RIF Telecon 26-Aug-08

26 Aug 2008


See also: IRC log


Mike_Dean, ChrisW, +1.631.833.aaaa, Sandro, MichaelKifer, +1.212.781.aabb, DaveReynolds, LeoraMorgenstern, StellaMitchell, AxelPolleres, +0122427aacc, yuting, StuartTaylor, csma, +49.351.463.4.aadd, AdrianP, Harold, JeffP, +1.503.533.aaee, GaryHallmark
JosDeBruijn, Hassan_Ait-Kaci
Chris Welty





<ChrisW> Scribe: MichaelKifer

<ChrisW> http://lists.w3.org/Archives/Public/public-rif-wg/2008Aug/att-0107/19082008-rif-minutes.html

<ChrisW> PROPOSED: Accept minutes of Aug 19 telecon

<ChrisW> RESOLVED: Accept minutes of Aug 19 telecon


<ChrisW> Scribe: Harold

Sandro: OWL-RL is a profile for OWL coupled with rule engines.
... It may fit BLD or FLD.

<DaveReynolds> I would hope OWL-RL fits within Core

Chris: Can we ask them to publish such rule bases in RIF XML syntax?

Sandro: Yes. at some point.

Mike: Is it renamed from earlier name?

Sandro: Evocative of RuLes.

<JeffP> QL

<AxelPolleres> URL?

<JeffP> http://www.w3.org/2007/OWL/wiki/Profiles

<sandro> yeah, more specifically: http://www.w3.org/2007/OWL/wiki/Profiles#OWL_2_RL

Action review

<AxelPolleres> http://www.w3.org/2007/OWL/wiki/InternationalizedStringSpec

<AxelPolleres> ... need to check the implications of Botris Motik's reply to me.

<ChrisW> http://www.w3.org/2005/rules/wiki/Response_to_PPS4

Chris: Axel keep looking at comments wrt DTB relationships.

<ChrisW> ACTION: axel to look at DTB comments in Peters message [recorded in http://www.w3.org/2008/08/26-rif-minutes.html#action01]

<trackbot> Created ACTION-568 - Look at DTB comments in Peters message [on Axel Polleres - due 2008-09-02].

<AdrianP> ok, thanks Sandro

<AdrianP> http://www.w3.org/2005/rules/wiki/PRD#Rules_instantiation:_INSTANTIATE

Adrian: Have reformulated, interacting with Christian, the semantics of the PRD instantiate function.


Harold: Who is in which hotel?

<sandro> Holiday Inn Midtown at $306/night

Mike: NJ, $169

<sandro> Holiday Inn Midtown at $306/night 440 WEST 57TH ST 1-212-5818100

<AxelPolleres> Portland Square Hotel (47th street), sharing with jos... makes it cheaper.

Test Cases

Leora: Issue of more user friendly PS.
... Adrian has proposed improvements.
... We want to bring up this issue.

Chris: Current PS makes it difficult to talk about RIF.

<csma> Hear, hear!

Leora: It's plain hard. Extra burdon on users.
... Would be good to have other syntax.

<ChrisW> http://www.w3.org/2005/rules/wiki/UCR#Use_Cases

Leora: Maybe with preprocessor to map to current PS.

Chris: What you use is a bunch of shortcuts with "if...do..." production rules.

<AxelPolleres> I had some comments on the shortcuts suggested for arithmetics and comparison... http://lists.w3.org/Archives/Public/public-rif-wg/2008Aug/0124.html not sure whether the mail was clear, but I can explain it.

Adrian: Currently Prolog symbol for "is implied by".

<AxelPolleres> What about triple syntax a la N3?

Chris: Also "->" is not a good symbol for slots.

Axel: Some examples use arithm shortcuts.

<GaryHallmark> what about colon instead of ->, e.g. ?o[k1:v1 k2:v2]

<AdrianP> you mean, e.g. ">" "<" "!=" "=" "<=" ">=" as in programming languages

<AdrianP> instead of e.g. External(pred:numeric-less-than(1 2))

<csma> Why not =, since we currently have only an equality accessor (for slots)?

<csma> as in object[property=value]?

Adrian: Parser can figure out distinctions via arg types (e.g. two numbers).

Axel: Makes sense.

Sandro: I'm highly dubious.
... It would be a half-way rule language.
... Lets either use XML or a real rule language.
... Run UC: Only XML.
... Read UC: Use your own favorite syntax

<AdrianP> the main intention of the abridged syntax is to make it easy to write down and read rules

<AxelPolleres> in xpath, etc you have '+','-', but type-checking of the operators is supposed to take place before it is chosen which add or subtract function is actually meant.

Chris: Requires a tool.

Sandro: Yes. Need bootstrapping.

Christian: Two questions:

<AxelPolleres> ... same for comparisons, i.e., any xpath processor should be able to deal with +,-, >, <, etc. for various datatypes.

Christian: 1) What's the purpose of non-abridged syntax if we have an abridged one?

<StellaMitchell> PS is normative, I think

<LeoraMorgenstern> Christian, the semantics have been defined in terms of the presentation syntax, no?

<LeoraMorgenstern> So it makes sense to keep that.

