Holographic XML

["Costello, Roger L." <costello@mitre.org>]

Hi Folks,

Just brainstorming ...

Consider:
 
1. Holography is where the information about the 3 dimensions is stored in 2 dimensional space.

2. I've been told by industry experts that if you're not in the 3-D memory business in four years, you're not going to be in the memory business.

http://www.eurekalert.org/pub_releases/2010-08/ru-soc083110.php 

Operating in 3 dimensions seems to be something that will be increasingly important.

XML is kind of a 2 dimensional representation of data. How can XML expand to 3 dimensions?

...

Here are two responses from colleagues:

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3-D storage is really only about increasing the size of an array.  There's no additional complexity, only increased space organized differently.

byte [1024][1024] twoD;
byte [1024][1024][1024] threeD;

Notice that the addressing and storage method are basically the same, but "threeD" is undeniably way bigger.

This analogy doesn't really carry over to XML.  You can't "increase the space" or density of an XML document, because it's already arbitrary according to the user's whim.  The only way I can possibly think to carry over the analogy to XML is to increase the "degrees of freedom" in an XML document by abandoning the hierarchy/rooted-tree constraint, and making it possible to represent arbitrary graphs.  (After all, trees are only a special case of graphs)  We can already do this today with RDF and other XML-serialized graph representations.  Notice that unlike 3-D storage, this introduces different semantics, not just another array dimension.  Good for some things, not for others.

David

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I agree with David.  Along the notion of additional "degrees of freedom," check out "Colorful XML: One Hierarchy Isn't Enough" by Jagadish et al.:

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.70.9790&rep=rep1&type=pdf 

Peter

...

Ideas?

/Roger