00:00:04 sandro has joined #rif 02:37:34 josb has joined #rif 08:28:39 patranja has joined #rif 13:49:57 RRSAgent has joined #rif 13:49:57 logging to http://www.w3.org/2007/02/28-rif-irc 13:50:01 Agenda for Today: 13:50:08 - F2F6 13:50:09 Deborah_Nichols has joined #rif 13:50:20 - Architecture Document 13:50:30 - Core OWL and RDF Compatibility 13:50:35 - RIFRAF 13:50:38 - Demos 13:51:37 (Sandro - can u pls give URL pointers to relevant documents? Thanks) 13:52:04 i was just typing what was on the screen. 13:52:24 (thanks - sorry for being so demanding... :-) 13:52:27 ChrisW has joined #rif 13:52:29 topic: F2F6 13:52:40 Harold has joined #rif 13:52:43 scribenick: Harold 13:52:45 Leora, correction, we will start RIFRAF at 11:30 13:52:54 Meeting: RIF F2F5 Day 3 13:53:06 allen has joined #rif 13:53:12 Chair: Christian de Sainte Marie and Chris Welty 13:53:28 RRSAgent, make record public 13:53:31 RRSAgent, make minutes 13:53:31 I have made the request to generate http://www.w3.org/2007/02/28-rif-minutes.html sandro 13:54:11 -> http://www.w3.org/2005/rules/wg/wiki/F2F6 F2F6 13:55:38 AxelPolleres has joined #rif 13:55:40 Topic: F2F6 13:57:07 Jos: There are several events collocated with ESWC2007 and RR2007 in Innsbruck, June 07 13:58:00 +Axel_Polleres 13:59:18 mikes? 14:00:04 The agenda is now on the wiki for today 14:01:14 Within 2 weeks (March 13) possible other proposals, with proposed dates etc. 14:01:25 Decision on Tuesday after. 14:02:03 (for what it's worth - we can hear no one except Christian) 14:02:33 Topic: RIFRAF 14:02:36 I can 14:05:50 Axel: Why an Ontology for RIFRAF 14:06:23 ... Earlier email: OWL Ontology. 14:07:04 ...Idea: formalize discriminators in an ontology to get a classification schema. 14:07:13 PaulVincent has joined #RIF 14:08:13 (more: see Axel's slides) 14:18:37 q+ 14:19:37 Excellent work Axel! 14:19:42 Axel: Summary: Base Ontology and Metamodel should be the same. Wants others to join. 14:19:44 Indeed! Very nice, Axel. 14:20:25 q+ 14:20:25 Deborah has joined #rif 14:20:27 Leora: If the Core can't express something, then why it should be modeled in RIFRAF? 14:20:58 Axel: Gradual refinement. 14:21:30 "should base ontology be more expressive than core"? 14:21:42 s/If the Core can't express something, then why it should be modeled in RIFRAF?/Base ontology should be somehow more expressive than the Core./ 14:22:17 Leora: There should be some way to distinguish Core and non-Core classes. 14:22:54 q? 14:22:54 Chris: we're calling it the Abstract Syntax, not "Metamodel", because metamodels often have other stuff. 14:22:58 Chris: Yesterday we agreed to call 'Abstract Syntax' what we do in UML, not call it 'metamodel'. 14:23:29 Axel and Leora: OK. 14:24:12 q- LeoraMorgenstern 14:24:48 q+ for my second point: semantic discriminators 14:24:58 Christian: Plse clarify on RIFRAF: Isn't it to help us define new dialects, using features, classes, etc., first for Core, then next family, etc. 14:25:06 q+ to discuss my second point: semantic discriminators 14:25:12 I would have some adhoc comment on that. 14:25:19 q+ 14:25:32 ... You seem to see RIFRAF as a posteriori description of dialects, not what should go into dialect. 14:26:04 Axel: While, yes, this was planned, then nothing has happened, so went bottom-up instead of top-down. 14:26:27 ack Hassan 14:26:37 :-) 14:26:51 ... on hassan. 14:26:58 Hassan: Excellent work. Use of Prolog: don't apologize, this is great. 14:27:38 operational/declarative way to check rulesets was exactly what I proposed. 14:27:53 ... At least we have operational way of checking. From informal to formal. Make experiment with a methodology. Axel proposed operational methodology (happens to be in Prolog). Way to test. 14:27:54 ie. we can formalize dialects on such "programs". 14:28:25 ... Second: Can now try to characterize what is missing, so as to suggest new discriminators. 14:28:48 "operationalizing desciminators" 14:29:27 +1 to allen that the semantic discriminators will be much tougher. for these we will also need additional annotations. 14:29:41 Allen: Very impressed by Axel's work, agree with Hassan. What about semantic discriminators? Cannot all be operationalized (e.g. halting problem). 