14:49:13 RRSAgent has joined #rif 14:49:13 logging to http://www.w3.org/2008/08/12-rif-irc 14:49:19 zakim, this will be rif 14:49:19 ok, ChrisW; I see SW_RIF()11:00AM scheduled to start in 11 minutes 14:49:38 Meeting: RIF Telecon 12-Aug-08 14:49:45 Chair: Chris Welty 14:50:43 Agenda: http://lists.w3.org/Archives/Public/public-rif-wg/2008Aug/0019.html 14:51:06 ChrisW has changed the topic to: 12 Aug RIF Telecon Agenda http://lists.w3.org/Archives/Public/public-rif-wg/2008Aug/0019.html 14:51:25 clear agenda 14:51:30 agenda+ Admin 14:51:34 agenda+ Liason 14:51:39 agenda+ Action Review 14:51:44 agenda+ F2F11 14:51:47 agenda+ Core 14:51:51 agenda+ Test Cases 14:51:58 agenda+ Peter's review 14:52:02 agenda+ AOB 14:52:12 zakim, next item 14:52:12 agendum 1. "Admin" taken up [from ChrisW] 14:58:53 AxelPolleres has joined #rif 14:59:07 ChrisWelty has joined #rif 14:59:24 rrsagent, make minutes 14:59:24 I have made the request to generate http://www.w3.org/2008/08/12-rif-minutes.html ChrisWelty 15:00:34 mdean has joined #rif 15:01:01 SW_RIF()11:00AM has now started 15:01:05 rrsagent, make logs public 15:01:08 +[IBM] 15:01:16 zakim, ibm is temporarily me 15:01:16 +ChrisWelty; got it 15:01:58 +Mike_Dean 15:02:23 StellaMitchell has joined #rif 15:02:36 AdrianP has joined #rif 15:02:44 LeoraMorgenstern has joined #rif 15:03:31 +LeoraMorgenstern 15:03:35 are people having trouble with zakim? 15:03:39 +??P39 15:03:49 +AdrianP 15:03:52 +[IBM] 15:03:56 zakim, ibm is temporarily me 15:03:56 +StellaMitchell; got it 15:04:00 Zakim, mute me 15:04:00 AdrianP should now be muted 15:04:41 no problems with zakim for me 15:04:45 harold, are you coming? 15:05:22 +josb 15:05:27 josb has joined #rif 15:06:23 zakim, pick a scribe 15:06:23 Not knowing who is chairing or who scribed recently, I propose LeoraMorgenstern 15:06:27 Okay. 15:06:43 Scribe: LeoraMorgenstern 15:06:53 http://lists.w3.org/Archives/Public/public-rif-wg/2008Aug/att-0012/2008-08-05-rif-minutes.html 15:06:57 MichaelKifer has joined #rif 15:07:05 PROPOSED: Accept minutes of last week's telecon 15:07:12 RESOLVED: Accept minutes of last week's telecon 15:07:21 next item admin 15:07:28 any agenda amendments? 15:07:30 none 15:07:31 zakim, next item 15:07:31 agendum 2. "Liason" taken up [from ChrisW] 15:07:41 (that's liaison) 15:07:51 yes 15:07:58 Adrian: Health Care and Sciences will take up again in September? 15:08:05 +MichaelKifer 15:08:11 zakim, next item 15:08:11 agendum 2 was just opened, ChrisWelty 15:08:12 HCLS 15:08:16 zakim, next item 15:08:16 agendum 2 was just opened, ChrisWelty 15:08:20 +??P48 15:08:21 zakim, close item 2 15:08:21 agendum 2, Liason, closed 15:08:22 I see 6 items remaining on the agenda; the next one is 15:08:23 3. Action Review [from ChrisW] 15:08:25 zakim, next item 15:08:25 agendum 3. "Action Review" taken up [from ChrisW] 15:08:36 s/Health Care and Sciences/HCLS 15:08:37 http://lists.w3.org/Archives/Public/public-rdf-text/2008JulSep/0007.html ... yesterday's chat on rdf:text (former rif:text). 15:08:43 -??P48 15:08:45 Zakim, unmute me 15:08:46 AdrianP should no longer be muted 15:08:54 my actions: ACTION-551 is done, ACTION-552 is continued. 15:08:55 Adrian had action on making PRD conditions equivalent to BLD conditions. 15:09:03 +[NRCC] 15:09:08 Adrian: not finished 15:09:09 DaveReynolds has joined #rif 15:09:22 zakim, [NRCC] is me 15:09:23 +Harold; got it 15:09:26 Zakim, mute me 15:09:26 AdrianP should now be muted 15:09:28 Also, Axel had an action to summarize open DTB issues. 15:09:36 +??P48 15:09:42 Axel: continued. But will be ready by next week 15:09:54 Axel had action to remove section 4.3.5. Done. 15:10:15 Adrian, Stella (and Leora) had an action to discuss test cases. 15:10:21 That is pending discussion. 15:10:33 zakim, next item 15:10:33 agendum 4. "F2F11" taken up [from ChrisW] 15:10:57 F2F11 is scheduled fro Sept. 26-27. 