Re: Notation3 Community Group Report Release

I have not been following the N3 community group, but regarding builtins 
did you consider the RIF collection? [1].

Due to timing of various working groups at the time they were unable to 
harmonize completely between the xpath, sparql, and RIF built-in 
definitions, but in my experience the RIF collection was the most 
extensive (about 10 years ago).

Regards,
--Paul

[1] https://www.w3.org/TR/2013/REC-rif-dtb-20130205/

On 7/7/23 09:09, Doerthe Arndt wrote:
> Dear Ivan,
>
> Just one quick answer:
>
> I am not even sure whether the built-ins are always required (most 
> likely not), but they are in the files we shared to make the reasoning 
> performant. An example for eq-diff3 without built-ins (apart from 
> rdf:first and rdf:rest which you could understand as built in) is 
> here: https://n3-editor.herokuapp.com/n3/editor/s/Fa712hqP
>
> But your point is interesting: the built-ins should relate to other 
> standards. So far we are trying to find out which built-ins we need to 
> fully implement SPARQL with all its filter functions, that goes into 
> the same direction. We will certainly keep your comment in mind.
>
> Kind regards,
> Dörthe
>
>
>> Am 07.07.2023 um 15:14 schrieb Ivan Herman <ivan@w3.org>:
>>
>> Doerthe, William,
>>
>> thank you both for the answers. If I understand the references right 
>> (I cannot get behind the paywall of Springer for the some of them) 
>> the implementation of features like property chain axioms rely on 
>> suitable built-ins; I expected that, although I was not sure (I do 
>> not have experience with n3 usage beyond the documentation).
>>
>> Which raises one more question to me, looking ahead to a possible 
>> full standardization path of n3 at W3C: if we ever get to that point, 
>> it may look much better if the final standard on built-ins included 
>> the definition of those that are necessary to implement OWL 2 RL (I 
>> do not know about OWL 2 EL). The relationship among the different 
>> technologies published by W3C is always a question, and this may come 
>> up during a formal review, for example. Just a thought…
>>
>> Thanks!
>>
>> Ivan
>>
>>> On 7 Jul 2023, at 14:27, Doerthe Arndt <doerthe.arndt@tu-dresden.de> 
>>> wrote:
>>>
>>> Dear all,
>>>
>>> The OWL-RL rules are for example available for at the EYE repository 
>>> (note that these rules are the rules from the OWL2 spec inheriting 
>>> the problems these might have): 
>>> https://eulersharp.sourceforge.net/2003/03swap/eye-owl2.html
>>>
>>> Some of the rules use built-in functions like for example eq-diff3 
>>> which Ivan mentioned below: 
>>> https://eulersharp.sourceforge.net/2003/03swap/owl-distinctMembers.html
>>>
>>> In the past, I used some optimizations to make the reasoning faster 
>>> (paper: 
>>> https://link.springer.com/chapter/10.1007/978-3-319-33245-1_10), if 
>>> you are interested, I can also provide the rules.
>>>
>>> I am sure that N3 can also cover OWL-EL (there is for example this 
>>> nice tutorial where this has been implemented in existential rules 
>>> https://iccl.inf.tu-dresden.de/web/Rules_ECAI_Tutorial_2020/en). N3 
>>> supports existential rules, so OWL-EL is possible, but we do not 
>>> have not even the basic rules yet and no optimization of any kind.
>>>
>>> To also answer the questions:
>>>
>>> 1. SPARQL works over the output of both kinds of reasoning, all it 
>>> needs is an RDF graph. However, in N3 (at least with EYE and Cwm, 
>>> most likely also with jen3) you can also specify filter rules or 
>>> queries. You basically mark certain rules as queries and the 
>>> reasoning run will give you only the results of these particular 
>>> rules as output. In EYE you can even produce csv with that. As N3 
>>> supports many built-ins, such rules might be an alternative for 
>>> queries. We are also currently working on the translation from 
>>> SRARQL to N3, but this is work in progress.
>>>
>>> 2. N3 follows the open world assumption, but it allows scoped 
>>> negation as failure. More concretely that means that you can ask the 
>>> reasoner whether something can be derived from  the facts and rules 
>>> you gave as input. One of the predicates using a scope is 
>>> log:collectAlIn (see 
>>> https://w3c.github.io/N3/reports/20230703/builtins.html#log:collectAllIn). 
>>> If you’d like to use the predicate to express negation, use an empty 
>>> list as argument (example: 
>>> https://n3-editor.herokuapp.com/n3/editor/s/9J0rKNEm). Feel free to 
>>> ask for further details if you are interested :)
>>>
