Not Ready for Primetime

I think I really scrooched the pooch on that one.

Converting this blog to .xml with MathML extensions proved even worse for accessibility than I imagined. Of course it rendered beautifully in Mozilla. But Internet Explorer refused to render the page at all, and OmniWeb decided to download the source, rather than attempting to render it in the browser.

I guess we're not there yet, in terms of MathML. (Heck, maybe we're not there yet in terms of XHTML.) I don't know what that means for the future of using weblogs to comment on the archives. In the short term, it seems more than a little inadequate.

Anyway, I will leave a copy of the current index in MathML-enabled format, so that the brave among you can see whether your browser is manly enough to render it.

Monkey See, Monkey Do

In my previous entry, I gave an example of MathML in action. Unfortunately, Mozilla doesn't recognize that a file contains MathML unless it ends in .xml. A .html file just won't cut it. It took me a looong time to figure out why I couldn't see the syntactically-correct MathML rendered in my browser.

Eventually, I just changed all my templates to spit out filenames with extensions .xml, and all was good. But then I had to fool web surfers into downloading files with .xml extensions when they had gotten used to the .html counterparts.

Mod_rewrite to the rescue! I created the following .htaccess file for my blog directory,

# based on example in
# http://httpd.apache.org/docs-2.0/misc/rewriteguide.html
RewriteEngine on
RewriteBase /~distler/blog/
# parse out basename, but remember the fact
RewriteRule ^(.*)\.html$ $1 [C,E=WasHTML:yes]
# rewrite to document.xml if exists
RewriteCond %{REQUEST_FILENAME}.xml -f
RewriteRule ^(.*)$ $1.xml [S=1]
# else reverse the previous basename cutout
RewriteCond %{ENV:WasHTML} ^yes$
RewriteRule ^(.*)$ $1.html

deleted all the vestigial .html files, and I was good-to-go.

With Enough Eyeballs: A Manifesto

"With enough eyeballs, all bugs are shallow."
-- Linus Torvalds

In my previous comments about the Bogdanov hoax, I alluded to this oft-quoted maxim from the world of open-source software, implying that analogous benefits flowed from the use of the eprint archives to disseminate research results in physics.

But is the analogy really correct? What if there really weren't a mechanism for the thousands of readers of the source code to report back on the bugs that they have found (or to suggest improvements), except perhaps by releasing software packages of their own? Would "Torvald's Law", as it is sometimes known, still hold? Would we really still receive full benefit of those thousands of eyeballs?

Or, to put it differently, does hep-th need the analogue of Bugzilla?

Well, Bugzilla is probably not quite the right model, but I do hope that perhaps the weblog might provide such a model. While this idea has occurred to others before, three developments make me sanguine that perhaps now might be the time for it to take off:

1. The development of quality weblogging software like Movable Type eases the burden by automating most of the content-management.
2. The Trackback feature of Movable Type provides an automated way to link back to another site which references a given article. Without this feature, it would be hard to discover what others might have said by way of followup on a given topic. Since there is an Open Specification for Trackback, it can be incorporated into other software, perhaps someday including the archives themselves ("Click here to see commentaries on this paper.").
3. MathML 2.0. As you can see from previous posts to this weblog, math support in HTML is crude, at best. But MathML is now standardized, and at least one browser (Mozilla) is sufficiently compliant with all the latest standards to implement it.

This last point is, I think, the diciest. If we wish to use this venue for discussing physics, we need a nice way to do math. There are automatic converters, say, from LaTeX to MathML. The difficulty is on the browser end. If we start including snippets like

${\displaystyle \coprod _{i=0}^{\infty }{x}_i}$

in our posts, they will be inaccessible to those with "lesser" browsers like Internet Explorer. This is not a matter of using "proprietary" features of some particular browser. I validate all these pages to ensure that they are perfectly conformant with the published XHTML standards. Its just that not everyone has (yet) implemented those standards.

Or maybe a little elitism is just what we need anyway. What do y'all think?

