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Subject: RE: [xri] polyarchical -vs- hierarchal
Les (and Wil, since this also addresses
your question): First, per the message I just sent, IMHO no
normalization rule between @ootao+west and @ootao*(+west) can satisfy the human-usability
requirement. Second, I’ll try to be precise about
the context differences. Each of the six context symbols defines a context as
follows: LOCAL CONTEXT SYMBOLS (LCS) * à reassignable identifier assigned in a local context, i.e., can
only be interpreted as identifying a resource in the context of the authority
assigning the identifier. ! à persistent identifier assigned in a local context, i.e., can only
be interpreted as identifying a resource in the context of the authority
assigning the identifier. GLOBAL CONTEXT SYMBOLS (GCS) = à identifies the global context of identifiers assigned by
individuals @ à identifies the global context of identifiers assigned by organizations = à identifies the global context of generic identifiers (tags) assigned
by general community consensus $ à identifies the global context of identifiers assigned by standards
bodies in specifications for the specific purpose of interoperable
identification of resources. Having defined these, here’s what I
meant by contrasting hierarchical and polyarchical usage: 1) The two LCS characters are similar to
dots in DNS syntax or the slashes in URI syntax – they provide for hierarchical
delegation between identifiers whose context is always local, i.e., their
parent. Thus they have no polyarchical usage. 2) The four GCS characters have no precedent
in DNS or URI syntax. They too allow for hierarchical delegation, but they
allow the use of identifiers that *have their
own independent global context*, i.e., are absolute identifiers in
their own right. That’s the polyarchical usage – the ability to
take an identifier rooted in one context and reuse (cross-reference) it inside
another context. In XRI 2.0, there was only one way to take
an XRI that exists in one global context – such as +west – and put
it in another context, and that was using parenthetical cross-reference syntax
that forced it to also be put into a local * or ! context, i.e., *(+west) or !(=west).
However with direct concatenation, this
forcing is no longer necessary. You can now put one global XRI directly in the
context of another global XRI -- @ootao+west, @cordance+west – without being
forced to say that its interpretation is limited to a local context. Essentially, that’s what normalizing
+west into *(+west) or !(+west) is doing: taking an identifier whose purpose is
to be interpreted in a global context and saying “the following
identifier SHOULD NOT be interpreted outside the local context”. By contrast, allowing direct concatenation
of @ootao and +west into @ootao+west finally enables us to clearly express the intended
usage of the vast majority of cross-references: “the following identifier
(+west) SHOULD be interpreted outside of the local context”. Hope this helps, =Drummond (now going to bed ;-) From: Chasen, Les
[mailto:les.chasen@neustar.biz] You are still not distinguishing very well
the difference between local and global subsegments. The descriptions you
are providing in both cases are local delegations in the context of a
parent. So as Steve keeps asking why doesn’t @ootao*(+west) satisfy
the requirement? If the meaning is different it is unclear how so?
I thought today you were saying that @ootao+west is not a hierarchy but a
polyarchy. From: Drummond Reed
[mailto:drummond.reed@cordance.net] Les, Actually, in XDI (both the ATI and RDF
models), all link relationships are represented as delegations (either *!
delegation, or =@+$ delegation) inside a single XRI segment. All hierarchical
parent/child relationships are represented as forward-slashes (different
segments). When you create a link between two
resources, you are naming the arc that connects the two nodes. So for @ootao,
you first need a starting node, which is @ (the “arc from
nowhere”), and then “ootao” is the link to the next node. The
same goes for +west -- + is the starting node, and “west” is the
link (arc) to the next node. In @ootao+west, @ is the starting node,
“ootao” is the link/arc to the second node, and “+west”
is the link/arc to the third node. It is true that + may point
“west” to a different node (and different XRD) that @ootao points
“+west”. That’s the difference between their contexts.
However the purpose of the + namespace is to provide common context (generic
identifiers), so the idea is that both +west and @ootao+west point to resources
that serve as THEIR representations of the generic subject “west”.
In the + dictionary space, this representation should be a definition. In the
@ootao space, it could be any resource that @ootao identifies (and wishes
others to be able to generically identify) as “west”. Note that if
using “+west” all by itself might be ambiguous, @ootao can do the
same thing Wikipedia does and add more context (Wikipedia refers to this as
“disambiguation” – see http://en.wikipedia.org/wiki/Wikipedia:Disambiguation
for a great summary of this.) To do this, @ootao could create XRIs such as:
@ootao+office+west
@ootao+division+west Hope this helps, =Drummond From: Chasen, Les
[mailto: Drummond – In a conversation today, you stated, I think, that we need
global subsegments so that we can move from simply a hierarchical relationship
to a polyarchical one. I think this means that with the advent of global
subsegs we now can move from one hierarchy to another one. I think
in XDI you call these things links. I thought we support this today
through the use of REFs in the XRDS. Now, I suppose, that you are
proposing that we move this notion into the syntax layer. These examples of hierarchical XRIs truly show local
delegations. @ootao*west @ootao*(+west) These examples of polyarchical XRIs demonstrate a global
relationship (link) @ootao+west @ootao+west*steve Is this accurate? If so, my main heartburn is that
since +west in @ootao+west as currently proposed is in the context of
@ootao. This means it could be completely different then the view from
+. If we are really linking to another namespace, +west, we should get
+’s view of west not @ootao. Thoughts? contact: =les chat: =les/skype/chat |
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