/04-rif-minutes.html#action01]

<rifbot> Sorry, couldn't find user - debruij

action taken by jos to send comment to xml schema working group

<ChrisW> ACTION: jdebruij to send message to XML Schema WG comments list [recorded in http://www.w3.org/2007/09/04-rif-minutes.html#action02]

<rifbot> Created ACTION-339 - Send message to XML Schema WG comments list [on Jos de Bruijn - due 2007-09-11].

jos: ill-typed literals in rif vs rdf
... treatment is different

<josb> http://www.w3.org/2005/rif/rdf-ill-typed-literal/uri-encode("s"^^u)

jos: I made a suggestion (see link in irc)
... map ill-typed literals to uris. Is this a good idea?

<sandro> rifbot, status

csma: don't ill-typed literals in rules make them uninterpretable and therfore who cares?

jos: they can occur in rdf data, so we need a way to treat them in rif

csma: ah this is for the combination semantics?

dave: this seems to be an unimportant case. in actual data you don't let ill-typed literals through. this isn't practically important
... just say the embedding only works for well-typed case

csma: basically agree with dave

jos: i don't agree. why not support all of rdf?

csma: it doesn't mean that rif rules can't interact with all of rdf data, it only means that some rdf data can't be translated into rif rues

<Harold> Jos' proposal re ill-typed literals could still come into RIF: where we deal with exceptions, partial compliance, etc., anyway.

<Harold> (see Sandro's earlier wiki page)

jos: but this comes into play with queries - rif query over rdf-data (containing ill-typed literals)

csma: but if rdf knows what to do with them, then rdf can deal with them

jos: reiterates point about query-answering

chrisW: something that understands rdf can do the translation for rif vs. rif itself knows what to do
... how complicated is this? if uncomplicated we can handle all of rdf

csma: but at what cost?

jos: only implementations that care about rdf would be affected

csma: but this contradicts your combination semantics argument,
... when you try to embed the rdf graph as rif rules you would get a syntax erro (with ill-typed literals)

chrisW: in support of csma's argument:

<sandro> Jos: I DONT propose we support ill-typed literals, instead I propose we translate to URIs.

jos: rif doesn't need to support ill-typed literals, we are translating to uri's

chrisw: so you are really in agreement (with csma)

<josb> http://www.w3.org/2005/rif/rdf-ill-typed-literal/uri-encode("s"^^u)

sandro: what do the uri's look like?

jos: shows link in irc

csma: ok

<MichaelKifer> should the data type name be part of such a uri?

jos: does this comply with best practices?

sandro: this is a pretty weird thing to do (but legal, i think)
... it;s a weird hack, but might be our best option

csma: any objections to doing this?

mkifer: basically a good idea, but need to work on details, e.g., other languages might want to use this mechanism

sandro: why did rdf do this? probably because it would be impossible to decide whether the literal is really ill-typed

csma: so we table this issue for now?

sandro: jos can you edit the page to show an actual example/

jos: yes

<josb> http://lists.w3.org/Archives/Public/public-rif-wg/2007Sep/0013.html

jos: there are 4 additional issues (see link in irc)

csma: once we resolve all these issues are we done with compability?

jos: it depends...doc would still need examples, etc. There are other related issues, but we are pretty close

csma: do we need to raise those other issues formally?
... yes

<ChrisW> ACTION: chris to investigate raising Jos' identified issues [recorded in http://www.w3.org/2007/09/04-rif-minutes.html#action03]

<rifbot> Created ACTION-340 - Investigate raising Jos\' identified issues [on Chris Menzel - due 2007-09-11].

csma: chris will you ask deborah to create those seven issues?

chrisW: ok
... sandro can you remove chris menzel from the list?

sandro: yes

<ChrisW> ACTION: cwelty to investigate raising Jos' identified issues [recorded in http://www.w3.org/2007/09/04-rif-minutes.html#action04]

<rifbot> Created ACTION-341 - Investigate raising Jos\' identified issues [on Christopher Welty - due 2007-09-11].

<ChrisW> zakim close item 5

Arch - Data Models

csma: action review

action 331 continued

action 330 done

csma: action 258 done?

dave: yes a long time ago
... we discussed 258 at the last f2f.

csma: action 258 closed

action 256 continued

<scribe> ACTION: 254 to semantics section for arch doc [recorded in http://www.w3.org/2007/09/04-rif-minutes.html#action05]

mkifer: at least telecon i mentioned splitting the arch doc into two.

csma: let's obsolete this action for now

action 254 closed

<DaveReynolds> http://www.w3.org/2005/rules/wg/wiki/Arch/Data_Sets

csma: dave do you want to discuss your changes

dave: see link in irc.
... this is a result of discussion at last f2f.
... there are now 3 subsections relating to differnt isues teased out
... how to identify the data set used by rules
... basically convey the metadata to give an identifier for data set
... 2nd section: data model identification
... how do yo tell the rule process what data model is being used?
... at f2f we agreed on supporting 3 data models
... i updated metadata vocabulary to accomodate those three
... 3rd section data-model usage: see email discussion about this

csma: so let;s use remaining time to how to embed metadata in rif

jos: there is no mechanism for specifying meta data in rif
... it's straigtforward to do it, but we need to decide what we want to include

csma: all we have is the proposal to use rdf to express metadata

dave: right.

Allen: I missed some of this...

<Harold> Dave, the current syntax proposal is in http://www.w3.org/2005/rules/wg/wiki/Core.

sandro: the question is related to extensibility.
... if extensibility is easy then we can let people write their own metadata schema

<ChrisW> who is cgi-irc?

csma: we need to get a better feeling of what kind of metadata would be required

<cgi-irc> apparently me for some reason... strange

<cgi-irc> Doug L

csma: if we only a small set of metadata maybe we can just get away with afew attributes and values

chrisW: this is orgthogonal to whther metadata is done in rdf

<ChrisW> -1 to extenc

<DaveReynolds> don't mind

<Hassan> -1 to extend

<sandro> adjourn

meeting adjourned

<DaveReynolds> bye

Summary of Action Items

[NEW] ACTION: 254 to semantics section for arch doc [recorded in http://www.w3.org/2007/09/04-rif-minutes.html#action05]
[NEW] ACTION: chris to investigate raising Jos' identified issues [recorded in http://www.w3.org/2007/09/04-rif-minutes.html#action03]
[NEW] ACTION: cwelty to investigate raising Jos' identified issues [recorded in http://www.w3.org/2007/09/04-rif-minutes.html#action04]
[NEW] ACTION: debruij to send message to XML Schema WG comments list [recorded in http://www.w3.org/2007/09/04-rif-minutes.html#action01]
[NEW] ACTION: jdebruij to send message to XML Schema WG comments list [recorded in http://www.w3.org/2007/09/04-rif-minutes.html#action02]
[End of minutes]

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$Date: 2007/09/04 16:31:40 $