Minutes: XDI TC Telecon Thursday 1-2:30PM PT 2010-10-14

[Drummond Reed <drummond.reed@xdi.org>]

Following are the minutes of the unofficial telecon of the XDI TC at:

Date:  Thursday, 14 October 2010 USA
Time:  1:00PM - 2:30PM Pacific Time (21:00-22:30 UTC)

ATTENDING

Bill Barnhill 
Giovanni Bartolomeo
Markus Sabadello
Michael Schwartz 
Drummond Reed
Joseph Boyle

REGRETS

Joe Johnston

THE GOTOMEETING FOR TODAY IS:
     https://www2.gotomeeting.com/join/969244355

THE IDEARPAD LINK FOR TODAY IS:
      http://xdi.idearpad.org/10

Please try to preface each of your comments with your name so the transcription into the minutes is easier.


1) UPDATED METAGRAPH SYMBOL PAGE

We went over an update to the wiki page we discussed last week (since renamed as follows):

    http://wiki.oasis-open.org/xdi/MetagraphSymbols

Bill: So what about (+x)(+y) as opposed to +x(+y)?

Drummond: (+x)(+y) identifies the context of +y in the context of the context of +x while +x(+y) identifies the context of +y in the context of +x.

So elsewhere in the table ((+x)) is labelled as the context of the context of +x. So shouldn't "the context of +y in the context of the context of +x " then be translated as ((+x))(+y) instead of (+x)(+y)?

Drummond: No, because subsegment order also expresses context. For example, +x+y identifies +y in the context of +x.

Bill: Ok, so I'm still unclear on the semantic difference between +x(+y) and (+x)(+y).  Can you describe offline if you'd like so as to not rathole..I'm particularly interested in how you'd differentiate these two XRIs using the Set membership POV.

Drummond: I can't answer from the set membership POV yet (I need to understand that POV better - I'm very interested in it), but we can draw the graphs for each of these and that should help make it clear. What I am happiest about is the clear translation of XRI cross-reference syntax to graph notation and vice versa. It makes possible sophisticated expressions (such as =a/+believes/(=z/+knows/(=b/+loves/=c)) while still having completely unambiguous machine-understandable graphs 

See also the attached PNG file with graphics, drawn by Mike on the GoToMeeting screen during the call, that illustrated how cross-references are graphed with these semantics.


2) LINK CONTRACT EXAMPLE PAGE

Drummond showed an example of the simplified link contract  format that is possible due to the improved semantics of the metagraph  symbols. There was not time to go over it in depth, but we will do that next week if there is time. See the action item list below.


3) ACTION ITEMS

* Giovanni will post an email about his concerns about current patterns for expressing subjects, predicates, objects and contexts in the XDI global graph

* Giovanni will post a wiki page with his proposed set of constructs/operators for XDI 

* Drummond will coordinate assembly of a wiki page documenting the proposed link contract structure and all processing steps involved with Alice/Bob scenario.


4) NEXT CALL

The next call is next week at the regular time. The agenda will be the action items listed above in the order they are listed.

------------
ONGOING ISSUES LIST

Each of these is a candidate for the agenda for future calls.

*  Equivalence semantics: close on whether we need an additional $ word  that is the equivalent of Higgins Personal Data Model (PDM)  semantics  of h:correlation, which is not as strong as $is.

      http://lists.oasis-open.org/archives/xdi/201006/msg00036.html

* Cool URIs: continue previous discussion about the use of standard RDF URIs in XDI:

  http://lists.oasis-open.org/archives/xdi/201006/msg00023.html

graph-diagrams-2010-10-14.png