14:29:53 +1 to allen, as well, and I'm taking myself off the queue, because Allen made my point 14:29:55 q- 14:30:08 Chris: Current focus on syntactic discriminators. Would it work for semantic ones? 14:30:23 Allen: Would need to formalize model theory. Finite models? 14:30:36 Hassan: Those who define the languages must decide that. 14:30:45 q? 14:30:54 ack axel 14:31:16 Axel: Agree with Allen: will need semantic annotations, since we cannot see such properties from the rules themselves. 14:31:42 Allen: Is RIFRAF supposed to Rulesets or to Dialects? 14:31:57 s/supposed to/supposed to apply to/ 14:32:02 q+ 14:32:09 q- 14:32:17 Axel and Allen: Worthwhile exercise. 14:32:52 Hassan: System not to be used parser or something (feeding in lang. description and generate parser). 14:32:52 +1 to Hassan; but the point then is to see the relationships among different languages 14:33:30 ... Rather map language into ontology. Someone has already written discriminators, since have already understood them. 14:33:56 Chris: Someone gives values to these features, then get right dialect. 14:34:03 Hassan: Exactly. 14:34:09 that's fine with me... It is a declarative way to specify what a rule dialect (syntactivally) defines, but also (as a side-effect you want, to check a ruleset. 14:34:32 Chris: Axel's examples are on rules, not on dialects. 14:34:45 this (adding ruleset as argument) can be refined 14:34:46 Hassan: Yes, but methodology can also be used for dialects. 14:35:15 Chris: Can you give such as classification? 14:35:48 Axel: Yes. Declarative way to find out if dialect fulfills features. 14:36:13 Chris: Constraints on rules themselves. Domain of discours: syntactic parts of rules. 14:36:43 ... But we want syntactic-semantic features of a dialect, not of rules themselves. 14:37:14 Axel: Dialects could be defined on top rules and rulesets. 14:37:25 +1 with Allen! 14:37:34 Allen: Need a tool to check feature-dialect mapping. 14:37:40 q? 14:37:41 q+ 14:37:43 Good tool to experiment with... 14:37:58 Dave: How can you have such a tool: chicken and egg problem. 14:38:14 q- 14:38:26 ... Notion of fully operationalizing: stay back from. 14:39:06 josb has joined #rif 14:39:17 +1 to dave Yes, it needs/is the RIF! That's why i said this is just a different way of writing down the metamodel, an that should be elaborated in parallel with the metamodel/language. 14:39:18 Leora: Rules and/or Ruleset? The whole set only makes an informal spec a theory. 14:39:48 Chris: Distinction is between Rules/Ruleset and Dialects. 14:40:31 Axel: Should serve as RIFRAF Core that can be gradually extended. 14:41:04 q 14:41:08 q+ 14:41:15 Chris: At least for Phase 2 of RIF we need identify (more completely the) family of rule languages (dialects). 14:41:33 Axel: We also need to top-down part? 14:41:37 Chris: Yes. 14:42:10 Leora: Relative complex predicates to decide what goes into a language. Metapredicate talking about existence. 14:42:14 ack leora 14:42:42 Chris: Think about RIFRAF questionnaire: "Does this language have this feature?" 14:43:19 The approach s more: you need to define a discriminator in terms of its features, and not the features in terms of the discriminators... at least I got no input on that direction so far. and I suggested to start from the other end last time. 14:43:20 Leora: In last f2f we found that this is not sufficient. Example: Various action languages. 14:43:28 q+ 14:43:38 ... believed that was consensus then. 14:44:02 q+ 14:44:27 Allen: About chicken and egg problem. E.g. production rules, parts of which can correspond to derivation rules. 14:44:49 ... Not impossible that there are such overlaps. 14:45:00 ... E.g. using Jess for pure deduction. 14:45:23 ... What Axel shows is that you gain something on the Ruleset level. 14:45:43 Chris: Yes, but in parallel we need Dialect level. 14:46:46 Hassan: Agree with both. No hope that there is a complete characterization. Only approximations are possible. Stepwise. Then draw a lin: E.g. "This is fine enough for our purpose." 14:47:41 ... RIFRAF is a bridge, people can agree, and then exchange. 