>>> Kind regards,
>>> Dörthe
>>>
>>>
>>>> Am 06.07.2023 um 18:19 schrieb Christopher Yocum <cyocum@gmail.com>:
>>>>
>>>> Dear Ivan and William,
>>>>
>>>> Thank you very much for your explanations.  This was very helpful.  I
>>>> am intrigued by the differences.
>>>>
>>>> I tend to use OntoText GraphDB with OWL2 RL with my data as I have an
>>>> ontology which works for my use case (Medieval Irish Genealogies).  I
>>>> assume that SPARQL will work over both?  One thing about OWL2 that is
>>>> sometimes difficult to grasp is the Open World Assumption. Does N3 use
>>>> "Open World" or is it a "Closed World"?
>>>>
>>>> Thank you again for your time.
>>>>
>>>> All the best,
>>>> Chris
>>>>
>>>> On Thu, Jul 6, 2023 at 4:23 PM Ivan Herman <ivan@w3.org> wrote:
>>>>>
>>>>> William, (and Christopher)
>>>>>
>>>>> just to add one thing to the comparison.
>>>>>
>>>>> Where N3 and OWL 2 "meet" in some ways is the RL profile of OWL 
>>>>> 2[1]. This is a "subset" of OWL 2 that can be implemented using 
>>>>> rules. Actually, the spec includes the list of rules[2] that can 
>>>>> be implemented, e.g., by a forward chaining engine, to offer an 
>>>>> OWL 2 reasoner. I think it would be worthwhile to add a comparison 
>>>>> of N3 with OWL 2 RL in the document, b.t.w.
>>>>>
>>>>> Cheers
>>>>>
>>>>> Ivan
>>>>>
>>>>> (At a first glance, the translation most of the rules in [2] into 
>>>>> N3 looks trivial, ie, it is possible to create an N3 "graph" that 
>>>>> can be used as a set of OWL 2 RL axioms. There are some rules 
>>>>> where, I must admit, I do not see at first glance how to make this 
>>>>> translation in general, like eq-diff3, prp-spo2; these all are not 
>>>>> "rules" in [2] but more a family or rules for lists.)
>>>>>
>>>>> [1] https://www.w3.org/TR/owl2-profiles/#OWL_2_RL
>>>>> [2] 
>>>>> https://www.w3.org/TR/owl2-profiles/#Reasoning_in_OWL_2_RL_and_RDF_Graphs_using_Rules
>>>>>
>>>>> On 6 Jul 2023, at 16:11, William Van Woensel 
>>>>> <william.vanwoensel@gmail.com> wrote:
>>>>>
>>>>> Thanks for your question. (The report does have a section on 
>>>>> relations with other languages, but it does not include OWL2!)
>>>>>
>>>>> Both are declarative formalisms for describing your domain or 
>>>>> problem - you can then let a reasoner fill in the blanks or try 
>>>>> and solve the problem. But, they differ in the kind of logic and 
>>>>> reasoning they apply. Their usefulness depends on your use case, 
>>>>> and, to some extent, your personal preferences.
>>>>>
>>>>> TL;DR
>>>>> OWL2 is related to Description Logics - you define class 
>>>>> expressions in terms of constraints on their individuals, and then 
>>>>> use a reasoner (such as hermit, pellet,...) to find 
>>>>> inconsistencies, classify individuals (put them under the right 
>>>>> class), or determine subsumption (subclass relations). Notation3 
>>>>> (N3) is a rule language - you can define logical implications, 
>>>>> basically if-then rules, which state what can be inferred from 
>>>>> other triples. A reasoner (such as eye, cwm or jen3) can then 
>>>>> generate all applicable inferences given a set of triples. In 
>>>>> addition, N3 has builtins for math, string, time and other 
>>>>> operations, as well as builtins for scoped negation as failure (to 
>>>>> "close" the world to an extent).
>>>>>
>>>>> Longer answer: The question is complex and has multiple aspects. 
>>>>> Since you asked from a developer point of view I try to emphasise 
>>>>> that aspect.
>>>>>
>>>>> OWL2 DL is based on description logics, which is a decidable 
>>>>> fragment of first order logic. Decidability is a big advantage, 
>>>>> but it also comes with certain restrictions on the things you can 
>>>>> and can’t express. Intuitively, you rather think about classes and 
>>>>> subclasses in which you can or cannot put individuals. OWL2 allows 
>>>>> disjunctions (“or”) which are only partly supported by rule-based 
>>>>> reasoning. If you want to add rules to that “class world", you can 
>>>>> use SWRL.
>>>>>
>>>>> N3 is a rule language for the Web. That means you can directly 
>>>>> state which triples should be derived by which other triples. As 
>>>>> N3 allows you to write rules introducing new blank nodes, we know 
>>>>> that N3 - even without any built-ins or exotic patterns - is not 
>>>>> decidable, because logically, we are dealing with existential 
>>>>> rules. This, however, is in most practical cases a rather 
>>>>> theoretical problem.
>>>>>
>>>>> That said, both OWL and N3 reasoners will sometimes need to 
>>>>> capitulate and report a time-out for some corner cases.