15:11:12 Participants or potential participants are encouraged to make reservations now. 15:11:27 You need to get in early to get a relatively reasonable hotel rate. 15:12:02 Harold: recommendation of not-so-expensive hotel within walking distance 15:12:10 Chris: laughs 15:12:21 Chris: no IBM special rates for Manhattan 15:12:33 Jos: recommends Expedia 15:12:52 Chris: recommends looking in parts of Brooklyn close ot Manhattan and taking the subway. 15:13:02 s/close ot/close to/ 15:13:03 zakim, next item 15:13:03 agendum 5. "Core" taken up [from ChrisW] 15:13:31 +Gary_Hallmark 15:13:34 Need to take phone call 15:13:53 harold, can you scribe for a few minutes? 15:14:07 Ok 15:14:12 no functions should mean no lists 15:14:23 Scribe: Harold 15:14:49 no functions in heads might be enough. 15:15:01 decidability of reasoning 15:15:10 JeffP has joined #rif 15:15:26 (I am with Dave on phone) 15:15:33 Dave: Separation External/Internal may be an issue for lists. 15:15:45 I'm back; I can scribe again. 15:15:49 q+ 15:16:03 ack axel 15:16:14 zakim, DaveReynolds contains JeffP 15:16:14 +JeffP; got it 15:16:18 Scribe: Leora 15:16:35 why allow them at all? 15:16:56 q+ 15:16:57 -Gary_Hallmark 15:17:45 Chris: talking about a limited set of defined built-ins and no other user-defined functions 15:17:47 safety (i.e. no free vars in heads) + safety of built-ins (i.e. no otherwise unbound variables in built-ins) 15:17:51 +Gary_Hallmark 15:18:19 Jos: Axel was imposing certain restrictions on use of function symbols. 15:18:34 Jos: I see no reason for using function symbols except for external function symbols, 15:18:49 Jos: and restrictions are already defined here, so we have no problem with these. 15:18:53 MichaelKifer has joined #rif 15:19:02 So, we have some design principles for Core: Decidability would be #1(no function symbols). 15:19:10 zakim, mute me 15:19:10 MichaelKifer should now be muted 15:19:42 jos... assume: 15:19:42 a(x) :- a(y), external( add(y,1,x) ). 15:19:43 a(1). 15:19:52 so, externals can also be problematic. 15:20:02 Jos: You could devise certain restrictions (e.g., function symbols without variables) but I doubt they would be useful 15:20:28 Zakim, who is on the phone 15:20:28 I don't understand 'who is on the phone', AdrianP 15:20:33 right, that was why I suggestedt safety for head vars and vars in externals. 15:20:37 Zakim, who is on the phone? 15:20:37 On the phone I see ChrisWelty, Mike_Dean, LeoraMorgenstern, AxelPolleres, AdrianP (muted), StellaMitchell, josb, MichaelKifer (muted), Harold, DaveReynolds, Gary_Hallmark 15:20:41 DaveReynolds has JeffP 15:21:24 q+ 15:21:31 ack josb 15:21:37 Chris: what more than Datalog would we want in the core? 15:21:56 core: datalog + keep frame syntax 15:22:22 q+ 15:22:39 Axel: we could allow unbound variable in body as long it doesn't occur in the recursion. 15:22:40 ack axel 15:22:57 ack j 15:23:00 Jos: Rule A(x) will never terminate. 15:23:18 Jos: If you want any sort of safety, go for full-fledged safety. 15:23:27 Axel: was only referring to external predicates. 15:23:36 same applies for tautologies - so we need the Datalog safeness condition 15:24:33 s/safety/safeness 15:24:51 an extended notion of safeness for external preds would need binding patterns. 15:24:56 Chris: I don't see the need to go with binding patterns for core. 15:25:12 Chris: simplicity of implementation is one of the design requirements for core. 15:25:17 standards safety for both heads and externals is fair enough for core for me. 15:25:28 Jos: But guarantee of termination is also crucial. 15:25:36 q+ 15:25:48 jos' statement is not in conflict with chrisW's ... 15:25:58 Jos: Also, if there is a notion of safety, easier to implement.. 15:26:17 Chris: I don't find simplicity of implementation to be correlated with decidability. 15:27:16 +1 on decidability on core 15:27:16 yes. I'd even say, finite (minimal) models are a desideratum for core. 15:27:18 Jos: Certain algorithms are associated with guaranteed termination. 