14:47:42 +1 to hassan 14:47:48 q- 14:47:49 ... with RIF. 14:48:09 Axel: Wanted to get started with Base Ontology. 14:48:12 q+ 14:48:48 q- 14:48:48 ... Two outcomes: Define discrimintors by features. Continuing this exercise by inventing new features. 14:48:58 People can give feedback. 14:49:49 ... Second: Was meant to lay the groundwork for others to build on. Iterations on top, to see what comes out. 14:50:22 ... Obviously not do it alone. Re-confirm commitment? 14:50:31 q? 14:50:37 ack axel 14:50:45 Shall I repeat, I think I was alking to fast :-) 14:51:32 Dave: Different grain sizes of dialects. Originally small number of large dialects. Today's examples much more fine-grained. 14:52:07 ... Might have a mechanism to avoid hundreds of dialects (by merging some?). 14:52:16 +1 to Dave on combining BU with TD classification (has been my point all along BTW)... 14:52:34 just short: I need to drop out at 4 14:52:52 Chris: We still need more coarse-grained dialects. But Axel's fine-grained ones are still useful. 14:53:13 (Chris pls use your mike) 14:53:40 ... You can find that a given Ruleset fits into a dialect using fine-grained discriminators. 14:54:02 fine 14:54:09 no objection against what Chris said. As I said, it was one possible proposal, and I am definitly open to other proposals. 14:54:10 nothing 14:54:31 q? 14:54:57 I agree that all these efforts should go concurrently 14:55:06 Chris: Hassan and Leora, do you agree with this disctinction? 14:55:14 Hassan and Leora: Yes. 14:55:45 Chris: Has obvious use for interchange. 14:56:28 Leora: Questionnaire made assumptions about defining classes, and only asking questions within these classes. 14:56:55 Hassan: Yes, the classes were already defined top-down. 14:57:09 Comment: is the idea that syntax analysis is part of the problem, vs semantic analysis (or rule languages covered by RIF) 14:57:58 ... In beginning Hassan started bottom-up. 14:58:19 (Harold - I did not say that!) 14:58:42 Chris: Bottom-up (starting from specific languages) should still be continued. 14:58:53 Hassan, you can correct the log with s/from/to/ substitution commands. 14:59:01 I originally proposed that we start BU, but everyone preferred TD and we have been doing so up to now! 14:59:03 Christian: PRR metamodel could be read as an ontology for production rules. 14:59:05 it shall be aligned, no doubt. 14:59:15 q+ 14:59:59 Axel, the latest (but not so new) public draft of PRR is linked on the wiki front page 15:00:04 Paul: OMG allow great room to incorporate future other representations. Bear in mind that PRR metamodel didn't provide very many discriminators. 15:00:37 ... Paul would be interested to participate in RIFRAF. 15:00:43 ack axel 15:00:49 Chris: Pick a small set of dialects. 15:01:26 Axel: We should have some actions. How to proceed? Still not sure what to edit. 15:01:47 ... Need to complete this exercise. Others should help. 15:02:04 dropping out! 15:02:12 bye 15:02:21 -Axel_Polleres 15:03:05 Leora: Initially assigned ECA part, later done by Paula. Would prefer ECA. 15:03:22 Chris: Alright, this is your action now. 15:03:51 Allen: Some properties only apply to language level, not ruleset level. 15:03:59 DaveReynolds_ has joined #rif 15:04:16 ... Need to classify properties/discriminators. 15:04:42 Hassan: You as the language designer know the properties, so you can type it into. 15:05:01 ... You fill in values into the discriminators. 15:05:25 Allen: Putting in ontology. 15:05:38 Hassan: Yes, need to ask the right questions. 15:06:01 Allen: syntact-semantic. 15:06:11 Hassan: and pragmatic. 15:06:11 http://www.w3.org/2005/rules/wg/wiki/Rulesystem_Arrangement_Framework 15:07:09 Chris: Drop Frank's action. Ask Paula. Leora moved to section 5. Hassan more in asn06 and XML generation. 15:07:50 Leora: Test cases to point out usefulness, nothing else. 15:08:29 Chris: Will ask Paula, if she wants to continue that action. 15:08:53 ... What is reasonable milestone? 15:09:21 Leora: Useful characterization of action languages. Until some time in April. 15:09:34 Chris: 1st week of April. 15:09:38 Leora: OK. 15:09:48 -Hassan_Ait-Kaci 15:09:54 -Leora_Morgenstern 15:10:02 Allen: Same here: 1st week of April. 15:10:09 BREAK. 