From time to time you may see here a message that NeverEndingBooks ends on Bloomsday (June 16th). Soon after, I hope to restart with another blog at the same URL. For starters, Neverendingbooks refers to my never-ending bookproject on noncommutative geometry started in 1999, a millenium ago… Today I\’m correcting the proofs and have even seen the cover-design of the book, supposed to be published in the fall. So, it should be really EndingBook(s), finally. From time to time it is good to start afresh. The next project is still pretty vague to me but it will be a lot more focussed and center around topics like Moonshine, the Monster, the Mathieu groups, Modular forms and group etc. Suggestions for a blogtitle are welcome (M-theory is already taken…). Besides there are technical problems with the machine running the blog, a new one is expected around June 16th. As I will not be able to clone between the two (one PPC, the new one Intel) I decided to start again from scratch. Anyway, Ive made a database-dump of NeverEndingBooks and will make it available to anyone interested in reading old posts (even the ones with a private-status). Finally, there are other reasons, better kept private. Give me a couple of weeks to resurface. For now, all the best.

It has been a difficult design decision, but I‚Äôm going to replace the LaTeXRender Wordpress Plugin for mathML as the default TeX-interface for NeverEndingBooks. I will keep LaTeXRender on standby as I may have to use exotic packages or commands that iTeX does not deliver, but for most math-related posts, MathML will do the job nicely (as the n-category cafe shows every day (or even more often)). Not that I stopped being a dilettante but I’m going to do most of my writings (including blog-posts) using Scrivener (more on this another time) and Scrivener supports MultiMarkdown and allows exporting to LaTeX and XHTML (using MathML).

I could never have pulled this off in such a short time without Jacques Distler more or less on constant stand-by (thanks Jacques!). Looking at the times his emails were send I have no idea in which time zone he lives (let alone sleeps…). So, here a walk-through the changes :

As I’m on WP 2.0.5 I’ll start with Frederick’ post. He tells me I have to install first the itex2MML binary as explained by Jacques but I find that there is more recent material and therefore download the most recent imath2MML-package and follow the readme. There is a Mac OSX binary but it’s not clear for what processor (PPC/Intel/Binary) but a quick mail to Jacques learns me that it’s PPC which is fine by me but on the spot he puts a universal binary online, so whatever your Mac is you can just download the binary, copy it to /usr/local/bin and make sure its chmodded 755.

Back to Frederick’s post, download and install the plugin itexToMML.php in the usual way (fortunately I spot just in time that I have to change one line saying where my itex2MML binary is (in Frederick’s file it is NOT the default location)). You can verify whether the plugin and itex2MML do what they are supposed to do by typing a LaTeX-command in a post and save it. The output will not produce the desired formula but have a look at the source file and see whether there is some mathML code in it. If so, fine! If not, go back and check everything.

If this works, it is “merely” a problem of getting your mathML served. Frederick suggests to unpack wordpress_mathML.zip in the wp-includes directory (but you better make sure you have made a copy of the original class.php and functions-formatting.php files. In the end I decided against this approach (that is, to replace only the functions-formatting.php but NOT the class.php file). If you have two or more themes you want to maintain, it is probably better to change the headers (because this is what we have to do to get mathML served) only in those themes which are XML-sound. In my case, the Command Line Interface theme most certainly is NOT!!!).

Go to your theme-files and look for the header.php (or similar) file and replace the default header by the code in the addendum to this post within php-tags. If you can go to your blog-page then you are in good shape and things should work well (apart possibly from layout considerations, see below). Of course, in my case i was greeted by ” XML “yellow screen of death” (as Jacques calls it) and I was convinced I did something wrong, so I tried out several useless things for a couple of hours before it dawned on me that the reason might just be that my blog-files were not valid XHTML (and the new headers are very demanding on serving only well-form XHTML). I had to modify all changes I made to sidebars etc. as well as rewrite parts of my first posts (I used to take a rather liberal view on writing blog-posts, writing a mixture between Markdown and improvised HTML and in the process was very lax about closing IMG-tags and the likes). But after some time and numerous corrections to the files I got the main-page up and running (and even had the mathML served as a readable formula) apart from the fact that I barely recognized my own site.