15:27:27 I prefer satisfiability for Core, but do not consider it a strong requirement 15:27:42 ack dave 15:28:00 q+ 15:28:29 q+ 15:28:54 ack h 15:29:00 Dave: 15:29:23 Dave: Feature of DTB that we have binding patterns there. (as summarized by Harold) 15:29:35 ack a 15:30:17 Axel, could you repeat that? 15:30:30 -Mike_Dean 15:31:10 Axel: I f we say every variable occurring in external predicate needs to be bound in non-external predicates, then we don't need binding patterns, because everything is bound. 15:31:20 What Axel describes is a notion of safeness 15:31:33 Binding patterns help in the definition of safeness 15:31:41 Axel: the idea of binding pattenrns is to loosen this restriction. If for example, we say we only need to bind two out of three variables. 15:32:08 it does 15:32:20 Axel: for Datalog, we don't have external predicates, so we would only have to say that variables appearing in predicates in the head also have to appear in the body. 15:32:53 q+ 15:33:04 Paraphrasing Axel, safeness can be seen as an overarching "binding principle", so no syntactic "binding patterns" would be needed. 15:33:23 dave, that would allow exactly the example I wrote above... 15:34:25 typically mode declarations are used to define such kinds of binding patterns, e.g. add(+,+,?) would mean first argument is bound input, second one too, third one can be output or input, i.e. free or bound 15:34:52 ack j 15:35:13 Jos: I don't think Axel's strict defintion of safeness is useful. 15:35:26 Jos: Definition should take external predicates into account. 15:35:29 not in the standard datalog sense... 15:35:32 In LP, "binding patterns" were often called "mode declarations". Introducing explicit "mode declarations" syntax for Core would be problematic: An extralogical feature that we may not want througout all RIF dialects (e.g. in BLD). 15:35:37 -Gary_Hallmark 15:35:53 Jos: More precisely, one uses external predicates to define safeness. 15:36:34 Harold: not proposing mode declarations could be part of user rules, just defined in the spec as restrictions on using of DTB fns/preds 15:36:34 Jos, could you repeat that? 15:36:40 Jos: 15:36:59 the thing is that a binding pattern for my example, alone would not "save" you... the extension of a() would still be infinite. 15:37:07 Chris: Youre' talking about having a mechanism to specify whether a variable needs to be free or bound? 15:37:19 Jos: I don't think we need anything more. 15:37:29 i.e. either you take safety in the strict sense OR you take binding patterns plus safe recursion. 15:37:44 Axel: agreed 15:37:46 jos, do you agree? 15:37:56 not all Datalog engines support binding patterns / mode declarations 15:38:14 Chris: do people agree with Jos? (No, seems, that Axel doesn't.) 15:38:30 Dave, Yes, that's fine. 15:39:24 Axel: either take strict safety or restrictions on bindings in recursion. 15:39:37 +Gary_Hallmark 15:40:39 Jos: yes, Datalog and the addition of external predicates does complicate things. 15:41:19 Datalog semantics for hybrid Ontology - rule systems have been defined, it is the same problem 15:41:39 Core as datalog + a limited set of datatypes & builtins 15:41:40 David: 15:42:57 Chris: We need to make sure Core has certain attributes--- e.g., decidability, ease of implementation 15:43:06 Core should be easy to implement, decidable?, tractable?, extendable to BLD & PRD 15:43:13 Harold: We need to keep PRD in mind --- what do we bring from PRD to core? 15:43:14 Zakim, unmute me 15:43:14 AdrianP should no longer be muted 15:43:23 Harold: E.g., Christian's notion of negation? 15:43:38 Yes. 15:44:13 Because we might adapt FLD's/BLD's negations for that. 15:44:23 Adrian: And also Assert action 15:44:32 Gary: same as frame formula or term in PRD 15:45:02 We have called Assert-only PRD "Pur Production Rules". 15:45:17 note that Datalog safety does not extend straightforwardly to allowing discjunction in the body, but we excluded that already, right? 15:45:20 the semantics of the head in core for PRD would then be an assert 15:45:21 s/Pur Production Rules/Pure Production Rules/ 15:45:38 right 15:45:42 Axel: right, I think we agreed to exclude that last week 15:45:50 yes, pure production rules without negation would be Core (from the PRD perspective) 15:46:06 Chris: someone has to step up to take on the job of writing this all up. 15:46:06 Zakim, mute me 15:46:06 AdrianP should now be muted 15:46:12 Chris: Looking for volunteers. 