<LeoraMorgenstern> But you still want something that's easier to read and write.

Christian: 2) There is a case where you need to translate/produce a RIF doc with a specific rule that is not in XML
... When you need to produce a rule set.

<DaveReynolds> Stella - the "mathematical english" is normative, the presentation syntax and it's EBNF is non-normative, the semantics actually refers to the mathematical English - at least that's how I understand it.

Chris: Not translation test cases now. But entailment test cases.
... Otherwise we would need whole suites of cases for each language.

Axel: Uneasy with +, -, *, / etc. only for numbers.
... Other languages have such symbols also for other datatypes.

<StellaMitchell> dave, the spec just says "the presenation syntax is normative" (but not the ebnf)

<AdrianP> such abreviations are quite common in nearly all programming languages

Chris: Issue if it's better than current PS.

Axel: Agree, but kind of half-way.

<DaveReynolds> Stella - yes, sorry.

<JeffP> still not clear why we need another syntax

Chris: Alternative would be to define a new syntax.

<LeoraMorgenstern> JeffP, it's because the current PS is really hard to read and write.

<LeoraMorgenstern> and we are afraid it will affect adoption of RIF.

<JeffP> LeoraMorgenstern, thanks - is PS going to be replaced by the new one?

Axel: Should we use the Abridged Syntax but mark it as not covering more than numerics?

<DaveReynolds> Leora - in that case it needs a formal definition, the current defn is ambiguous

<LeoraMorgenstern> Dave, I agree.

Chris: Will need to make status of Abridged Syntax more explict.

Axel: yes.

Leora: Discussed various more cases.

<LeoraMorgenstern> http://www.w3.org/2005/rules/wiki/Category:Test_Case

Leora: Quite comprehensive now.

<AxelPolleres> We should mention explicit that our abbreviations for comparison operators and arithmetic operators *only* apply to numeric datatypes, *as opposed to* the more generic use of these abbreviations in languages such as XPATH

<AdrianP> e.g. http://www.w3.org/2005/rules/wiki/Chaining_strategy_numeric-add-1

Leora: Chaining strategy test case brought in by Axel.

Axel: Dual versions, behaving differently in (naive) forward and backward engines.
... Cannot just materialize.

Leora: It would help if people make the "Discussion" slot more explicit.
... Distinguish various cases.
... Overarching argument.
... Otherwise readers can get lost.

<AdrianP> I would propose to group test cases to test suites which have a context

Chris: E.g., what Axel just described on the phone should be in the document.

Axel: Fine.

<StellaMitchell> and maybe we can use seeAlso field to reference related test cases from test cases

Sandro: "Description" vs. "Discussion" slots, with linking.

Adrian: Concept of test suite. One test case can refer to the other.

Gary: Axel's chaining strategy test cases are also legal PRD, which is good.

Leora: Stella and I translated a number of UCs.

<StellaMitchell> gary: cases that apply to BLD and PRD could be of dialect Core

Leora: Dave has a named-arg uniterm ex.
... Next week there will be more.


<ChrisW> http://lists.w3.org/Archives/Public/public-rif-wg/2008Aug/0074.html

Chris: Let's go over eds note list.

<AdrianP> Other open issues of Test Cases are e.g. the set of properties which we have define or the translation from the WIKI version into a concrete XML syntax

Chris: All shortcuts should ultimately be in one place.

Axel: Section 2.2 should explain rdf:text shortcut.
... in abridged PS, it would already be it.

Chris: Separate wiki page?

<csma> +1 for having the shortcuts and abridged syntax all in one place, and that is not DTB

Axel: No problem, but then remove it from all other places.

<AdrianP> yes, good idea

<AdrianP> YES

<AdrianP> yes

<ChrisW> ACTION: adrian to create page that documents abridged syntax [recorded in http://www.w3.org/2008/08/26-rif-minutes.html#action02]

<trackbot> Sorry, amibiguous username (more than one match) - adrian

<trackbot> Try using a different identifier, such as family name or username (eg. agiurca, apaschke)

<AdrianP> it will make it easier for programmers

<ChrisW> ACTION: apaschke to create page that documents abridged syntax [recorded in http://www.w3.org/2008/08/26-rif-minutes.html#action03]

<trackbot> Created ACTION-569 - Create page that documents abridged syntax [on Adrian Paschke - due 2008-09-02].

Axel: Predicate that takes rdf:text and language range, matching eg all "en" tags.

Dave: In SPARQL there is also a lang matcher.

Axel: A bit awkward.

Chris: Can you extract lang. tag?

Axel: Yes, but not typical use case.

Dave: Fine. Alg the same, just args different.
... Can lang tag be empty xs:string?

Axel: We agreed this should not cause any harm.

Chris: Does this change anything in the def of matching lang tag?

Axel: We could define it only for non-empty lang tags.

Dave: Same for func:lang(...)?

Axel: Dont see a problem.

Dave: Normally no need for testing non-emptiness.
... How does this affact RDF Compatiblity?

Axel: We already have different treatment there.
... treat plain literals same as those typed with xs:string.
... which is different from RDF.

Dave: According to D-entailment it is the same.
... But yours not.