15:23:58 Evan has joined #rif 15:40:13 MichaelKifer has joined #rif 15:40:54 scribenik:MichaelKifer 15:41:01 DaveReynolds_ has joined #rif 15:41:27 Discussion of the architecture document 15:41:46 zakim, scribenik:MichaelKifer 15:41:46 I don't understand 'scribenik:MichaelKifer', MichaelKifer 15:43:30 CSMA: time to start thinking on what should go into the arch document. Some stuff from the current core will be moved/copied there 15:43:37 sandro has joined #rif 15:44:44 Dave: maybe the condition language should be in the arch doc 15:44:47 scribenick: MichaelKifer 15:44:57 zakiim, scribenick: MichaelKifer 15:45:14 the first one was fine. there is no confirmation. 15:45:25 RRSAgent, make minutes 15:45:25 I have made the request to generate http://www.w3.org/2007/02/28-rif-minutes.html sandro 15:45:46 Harold: no, only some design principles of the condition language should go to the arch 15:46:21 csma: the arch should be a global view 15:46:47 s/no, only some/well, it would be sufficient if only some/ 15:48:27 csma: should have a list of basic concepts where the details will be filled in by different dialects 15:48:59 +Hassan_Ait-Kaci 15:49:31 Sandro, I would say the Core consists of the Condition language as a foundation and the Horn language as one extension. 15:49:59 DaveR: the arch will contain many features outside of the core. For instance: negation. 15:50:47 Other extensions, e.g. Production Rules, can be built on top of the Condition language, also reusing aspects of the Horn language. 15:51:17 csma: yeah (hopefully the arch will be a repository for reusable components) 15:52:11 Jos: what does it mean to include a spec in the arch doc? This either makes no sense or will lead to huge duplication 15:52:12 Duplication...... 15:52:47 Arch and Library -- maybe different documents. 15:52:59 Jos, maybe the Architecture chapter/document could be based on RIFRAF, thus give a framework to classify RIF language features, not give their complete semantics (even less their syntax). 15:53:50 csma: duplication might be avoided (but doesn't quite know how to achieve) 15:53:51 s/their complete semantics (even less their syntax)/the complete semantics (even less syntax) of dialects. 15:54:31 mdean has joined #rif 15:55:34 Harold: should list discriminators and help the outsider to navigate RIF waters 15:55:52 The title uses "The RIF", Isn't that a violation of our convention? 15:57:15 Dave: arch - a central repository of concepts where dialects will point to for definitions 15:59:00 Sandro: will this make the core a 1p doc? 15:59:46 csma/sandro: discussion of what is "reusable" 16:00:22 'Reusers' of a base dialect such as the Condition language who layer other dialects on top could propose refinements/extension to the base dialect that they think could also help other layerings on top of the base dialect. 16:01:17 Sandro: should every little thing go to the arch doc? Eg, some piece from a fuzzy rule dialect? 16:01:46 DaveR: no, only the main parts are of interest in the arch doc. 16:01:58 is the section titled "text cases" supposed to be "test cases"? 16:02:00 If indeed the propose refinements/extensions are helpful synergetically across 'side by side' layers, they should move into the base dialects. 16:05:13 mike? 16:05:49 Sandro: but components shuold be able to become entries in the library (or multiple libraries) without changing them. 16:06:32 Can you hear csma? 16:08:51 +Leora_Morgenstern 16:09:05 DaveR/CSMA: semantics of some concepts (eg, AND/OR) could be defined in the arch document. Other things might be harder to make reusable (eg, negation as failure) 16:11:34 MK: this might make the docs unreadable (full of pointers) 16:12:19 DaveR: instead of pointers we could use cut/paste to include the relevant pieces into dialect descriptions 16:14:07 Dave, the initial Condition language was internally layered in a way similar to what you just mentioned, namely from A1 to A.5 of the Extensible Design: http://www.w3.org/2005/rules/wg/wiki/Extensible_Design 16:17:47 Michael, I agree to what you say: We should not set the bar too high, but talk about principles, eg. on how to extend FOL with NAF. 16:17:50 Sandro: I'm unclear about how XML namespaces should line up with the dialects/components, etc. rif: or rifcore+rifpr, etc....? 16:20:15 ACTION: Harold to experiment with modularization of Condition library 16:20:15 Created ACTION-253 - Experiment with modularization of Condition library [on Harold Boley - due 2007-03-07]. 