15:46:16 Zakim, unmute me 15:46:16 AdrianP should no longer be muted 15:46:21 q+ 15:46:37 Harold: Will work on this from the BLD point of view. Perhaps some PRD people will join. And perhaps Dave? 15:46:51 And Axel and Adrian also. 15:47:12 I would join from the PRD perspective, since I will work on the conditions of PRD anyway 15:47:12 q- 15:47:13 Chris: Harold, can you start the wiki page for the core document? 15:47:17 Zakim, mute me 15:47:17 AdrianP should now be muted 15:47:19 action: harold to start a core draft wiki page 15:47:19 Created ACTION-556 - Start a core draft wiki page [on Harold Boley - due 2008-08-19]. 15:47:26 zakim, next item 15:47:26 agendum 6. "Test Cases" taken up [from ChrisW] 15:47:37 Zakim, unmute me 15:47:37 AdrianP should no longer be muted 15:47:57 http://www.w3.org/2005/rules/wiki/Test 15:48:19 Adrian: 15:48:32 Adrian: This is the document that we're writing for test documents 15:48:40 http://www.w3.org/2005/rules/wiki/TCS 15:48:49 Adrian: There's also another document (the TCS doc) intended for discussion) 15:48:53 DaveReynolds has joined #rif 15:49:13 Adrian: Test document will be the official working draft for test cases 15:49:34 Adrian: TCS doc is intended for discussion of questions and issues. 15:49:59 Adrian: Stella proposed we first discuss purpose of test suite. 15:50:14 Adrian: Do we want to define test suite for conformance? 15:50:29 Adrian: Or do we want to just give examples for test cases? 15:51:11 Adrian: Or will there also be test cases for validating implementation? 15:51:50 Adrian: two parts: 1. Define test suite (for BLD, PRD, built ins for DTB) 15:52:01 and could be informative or conformant. 15:52:09 q+ 15:52:41 2. Also might give concrete xml syntax for specifying test cases. 15:53:07 Chris: Why not just specify test cases in xml of dialect? 15:53:30 Adrian, does your "test theory" already distinguish consumers and producers? http://www.w3.org/2005/rules/wiki/BLD#Conformance_Clauses 15:53:42 Adrian: Perhaps current dialects might not be expressive enough for some tests. 15:54:01 Chris: encourage to start small, and focus on test cases for BLD. and soon, PRD. 15:54:17 Chris: but would be hesitant to start inventing a new dialect. 15:54:52 Chris: Be careful with test cases for PRD, because it's evolving so quickly. Wait till it's stable. BLD, on the other hand, is stable. 15:55:11 Chris: And it's critical for next step of BLD --- a call for implementation --- 15:55:16 Chris: that there are test cases. 15:55:17 ack d 15:55:39 Dave: 15:56:04 Dave: Should be neither conformance suite nor informative, but normative 15:56:44 Dave, using finitely many tests, you can anyway only disprove conformance, not prove it. 15:57:00 Chris: We're not imagining a test suite is exhaustive in terms of the dialect. 15:57:18 Chris: Being able to run the test suite does not guarantee full compliance; not sure it's possible to have such a test suite. 15:57:34 Adrian: Another question: which kind of test cases? 15:57:45 Adrian: initial categorization in test case document 15:57:57 http://www.w3.org/2005/rules/wiki/Test 15:58:09 MichaelKifer has joined #rif 15:59:06 Chris: why have different categories? 15:59:16 Adrian: to distinguish different test suites 15:59:27 Adrian: also may facilitate collection process from community 15:59:32 Chris: 15:59:47 Chris: don't really see point of classification system prior to the tests. 16:00:04 Chris: why not come up with test cases first? 16:00:22 Chris: tests may wind up in multiple categories 16:00:45 Chris: first get tests, then see if some natural ordering comes from them. 16:01:16 Chris: what are some of the important features of BLD to test? Important to have test cases of classifcation, of forms, of external functions, etc. 16:01:29 Chris: Work toward more explicit test cases. 