- From: Henry Story <henry.story@bblfish.net>
- Date: Mon, 11 Nov 2013 19:45:54 +0100
- To: Steve Battle <steve.battle@sysemia.co.uk>
- Cc: Alexandre Bertails <bertails@w3.org>, Linked Data Platform WG <public-ldp-wg@w3.org>
On 11 Nov 2013, at 19:22, Henry Story <henry.story@bblfish.net> wrote: > > On 11 Nov 2013, at 18:36, Steve Battle <steve.battle@sysemia.co.uk> wrote: > >> I thought that "being an LDPR" meant "being a member of an LDPC". >> >> Questions about Barbers and people who don't shave themselves >> notwithstanding, there's at least one LDPC, and hence an LDPR by >> implication, that is not a member of a LDPC. > > This shows that the notion of an LDPR is logically prior to that > of membership, and that LDPCs are causally prior to their members . > > Anyway there are some definitions in the spec: > > [[ > Linked Data Platform Container (LDPC) > An LDPR representing a collection of membership triples which is uniquely identified by a URI that responds to client requests for creation, modification, and enumeration of its members. > > Membership triples > A set of triples in an LDPC's state that lists its members. A container's membership triples all have one of the following patterns: > membership-constant-URI membership-predicate member-URI > member-URI membership-predicate membership-constant-URI > The difference between the two is simply which position member-URI occupies, which is usually driven by the choice of membership-predicate. Most predicates have a natural forward direction inherent in their name, and existing vocabularies contain useful examples that read naturally in each direction. rdfs:member and dcterms:isPartOf are representative examples. > Each container exposes properties that allow clients to determine which pattern it uses, what the actual membership-predicate and membership-constant-URI values are, and (for containers that allow the creation of new members) what value is used for the member-URI based on the client's input to the creation process. > ]] > > The spec then tells us how to "create, modify and enumerate" members. But the spec does this by > describing actions on LDPRs using GET, POST and DELETE. GET enumerates the members, DELETE deletes > a member, POST creates one. > > What is missing in the spec is the definition of the ldp:member relation that relates the LDPC to > the LDPRs on which the above actions can be exercised to change the membership triples. We can define > it and thereby make things much clearer. Let me propose the following ldp:member definition > > ldp:member a rdf:Property; > ldp:domain ldp:Container; > ldp:range ldp:Resource; > ldp:comment """ > An ldp:member of a ldp:Container is a LDOR which is created when a POST succeeds > on it (creates via the membership triples) or which when DELETED removes the membership > triples.""" > > ldp:created refs:subPropertyOf ldp:member; > ldp:comment "relates an ldp:Container to a LDPR which is created when a POST succeeds" . > > The ldp:member relation is useful to make it clear what the LDPRs on which to act > to change the membership triples. > > If we can agree on this then we can have clearer conversations perhaps. I put up the definition, with some obvious fixes, in the wiki here: http://www.w3.org/2012/ldp/wiki/Member So that we can re-use it in later discussions. > > Henry > >> >> Steve. >> >> -----Original Message----- >> From: Alexandre Bertails [mailto:bertails@w3.org] >> Sent: 11 November 2013 16:49 >> To: Linked Data Platform WG >> Subject: What does "being a member" mean? >> >> Guys, >> >> I think we have a problem with semantics :-) >> >> Can somebody tell me what "being a member" means? >> >> I thought that "being an LDPR" meant "being a member of an LDPC". >> >> How is that different from "being managed by an LDPC"? And from >> "ldp:created"? >> >> Are the LDP interactions driven by "being a member" or by "being an >> LDPC/LDPR"? >> >> Is the notion of membership achieved through membershipXXX? If not, what's >> the name for the feature captured by the membershipXXX relations? >> >> If a POST succeed, does it mean that the new resource is created, or >> managed, or a member of the LDPC? What about a binary resource then, as >> it's currently not considered as an LDPC? >> >> Sorry if those are obvious questions, but when I hear the conversations we >> have in the meetings, it looks pretty confused :-/ >> >> Alexandre. >> > > Social Web Architect > http://bblfish.net/ Social Web Architect http://bblfish.net/
Received on Monday, 11 November 2013 18:46:31 UTC