16:20:32 MK: we are possibly trying to set the bar too high for the arch doc. This doc should contain the general principles that go into the design of RIF (eg, how to go from FOL semantics to nonmon semantics of LP style rule languages. 16:21:19 +1 to Dave: the Data model and the Rule model are orthogonal... 16:23:12 csma: Issue: what are the deployment models? What does it mean to implement rif? Test cases? 16:23:40 csma: extensibility: given a dialect, how to extend it? 16:24:04 csms: backward/forward compatibility issues 16:24:32 bye everyone - I need to attend another meeting. Hope you all enjoyed RIFing at MITRE! 16:24:36 csma: what about lub(two dialects) 16:24:58 lub = least upper bound 16:26:03 csms: architectural principles behind the syntax. How to extend the semantics of a dialect? 16:26:35 Jos: where are OWL and RDF in the arch picture? 16:27:38 what was that? 16:27:57 That was clapping for Allen and Deborah. Thank you from us on the phone too! 16:31:17 csma: should we not emphasize owl but interoperation with other KB formalisms (eg, common logic)? 16:31:51 Harold: ontologies play a special role (ie, OWL/RDF are more important. 16:35:07 Harold: what about rule/ontology compatibility in the arch doc? 16:40:59 josb has left #rif 16:41:02 josb has joined #rif 16:41:08 ACTION: mkifer to start semantics section of Arch 16:41:08 Created ACTION-254 - Start semantics section of Arch [on Michael Kifer - due 2007-03-07]. 16:41:27 ACTION: sandro to review extensibility section of Arch 16:41:27 Created ACTION-255 - Review extensibility section of Arch [on Sandro Hawke - due 2007-03-07]. 16:41:50 ACTION: csma to revise Conformance section of Arch 16:41:50 Sorry, couldn't find user - csma 16:41:58 ACTION: christian to revise Conformance section of Arch 16:41:58 Created ACTION-256 - Revise Conformance section of Arch [on Christian de Sainte Marie - due 2007-03-07]. 16:42:52 ACTION: christian to revise Conformance section of Arch 16:42:52 Created ACTION-257 - Revise Conformance section of Arch [on Christian de Sainte Marie - due 2007-03-07]. 16:44:41 csma: deployment of rules concept: party A sends rule set R to party B. What data sets should be used by the different copies of R. 16:45:42 csma: any takers to think about rule deployment? 16:46:01 http://www.w3.org/TR/owl-test/ 16:47:54 DaveR: test cases' purpose is to document the various decisions and to differentiate between rule sets that are compliant with those decisions and those that do not 16:49:57 DaveR: example of a test case for round-tripping: should be able to test if one's application conforms to the round-tripping decision. 16:51:23 ACTION: DaveReynolds to put in a short entry under Test Cases, outlining the issues 16:51:23 Sorry, couldn't find user - DaveReynolds 16:51:31 ACTION: Dave to put in a short entry under Test Cases, outlining the issues 16:51:32 Created ACTION-258 - Put in a short entry under Test Cases, outlining the issues [on Dave Reynolds - due 2007-03-07]. 16:52:21 ACTION: Jos to start OWL/RDF compatibility section of Arch document 16:52:21 Sorry, amibiguous username (more than one match) - Jos 16:52:21 Try using a different identifier, such as family name or username (eg. jdebruij, jderoo) 16:52:29 csma: missing section: how is RIF positions wrt OWL and other players in the semweb domain. 16:52:40 ACTION: jdebruij to start OWL/RDF compatibility section of Arch document 16:52:40 Created ACTION-259 - Start OWL/RDF compatibility section of Arch document [on Jos de Bruijn - due 2007-03-07]. 16:52:55 ACTION: Dave to put in a short entry under Data Sets, outlining the issues 16:52:55 Created ACTION-260 - Put in a short entry under Data Sets, outlining the issues [on Dave Reynolds - due 2007-03-07]. 16:54:51 16:59:02 Topic: MITRE Demo 16:59:33 zakim, who is on the phone? 