- From: Wouter Beek <w.g.j.beek@vu.nl>
- Date: Sat, 21 May 2016 18:51:21 +0200
- To: Nathan Rixham <nathan@webr3.org>
- CC: Simon Spero <sesuncedu@gmail.com>, Harry Halpin <hhalpin@ibiblio.org>, Melvin Carvalho <melvincarvalho@gmail.com>, Pat Hayes <phayes@ihmc.us>, "Phil Archer" <phila@w3.org>, Semantic Web IG <semantic-web@w3.org>
- Message-ID: <CAEh2WcNfXguziWKMOm8O1bYzU5W5ym6n=Zx61dSTc9KD8Sbd6g@mail.gmail.com>
Hi, >From the comments so far it seems that most are in favor of a data publisher adding explicit relations between [1] and [2], whether they be `owl:sameAs' or some variant. [1] http://dbpedia.org/resource/Category:Semantics [2] https://dbpedia.org/resource/Category:Semantics I want to point out that a similar issue has already been around for as long as the SW exists: IRIs that differ only in terms of escaping are different SW names even though they denote the same Web location. In practice I do not always see a data publisher make explicit (`owl:sameAs') assertions between [3] and [4] (although some do, I've seen them in LOD Laundromat). [3] http://dbpedia.org/resource/Category:Semantics [4] http://dbpedia.org/resource/Category%3ASemantics --- Cheers, Wouter. On Sat, May 21, 2016 at 5:50 PM, Nathan Rixham <nathan@webr3.org> wrote: > > On the other hand, there is no specific reason not to continue using > http: IRIs as names > > It seems perfectly rational for somebody to want to say refer to #me as > https://example.com/Alice#me rather than http://example.com/Alice#me > please ( con:preferredURI ). Likewise for any name. More so if for > technical or financial reasons they cannot eternally support their old name > in a linked-data friendly way. Let's say HostGator or GoDaddy migrate all > shared hosting accounts to https supporting 301s only for 6 months only. > > > owl:sameAs > > x:canonical rdfs:subPropertyOf owl:sameAs . > x:canonical rdfs:subPropertyOf ??? . > > What to use for ???, where ??? is like > http://www.w3.org/2000/10/swap/pim/contact#preferredURI but for any name. > > Ultimately I guess we're just looking for a property that when encountered > informs a developer or system to perform a graph update and replace aaa > with bbb. > > > On Sat, May 21, 2016 at 4:16 PM, Simon Spero <sesuncedu@gmail.com> wrote: > >> sameAs is correct, though under under the OWL Direct Semantics, it may >> not give all the desirable entailments if the IRI denotes a Class or >> *Property. Using equivalentClass / equivalentProperty axioms gives desired >> result. >> >> On the other hand, there is no specific reason not to continue using >> http: IRIs as names, and using a different protocol if those names are >> converted to locators. >> >> Simon >> >> >> >> On Sat, May 21, 2016, 10:40 AM Nathan Rixham <nathan@webr3.org> wrote: >> >>> Why not owl:sameas? Is it technically incorrect? >>> >>> If it's the correct property to use and widely understood + supported, >>> saying it's been used incorrectly previously doesn't hold much weight as an >>> argument against using it correctly to solve a web scale real world problem >>> simply. >>> On 21 May 2016 2:28 pm, "Simon Spero" <sesuncedu@gmail.com> wrote: >>> >>>> There is no necessary between an IRI used in any position in an RDF >>>> triple, and any #$InformationBearingObject that may be returned as a result >>>> of interpreting the lexical form of such an IRI as a set of procedural >>>> directives. >>>> >>>> There is thus no reason why Stigmergic Web applications cannot >>>> interpret these lexical forms such that they perform different actions, >>>> with no required changes anywhere else. >>>> >>>> Meet the new sameAs, same as the old sameAs. >>>> >>>> Simon >>>> On May 21, 2016 12:53 AM, "Harry Halpin" <hhalpin@ibiblio.org> wrote: >>>> >>>>> Given that the Semantic Web use of HTTP URIs basically means that any >>>>> use of 'follow your nose' is easily subverted by anyone with access to the >>>>> raw HTTP stream, we should just update the Semantic Web specs and reasoners >>>>> so that TLS is enforced by default and HTTP = HTTP(S). >>>>> >>>>> While it is true that some normal web-pages *can* serve different >>>>> content at TLS than non-TLS, it's currently considered pathological. >>>>> >>>>> If the Semantic Web doesn't gracefully deal with the upgrade from HTTP >>>>> to TLS, it will date itself quite quickly and will not be usable for any >>>>> real-world usage (notice almost all major sites now are moving to TLS) >>>>> outside of enterprise use within a firewall or usages where there's no >>>>> 'follow your nose' effort. In the latter case, I'm not sure if using HTTP >>>>> URIs makes sense to begin with. >>>>> >>>>> Note that the upgrade should be relatively cost-free, see the "Let's >>>>> Encrypt" effort for free TLS certs. >>>>> >>>>> On Fri, May 20, 2016 at 6:04 PM, Pat Hayes <phayes@ihmc.us> wrote: >>>>> >>>>>> >>>>>> On May 20, 2016, at 5:02 PM, Nathan Rixham <nathan@webr3.org> wrote: >>>>>> >>>>>> .... >>>>>> An x:alias predicate which asserts that one name (IRI) is an alias of >>>>>> another name (IRI) would be very useful. <a#b> x:alias <c#d> . >>>>>> >>>>>> An