16:01:31 q+ 16:01:31 q+ 16:01:41 http://www.w3.org/2005/rules/wiki/Category:Test_Case 16:01:44 ack d 16:01:58 Dave: main thing are validation tests, entailment tests, etc. 16:02:13 Dave: best to concentrate on these 16:02:15 ack l 16:02:41 some test cases are here http://www.w3.org/2005/rules/wiki/Category:Test_Case 16:04:55 Chris: I gave a RIF presentation 2 weeks ago; first question was: do you have any examples; and I suspect that's going to be true for anyone who gives a presentation on RIF. 16:05:13 Chris: Since there are lots of people who learn from examples, not from reading documents. 16:05:55 Chris: Jeff, you expressed interest in submitting some examples. Would you still like to do this? 16:06:10 Jeff: Yes, I have a colleague of mine just joined the WG and will be doing this. 16:06:36 Zakim, mute me 16:06:36 AdrianP should now be muted 16:07:08 Zakim, unmute me 16:07:08 AdrianP should no longer be muted 16:07:08 chris: I can officiall assign the action to him when he officially joins the WG and is on a telecon. 16:07:32 Chris: Anyone else who has even the simplest examples around should submit them. 16:07:50 Adrian: Should we have an open call for test cases? 16:08:12 Adrian: 16:08:29 Chris: We do have that: we have the wiki and a wiki template for writing test cases. 16:08:40 Chris: What's the process for someone to create a new test case? 16:09:00 Adrian: For category page for test cases, there is a template for creating test cases; template is shown on bottom of page. 16:10:14 Chris: would be better to just click on a button and get a template. 16:11:07 Chris: 16:11:12 http://www.w3.org/2005/rules/wiki/Test_Case_Example 16:11:26 action: Chris to make WG call for use cases 16:11:26 Created ACTION-557 - Make WG call for use cases [on Christopher Welty - due 2008-08-19]. 16:11:29 Chris: I will make a call for the working group to submit test cases. 16:11:35 q+ 16:11:44 ack l 16:15:43 http://www.w3.org/2005/rules/wiki/Test_Case_Format 16:16:11 zakim, next item 16:16:11 agendum 7. "Peter's review" taken up [from ChrisW] 16:16:18 Zakim, mute me 16:16:18 AdrianP should now be muted 16:16:30 http://lists.w3.org/Archives/Public/public-rif-comments/2008Aug/0000.html 16:16:38 16:16:48 http://www.w3.org/2005/rules/wiki/Response_to_PPS4 16:17:55 Chris: Peter Patel-Schneider wrote a critique of BLD; seems to be a lot of confusion over terminology. 16:18:04 action: debruij2 to draft initial response to PFPS4 16:18:04 Sorry, couldn't find user - debruij2 16:18:04 Chris: Jos, would you take an action to respond? 16:18:07 Jos: yes. 16:18:16 action: jos to bla 16:18:16 Sorry, amibiguous username (more than one match) - jos 16:18:16 Try using a different identifier, such as family name or username (eg. jdebruij2, jderoo) 16:18:25 action: jdebrui2 to draft initial response to PFPS4 16:18:25 Sorry, couldn't find user - jdebrui2 16:18:32 action: jdebruij2 to draft initial response to PFPS4 16:18:32 Created ACTION-558 - Draft initial response to PFPS4 [on Jos de Bruijn - due 2008-08-19]. 16:18:46 zakim, next item 16:18:46 agendum 8. "AOB" taken up [from ChrisW] 16:18:54 zakim, list agenda 16:18:54 I see 1 item remaining on the agenda: 16:18:55 8. AOB [from ChrisW] 16:19:16 -Harold 16:19:16 Chris: proposal to adjourn 16:19:18 -StellaMitchell 16:19:20 zakim, list attendees 16:19:20 As of this point the attendees have been ChrisWelty, Mike_Dean, LeoraMorgenstern, AxelPolleres, AdrianP, StellaMitchell, josb, MichaelKifer, Harold, Gary_Hallmark, JeffP 16:19:23 -Gary_Hallmark 16:19:25 -AdrianP 16:19:28 -josb 16:19:29 -MichaelKifer 16:19:32 -DaveReynolds 16:19:39 -AxelPolleres 16:19:44 Regrets: Sandro Hawke MohamedZergaoui 16:19:50 rrsagent, make minutes 16:19:51 I have made the request to generate http://www.w3.org/2008/08/12-rif-minutes.html ChrisWelty 16:23:10 -ChrisWelty 16:23:12 SW_RIF()11:00AM has ended 16:23:13 Attendees were ChrisWelty, Mike_Dean, LeoraMorgenstern, AxelPolleres, AdrianP, StellaMitchell, josb, MichaelKifer, Harold, Gary_Hallmark, JeffP 17:44:21 RRSAgent has joined #rif 17:44:21 logging to http://www.w3.org/2008/08/12-rif-irc