16:59:39 On the phone I see meeting_room, Hassan_Ait-Kaci, Leora_Morgenstern 17:01:05 LeoraM has joined #rif 17:01:58 -Hassan_Ait-Kaci 17:02:02 Topic: Lunch 17:02:04 -Leora_Morgenstern 17:49:33 I need to leave - so I'll skip the demos (hopefully, Sandro will write more about his stuff). Thanks for putting up with my whining about mikes and such... Have a safe trip back. -hak 17:50:25 Thanks, Hassan! 17:50:29 Enjoy. 17:52:47 DaveReynolds_ has joined #rif 18:01:09 zakim, who is on the phone? 18:01:09 On the phone I see meeting_room 18:36:17 http://owl.man.ac.uk/hoolet/ 18:52:58 ScribeNick: Deborah 18:54:02 Sandro: can we solve the dichotomy between p(s,o) and rdf(s,p,o) by using the HiLog style. 18:54:14 Topic: RIF-RDF Compatibility 18:56:16 Harold: The HiLog style allows one to query over predicates. 18:57:09 josb: Do we want to allow/require querying over predicates in the Core? 18:57:56 ChrisW: Would you write rules to express the semantics of rdf and want them to be expressible in RIF? 18:58:36 josb: You may not express the rules, but any reasoner that uses rdf rules would have to take the semantics of rdf into account. 19:01:16 DaveReynolds: We do have a use case for sharing rules that process rdf. 19:01:38 HiLog Example: "Show all relationships between John and Mary" -- RPS: ?R(John Mary) -- XML: R John Mary . 19:02:08 DaveReynolds: May need to process over the predicate in order to translate/operate over the rules. 19:03:07 DaveReynolds: You may be using rules to do data mapping and want to carry over all properties' values. 19:04:09 josb: Has a different use case, where you want to make use of the RDF rules when integrating data. 19:04:49 ChrisW: There are two different solutions to josb's case: embedded translation, or translating your RDF into rules. 19:05:17 ChrisW: It's easy to imagine doing that for a small set of rules like RDF but harder for OWL. 19:07:12 "translation" (like hoolet) vs "embedding" (like surnia) 19:07:28 DaveReynolds: But people are writing rules for the processing of RDF data that are in effect an extension of RDF. 19:09:08 josb: Must also think about OWL compatibility, and the designers chose to use RDF(S). 19:09:08 Chris: I am confident that some day we'll have a dialect that lets you qualitify over predicates 19:10:37 josb: May need different strategies for the different flavors of OWL. 19:11:12 mdean: In applications, the flavors are not treated as separately as you may think. 19:12:39 ChrisW: There is an actual incompatibility between OWL-DL and Full wrt the definition of ObjectProperty. 19:14:14 Another reason for RIF to look more carefully into OWL soon is that the OWL community is moving on, too -- OWL 1.1: http://owl1_1.cs.manchester.ac.uk/ 19:14:38 ChrisW: In the two strategies, embedding vs. translation, embeding has some advantage for round-tripping but disadvantage for size of what is exchanged. 19:15:10 Harold: We might state what we consider advantages/disadvantages of embedding vs. translation. 19:15:33 Harold: See also OWL 1.1 spec. 19:16:03 ChrisW: Not clear we have a prior position on including quantification over predicates in the Core. 19:17:31 MichaelKifer: The problem with including quantification over predicates is that there are languages that don't support it. 19:17:39 Sandro: I'd sure love hilog in the core from an RDF perspective --- because __triple(s,p,o) is an ugly RDF ghetto, and p(s,o) doesn't support embedding. 19:19:03 josb: Could put constructs for RDF triples in the rules (besides the literals) so we could cover RDF without representing it as a binary predicate. 19:19:35 MichaelKifer: Since we're going to introduce slots, could use that. 19:19:47 ChrisW: Need to define 'slots'. 19:20:09 "named arguments to predicates" 19:20:11 MichaelKifer: "Named arguments to predicates" 19:20:37 josb: That would be exactly equivalent to RDF triples. 19:22:08 josb writes on white board to illustrate: s p o 'equivalent to' s[p ->>o] 19:23:10 Chris: so you're not talking about named arguments to predicates, you're talking about structured objects -- objects that have attributes or slots with values. 19:23:14 ChrisW: By 'slots' we are NOT talking about keyword ('named) arguments to predicates. Rather, we are talking about structured objects that can bind to rules. 