Revenge of the French Intellectuals

Stung by the Sokal Hoax, two French brothers, Igor and Grichka Bogdanov, have made a stab at righting the scales. They managed to obtain PhDs from the Université de Bourgogne in Dijon and publish 4 papers filled with nonsense:

KMS Space-Time at the Planck Scale, G. Bogdanov, I. Bogdanov , Nuovo Cim. 117B (2002) 417-424.
The KMS State of Space-Time at the Planck Scale, I. Bogdanov , Chin.J.Phys. 40 (2002) 149-158.
Space-Time Metric and the KMS Condition at the Planck Scale, G. Bogdanov, I. Bogdanov, Annals Phys.296 (2002) 90-97.
Topological Field Theory of the Initial Singularity of Space-Time, G. Bogdanov, I. Bogdanov, Class.Quant.Grav. 18 (2001) 4341-4372.

What this says about the French PhD system or refereeing in the journals (and some journals they chose! Nuovo Cimento? The Chinese Journal of Physics? Gimme a break!) is anyone's guess. But the most curious aspect of the affair was that they never even bothered to submit their masterpieces to the eprint archives. Which is to say that no one (and I do mean not a single person) actually read this stuff before the story broke...

For those unfamiliar with the field, let me explain what that means. The abstracts of new papers submitted to hep-th are read daily by thousands of physicists. If the abstract sounds interesting, hundreds will download and read it. Feedback (positive or negative) comes swiftly and copiously. If (like 99.9% of all scientists), you want to get your work noticed and read, you send it to the archives.

If, on the other hand, you want your work to "fly under the radar" and make it into a journal, having been read only by one other person (the overworked referee, and, in this case, perhaps not even by him), then you studiously avoid sending your work to the archives. Since no one in our field reads the journals anymore (why bother, when the archives are so much more convenient?), no one will be the wiser.

For more discussion of the unfolding "scandal", see this Usenet thread.

The plot thickens: The Bogdanov brothers are not listed among the current or recent PhD students of the Lab. Have their names been pulled from the website, or is this all a put-up job?

Apparently, the Bogdanov brothers have been at this game for a while.
I've been pulling up reviews on the web of their 1991 book, "Dieu et la Science" (God and Science), written with Jean Guitton of the Académie Française. From the excerpts, it appears to be written as an extended "interview", with Guitton as the interviewer, and the Bogdanov brothers responding (with what sounds to me to be mostly bullshit). But . . . and here's the interesting bit . . . all the reviews I pulled up from Google credit the Bogdanov brothers as having PhDs in theoretical physics and astrophysics (when they wrote the book, in 1991!).

Blogger.com Hacked

I suppose it should come as no surprise that blogger.com was hacked today.

Most interesting, I thought, was the relatively warm praise this piece had for the security of Movable Type compared to blogger.com. Those of you who have been reading these pages know about my grumblings about the security of MT. I can only imagine what that means about blogger.com.

Overall, I think it's a good thing that a greater focus on security come to this genre of software. Pity if it comes at the expense of all those blogger.com users.

Blogging from the Road

I'm in Cambridge, MA, but I thought I'd mention a couple of papers of recent interest.

David Berenstein had a nice paper today in which he investigates a couple of gauge theories with quantum-deformed moduli spaces from the matrix-model approach of Dijkgraaf-Vafa. Probably the most interesting example is an SU(2) gauge theory with three adjoint chiral multiplets with superpotential

W = g ( Tr( XYZ+ZYX)-2Tr(X+Y+Z) )

This is the worldvolume gauge theory on a bulk probe brane near the C³/Z₂ ×Z₂ orbifold with discrete torsion.

Another intriguing ("intriguing" is all I'm about to commit to right now) paper appeared yesterday by Yonatan Zunger.

In the context of matrix theory, one can reproduce various D-brane configurations by letting the X's of the matrix theory (at finite N, they are NxN matrices) in the infinite N limit turn into operators which act as derivations on some algebra, A.

Actually, even in empty flat space , we can consider X⁰ = d/dt + A₀ as a tenth "X", which acts as a derivation on the algebra A= C(R)×M_N. In flat space, the rest of the X's (acting by commutator, [X,.]) are "inner" derivations of this algebra. In matrix string theory, two derivations are "outer", and eight are "inner".

His general proposal is to consider an arbitrary algebra, A, with some number of inner and some number of outer derivations. This he proposes as a generalized D-brane configuration in the matrix realization. It is characterized by k (k >2) classes in the Hochschild Cohomology H¹(A) (essentially, the number of X's which are outer derivations), and a class in the algebraic K-theory K₀(A), which gives the "charge" of the D-brane configuration.

Anyway, time to get myself some dinner. More later . . .