Axel: Empty lang tags do not occur in RDF, so it doesnt matter.

Sandro: Syntax error in RDF.

Chris: OK. So in RDF?

Axel: Plain literals.
... So the rdf:text task force is looking into unifying them.

Sandro: No problem because rdf:text does not normally occur in RDF.

Dave/Sandro/Axel: More discussion about datatype system, performance issues, ...

Chris: Record as an issue and move on?
... Dave you are not sure?

Dave: No formal objection, need to think more about it. Feels awkward, perhaps better to raise an error instead.

Sandro: Regarding what impacts all of this might have: More on OWL than on RIF in Jena.

<ChrisW> curious

<sandro> AxelPolleres, how were you dialed in....?

<AxelPolleres> oops

<AxelPolleres> redialing

Dave: Consult with my group and come back if there is a concern.


<sandro> http://www.w3.org/2005/rules/wiki/Publicity

Chris: Much more active Public Relations need be done.

<sandro> see for contrast http://www.w3.org/2007/OWL/wiki/Publicity

<sandro> old version.... http://www.w3.org/2005/rules/wg/wiki/Outreach

Chris: Use it to record who sent which msg where.
... What advertising has anyone done?

<DaveReynolds> Re rif:text and RDF compatibility - there isn't a problem. In the RDF spec there is the statement "The xml:lang="" form indicates the absence of a language identifier" which is therefore compatible with the proposed approach. Sorry to have diverted the discussion.

<AxelPolleres> I contacted some LP related lists... will add on the wiki

Chris: No one else? We need to start doing it NOW.
... Can we find Press Release?

<sandro> Press release: http://www.w3.org/News/2008#item132

Adrian: Some LP lists.

Axel: Sent to Enrico, the editor of the LP Newsletter.

<AdrianP> xsb-development@lists.sourceforge.net

Axel: If we have a Press Release, we can bring it in faster, otherwise 3 months.

<AxelPolleres> I did the following:

Dear all,

I would like to draw your attention to the recent drafts published by

the World Wide Web Consortium's Rule Interchange Format (RIF) working

group, towards an interchange format for rules languages:

The current specification is a collection of 6 documents published at

the following URLs:

1. RIF Use Cases and Requirements


2. RIF Basic Logic Dialect


3. RIF Framework for Logic Dialects


4. RIF RDF and OWL Compatibility


5. RIF Production Rule Dialect


6. RIF Datatypes and Built-Ins 1.0


The Working Group seeks public feedback and comments on these drafts on

the following mailinglist at the following email-address:


with best regards,


Sandro: You have to target your audience / your community with customized versions for each mailing list.

Christian: Do not use BCC, but FWD your mailouts to Sandro.

Chris: We have to stress that BLD is in LC.

Dave: Main semweb lists.
... Jena Dev list, too

<DaveReynolds> I did publicize inside HP as well.

Gary: Send it to Oracle list and to Jess.

<AdrianP> yes there is RIF demo at the Orlando conference

<AdrianP> yes, can send it to the RuleML-2008 board

<sandro> my posting to semantic-web@w3.org http://lists.w3.org/Archives/Public/semantic-web/2008Aug/0002.html

<sandro> I'll send to swi-prolog@iai.uni-bonn.de

<sandro> semantic-web@w3.org done.

Harold: NRC and RR Board/Conf

Sandro: SWI Prolog list

<JeffP> Hi

Jeff: I'll send it to Aberdeen's rule-related projects

Mike: semweb list we covered already

<JeffP> Yuting, do you have any other suggestions?

Mike: DARPA projects

<StellaMitchell> no, no lists

<StellaMitchell> :-)

<yuting> No idea at the moment, beside the MOST project partners

Sandro: Even if we don't get much feedback, we have to present evidence that we mailed it out widely.

<StellaMitchell> I'll try

<csma> I plan to send an announcement on the JavaRules list, the Business Rules community list, the various PRR lists, the MISMO BREW list

Adrian: XSB and JBoss.

Christian: see above. Yahoo Group.

<sandro> chris: odm, common-logic,

Chris: ODM, Common Logic.

<AxelPolleres> sparql-dev?

Christian: Mark could mention it on his blog.

Chris: Other blogs. Sandro, Linked-Data community?

<AxelPolleres> public-lod@w3.org

<ChrisW> scribe for next week: GaryHallmark


<yuting> I could also send it to the ai-and-web-in-china, a google group

<DaveReynolds> bye

<JeffP> thanks, bye

<AdrianP> bye

Summary of Action Items

[NEW] ACTION: adrian to create page that documents abridged syntax [recorded in http://www.w3.org/2008/08/26-rif-minutes.html#action02]
[NEW] ACTION: apaschke to create page that documents abridged syntax [recorded in http://www.w3.org/2008/08/26-rif-minutes.html#action03]
[NEW] ACTION: axel to look at DTB comments in Peters message [recorded in http://www.w3.org/2008/08/26-rif-minutes.html#action01]
[End of minutes]

Minutes formatted by David Booth's scribe.perl version 1.133 (CVS log)
$Date: 2008/08/26 16:32:53 $