>>>>>
>>>>> Hope that clarifies matters.
>>>>>
>>>>>
>>>>> William & Doerthe
>>>>>
>>>>> On Jul 5, 2023, at 3:00 PM, Christopher Yocum <cyocum@gmail.com> 
>>>>> wrote:
>>>>>
>>>>> Hi,
>>>>>
>>>>> This seemed interesting so I went to have a look at it.  After reading
>>>>> a good part of the primer, I am wondering what the difference between
>>>>> N3 and OWL2 are and why I would choose one over the other or if they
>>>>> are complementary, how they relate to each other?  Is there a resource
>>>>> that covers this for the "middle of the road" developer? I did a quick
>>>>> Google but I am not coming up with anything that might help
>>>>> immediately.
>>>>>
>>>>> Thanks and all the best,
>>>>> Chris
>>>>>
>>>>> On Wed, Jul 5, 2023 at 6:12 AM Ivan Herman <ivan@w3.org> wrote:
>>>>>
>>>>>
>>>>> Putting my W3C staff member's hat on… As Doerthe says below, N3 is 
>>>>> not just a minor extension to RDF 1.2, so adding it now to the RDF 
>>>>> Star WG's work would go beyond the charter of that WG. I believe 
>>>>> it would be more appropriate for the N3 Community Group to prepare 
>>>>> itself to propose a bona fide Working Group charter that would be 
>>>>> scheduled to kick in once RDF 1.2 is properly closed. It will then 
>>>>> have to go through the usual hooplas at W3C to get the charter 
>>>>> (hopefully) accepted by the W3C membership and do the rest of the 
>>>>> work to turn it into a formal Recommendation.
>>>>>
>>>>> Hans, this is not a dumb suggestion at all.
>>>>>
>>>>> Cheers
>>>>>
>>>>> Ivan
>>>>>
>>>>> On 4 Jul 2023, at 14:04, Doerthe Arndt 
>>>>> <doerthe.arndt@tu-dresden.de> wrote:
>>>>>
>>>>> Dear Hans,
>>>>>
>>>>> It is a very good idea to combine efforts on N3 and RDF 1.2, but I 
>>>>> am afraid that N3 is too complex to be added directly to RDF 1.2. 
>>>>> More concrete: N3 allows the use of graphs as terms just like 
>>>>> RDF-star supports triples as terms. The latter already causes a 
>>>>> lot of discussions since different potential users (naturally) 
>>>>> have different expectations. I guess a more complex construct of 
>>>>> similar nature will even create more tension.
>>>>>
>>>>> Therefore, the N3 working group plans to wait for the outcome of 
>>>>> RDF 1.2 to then incorporate the (possible) changes of RDF to N3. 
>>>>> Note that some reasoners like for example EYE 
>>>>> (https://github.com/eyereasoner/eye) already support RDF-star. So 
>>>>> far, I do not see major problems if we want to include RDF-star to 
>>>>> N3 (of course that will also depend on the semantics chosen, EYE 
>>>>> currently follows the community group report).
>>>>>
>>>>> Kind regards,
>>>>> Dörthe
>>>>>
>>>>>
>>>>>
>>>>> Am 04.07.2023 um 10:16 schrieb hans.teijgeler@quicknet.nl:
>>>>>
>>>>> Is it a dumb suggestion to combine this N3 effort with the earlier 
>>>>> reported RDF 1.2 one, in order to avoid divergence?
>>>>>
>>>>> -----Original Message-----
>>>>> From: David Booth <david@dbooth.org>
>>>>> Sent: Monday, 3 July 2023 21:11
>>>>> To: semantic-web@w3.org
>>>>> Subject: Re: Notation3 Community Group Report Release
>>>>>
>>>>> On 7/3/23 13:29, William Van Woensel wrote:
>>>>>
>>>>> We are happy to inform you that the first Notation3 Community Group
>>>>> Report has been released: https://w3c.github.io/N3/spec/
>>>>> <https://w3c.github.io/N3/spec/>
>>>>>
>>>>>
>>>>> Awesome!   Great work!
>>>>>
>>>>> Thanks,
>>>>> David Booth
>>>>>
>>>>>
>>>>>
>>>>> Notation3 (also known as N3) is an assertion and logic language that
>>>>> is a superset of Turtle, featuring logical implications (rules), graph
>>>>> terms, and builtins ranging from datatype operations to accessing
>>>>> online knowledge and performing scoped negation as failure.
>>>>>
>>>>> We also created an educational resource as a lightweight introduction
>>>>> to
>>>>> Notation3 (which also lists currently available resources):
>>>>> https://notation3.org/ <https://notation3.org/>
>>>>>
>>>>> We invite you to submit any feedback or issues to our GitHub page:
>>>>> https://github.com/w3c/N3 <https://github.com/w3c/N3>
>>>>>
>>>>>
>>>>> Kind regards,
>>>>>
>>>>> W3C N3 CG Group
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> ----
>>>>> Ivan Herman, W3C
>>>>> Home: http://www.w3.org/People/Ivan/
>>>>> mobile: +33 6 52 46 00 43
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> ----
>>>>> Ivan Herman, W3C
>>>>> Home: http://www.w3.org/People/Ivan/
>>>>> mobile: +33 6 52 46 00 43
>>>>>
>>>>>
>>>
>>
>>
>> ----
>> Ivan Herman, W3C
>> Home: http://www.w3.org/People/Ivan/
>> mobile: +33 6 52 46 00 43
>>
>>
>