x:canonical predicate which asserts <a#b> x:alias <c#d> . and that >>>>>> <a#b> is the preferred IRI more useful still. >>>>>> >>>>>> >>>>>> Just an observation - it may be that practical needs override >>>>>> formality - but this is not legal according to the RDF semantics. The truth >>>>>> of a triple aaa R bbb depends only on what the IRIs in the triple, in >>>>>> particular aaa and bbb, *denote*, not on their syntactic form. So x:alias >>>>>> would have the same semantics as owl:sameAs (and we all know what happened >>>>>> to *that* when it got out into the wide world.) >>>>>> >>>>>> We could sneak around this by declaring (contrary to the normative >>>>>> semantics, but still...) that x:alias is a new kind of property, one that >>>>>> quotes its arguments and is therefore referentially opaque. There would >>>>>> have been a time when I would have opposed this idea with some vigor, but >>>>>> age has mellowed me. And the internal semantic coherence of the Web can >>>>>> hardly get worse than it is already, so what the hell. Just be ready for >>>>>> the truly awful muddle that will arise when x:alias bumps into owl:sameAs >>>>>> and reasoners try to figure out what the consequences might be. >>>>>> >>>>>> A better solution would be to invent, and have everyone adopt[**], a >>>>>> IRI-quoting-IRI convention, something like x:theIRI# , with the semantics >>>>>> that x:theIRI#someOtherIRI always denotes someOtherIRI. (Maybe this would >>>>>> need some clever character-escaping? I leave that to others to work out.) >>>>>> Then x:theIRI#a#b x:alias x:theIRI#c#d would mean what you want to express, >>>>>> above. >>>>>> >>>>>> Pat Hayes >>>>>> >>>>>> [**] There's the rub, of course. >>>>>> >>>>>> >>>>>> Using syntax shortcuts you could add the following triple to the >>>>>> turtle document at https://www.w3.org/1999/02/22-rdf-syntax-ns# >>>>>> >>>>>> rdf: x:canonical <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . >>>>>> >>>>>> Result: >>>>>> <http://www.w3.org/1999/02/22-rdf-syntax-ns#> a owl:Ontology . >>>>>> <https://www.w3.org/1999/02/22-rdf-syntax-ns#> a owl:Ontology . >>>>>> >>>>>> >>>>>> Point 2: >>>>>> >>>>>> Using a 307 redirect for the semantic is nice, but practically click >>>>>> http://www.w3.org/ns/dcat# and you are redirected, refresh and you >>>>>> find the client does use the redirected url for subsequent requests. >>>>>> >>>>>> As a general person or developer search w3.org for dcat and the >>>>>> results are https://www.google.com/search?q=site:w3.org%20dcat - the >>>>>> url listed is the https url. >>>>>> >>>>>> Usage of the https IRIs will enter the web of data ever increasingly, >>>>>> whether people say the http one should be used or not. >>>>>> >>>>>> Point 3: >>>>>> >>>>>> Practically taking a simple real world step like migrating to a CDN >>>>>> will often give http/2+tls thus https IRIs automatically. >>>>>> >>>>>> Test case: >>>>>> >>>>>> Alice has a wordpress/drupal site that publishes RDF automatically. >>>>>> She doesn't know about the RDF. >>>>>> Alice clicks the "free CDN" button in her hosting account. >>>>>> Alice now has https and http IRIs in RDF on both http:// and https:// >>>>>> protocols. >>>>>> >>>>>> Personally I cannot think of anything easier than as best practise >>>>>> adding a single triple to rdf documents when migrating protocols. Anything >>>>>> within the black box will fail and be implemented incorrectly. >>>>>> >>>>>> On Sat, May 21, 2016 at 12:42 AM, Melvin Carvalho < >>>>>> melvincarvalho@gmail.com> wrote: >>>>>> >>>>>>> >>>>>>> >>>>>>> On 20 May 2016 at 20:08, Phil Archer <phila@w3.org> wrote: >>>>>>> >>>>>>>> Not a moan about spam, or a CfP, but an actual discussion point, >>>>>>>> yay! >>>>>>>> >>>>>>>> I've just blogged about our use of HTTPS across www.w3.org which >>>>>>>> raises some questions for this community. Please see >>>>>>>> >>>>>>>> https://www.w3.org/blog/2016/05/https-and-the-semantic-weblinked-data/ >>>>>>> >>>>>>> >>>>>>> On the one hand more security is a nice to have, but on the other, >>>>>>> Cool URIs dont change. It's really hard to estimate the cost, and >>>>>>> unintended consequences of changing URIs. But my feeling is that we >>>>>>> systematically underestimate it. >>>>>>> >>>>>>> IMHO, It's kind of a shame that http wasnt made secure, and that a >>>>>>> new scheme https was invented. >>>>>>> >>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> Comments welcome. >>>>>>>> >>>>>>>> Thanks >>>>>>>> >>>>>>>> -- >>>>>>>> >>>>>>>> >>>>>>>> Phil Archer >>>>>>>> W3C Data Activity Lead >>>>>>>> http://www.w3.org/2013/data/ >>>>>>>> >>>>>>>> http://philarcher.org >>>>>>>> +44 (0)7887 767755 >>>>>>>> @philarcher1 >>>>>>>> >>>>>>>> >>>>>>> >>>>>> >>>>>> ------------------------------------------------------------ >>>>>> IHMC (850)434 8903 home >>>>>> 40 South Alcaniz St. (850)202 4416 office >>>>>> Pensacola (850)202 4440 fax >>>>>> FL 32502 (850)291 0667 mobile >>>>>> (preferred) >>>>>> phayes@ihmc.us http://www.ihmc.us/users/phayes >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>> >
Received on Saturday, 21 May 2016 16:52:40 UTC