19:23:47 ChrisW: So if an object has something true of it, and if p is a binary predicate, then how do you write a rule about that predicate? 19:24:21 josb writes on board to show how, in that approach, you would write a rule that quantifies over the predicate: 19:25:20 x{p->>q]<-x[p->>z], z[p->>q]. 19:25:41 If we write _triple(s,p,o) as _triple(p,s,o) we can easily generalize it to the N-ary predicate versuib _ntuple(p,a1,a2,a3,...,aN). The '_ntuple' dummy predicate has been called 'apply' in Warren's classical paper "Higher-Order Extensions of Prolog -- Are they Needed?". apply(p,a1,a2,a3,...,aN) can be used to reduce the semantics of the syntactically higher-order sugared p(a1,a2,a3,...,aN) to first-order. 19:26:04 ChrisW: Does this create a different annotation for binary predicates than for other predicates? 19:27:52 josb: No, 'p' there (above) is not a predicate; it's an object. 19:28:12 MichaelKifer: It has an interpretation as a predicate but also as an object. 19:29:48 josb: In RDF, 'p' is an object, not a predicate. 19:30:05 s/N-ary predicate versuib/N-ary predicate '_ntuple' as in/ 19:30:22 MichaelKifer: Slotted syntax is disjoint from predicate syntax, but they can be used together in rules. 19:30:47 josb: May depend on restrictions of the dialect. 19:32:26 We return to the question of whether RIF will have support for RDF in the Core. 19:33:38 josb: s[p->>o] is equivalent to _triple(s,p,o). 19:34:14 sandro: What would we call it in the abstract syntax? 19:34:22 josb: It's called a 'molecule'. 19:34:55 Harold: It's called a 'molecule' in F-Logic. 19:35:18 csma: We don't need to import all of F-Logic into the Core. 19:35:23 Confirmed by MichaelKifer. 19:35:59 MichaelKifer: But he had raised an issue about the typing of the components of these molecules. 19:37:10 josb (illustrating in writing): S[ Af.type ->>P ]. (missing symbols) would be needed, also. 19:37:49 ChrisW: With the exception of quantification over predicates, there is no problem with handling RDF. 19:38:15 MichaelKifer: With the [molecular] approach, the quantification problem goes away. 19:38:30 josb: And with signatures for typing. 19:39:30 DaveReynolds: You don't want an [RDF] implemeter to have had to have written RDFS in order to make use of RIF. 19:40:11 Sandro: so would RIF Core include RDFS entailment? 19:40:22 DaveReynolds: Want RIF to handle rules that work over RDF data without having the RDF semantics with their data. 19:40:31 Next topic: RIF Support for OWL 19:41:28 Harold: Features of OWL not included in RIF Core include classical negation, disjunction, and existential quantification. 19:42:26 josb: For OWL Full, which is a direct extension of RDF, you can make use of the approach already described. 19:42:41 csma: See Hassan's paper, section on OWL-DL. 19:43:04 josb: Might be tricky to combine the [molecular] approach with OWL DL. 19:43:39 because OWL DL puts restrictions on the kinds of triples you can write. Also, the unary and binary predicates are reallly predicates and not objects, in OWL DL. 19:44:38 josb: For OWL DL, you would use a RIF dialect where you had disjointness bewteen predicates of different arity; then have different approaches for each. 19:44:51 Harold: How does this fit with multisorted approach. 19:46:06 josb: The molecule approach seems to give us a good approach to OWL. 19:46:33 There is a problem with having RDF data sets combined together with OWL DL. 19:47:06 We don't want to break the interoperability by having to treat binary predicates and then rdf properties differently. 19:47:12 Adjouned. 19:48:22 s/Harold: Features of OWL not included in RIF Core include classical negation, disjunction, and existential quantification/Harold: Of the OWL features Jos mentions as not included in RIF Core (include classical negation, disjunction, and existential quantification) actually disjunction and existential quantification are partially present in the condition language and the body of rules 19:48:51 rrsagent, make minutes 19:48:52 I have made the request to generate http://www.w3.org/2007/02/28-rif-minutes.html ChrisW 19:48:54