I printed out source files of the page with and without changed headers and couldn’t find a difference. So, it had to do with the CSS-style files, but why on earth would the new headers be picky about CSS? But as a last resort, after narrowing the search down to one CSS-line, I asked Jacques whether he had an idea what went on. His reply will be remembered for quite some time :

A fascinating question. The answer is that it is following the CSS directive, but in XHTML, ‘body’ is not what you think it is. ‘body’ is just big enough to contain its content. It does not fill the viewport. ‘html’ fills the viewport. The solution (a solution) is described in
http://golem.ph.utexas.edu/~distler/blog/archives/000203.html

Many hours later, I still haven’t got a clue what this is all about, but I blindly followed the hint and surely all problems vanished. In short, another day wasted in front of a computer-screen.

At the moment I’m back to old headers and will not be writing mathML for some time as I have the vast job ahead to validate all my previous posts to XHTML-standards (if not you would see more yellows screens of death than anything else. So, here‚Äôs the strategy I’ll be taking in the weeks ahead (I’ll sleep on it tonight so if any of you think there is a better way, reply quickly)

• rewrite each and every post in proper MultiMarkdown using iTeX for the most common math and only resorting to LaTeXRender for exotic things (such as Sudoku, Chess, Dvonn) and run these posts through Markdown (to get basic HTML and all links in place).
• download these files to the WP-database (so that in the CLI-interface you will be able to follow all links, but will read all iTeX as TeX-commands (as the command line intended after all).
• in the process change all broken links to the default permalink-structure (with index.php?p=231 or so).

Clearly, this is a work that will take a couple of weeks but it may be fun to reread these old posts and possibly add new information about the subjects. When I’m making these changes, I’ll use the new headers so if you are using a smart browser look out for the yellow screens. When they happen, either use a dumb browser (such as Safari) or go into CLI-interface mode where everything should still work. I plan to start with the oldest posts as this seems more fun to me.

Way back in 1999 I read Neal Stephenson’s pamphlet In the Beginning ! Was the Command Line and decided I should and would have Linux running on my clamshell iBook. Needless to say this was (a) a foolish idea and (b) not entirely trivial in those dark OS 9-days. Still, I somehow managed with the help op PPC Linux and was proudly wearing their T-shirt (at least for a couple of weeks in early 2000). Fortunately, as a brief OS X history recalls, OS X was released March 24, 2001 and put an end to my Linux-folly and I’m pretty certain even Neal Stephenson is on Mac OSX these days.

Needless to say I couldn’t resist installing the Wordpress CLI-theme the moment I spotted it! A command line interface to your blog! awesome! If you want to have a go at the original version, take a look at Rod McFarland’s blog. Just type ‘ls’ to the prompt and you’ll be hooked. Or you can have a look at the command line interface of NeverEndingBooks by going to the left sidebar and clicking CLI under the ‘Command Line Version’ header (don’t be afraid you can always come back by clicking on the GUI-interface over there). My design is black on a light-gray background and is no where near as cool as the original theme but it was the only quick way around some limitations of the CLI-theme.

The CLI-theme operates as a front-end via a small interpreter which draws the information directly from the WordPress-database. As a result you loose the effect of all post-processing by plugins such as Markdown and LatexRender two of the plugins I use most! I could still live with the idea that pure LaTeX was served to a CLI-environment between tex-tags, but surely I didn’t want to loose all my links! The quick (and extremely dirty) way around it was to resubmit the relevant part of the HTML-source files of the GUI-frontend posts to the WP-database. And to serve the same LaTeX-gifs to the GUI and CLI interface I needed the backgound to be rather light gray (taking #BDBDBD gray would have been much nicer wrt. the cool rasterized grayed-images but then some of the more recent LaTeX-gifs became partially unreadable). Oh, and in the process I had to update the permalink structure, thereby wrecking allmost all internal reference-links (but I’ll sort them out soon, I promise).

So, a lot of work for a rather meagre result. What do I like about the CLI-interface (apart from old time nostalgia)? I really like the searching facility. Just type ’search yourword’ to the prompt and it will give you all posts containing that word (much quicker than in the GUI-interface) and if you remember at least one word from a post-title, feeding it to the prompt will give you the entire post (or a list of posts if the same word appears in different posts). Try out typing ‘Perelman’ to see what I mean. Besides, bots don’t seem to know what to do with the CLI-interface so for the few days I had this theme as my default theme I was alone on NeverEndingBooks mast of the time (which helped a lot having to change that many posts). So, whenever I want to have the site to myself I’ll just change the default theme from now on.

Still, I did put back the old GUI as default because the CLI-theme still has a few drawbacks. Such as, it is impossible to write a sizable comment (not that too many of you do this, but anyway) and some other quirks. Still Rod McFarland is working on a version 2 (and even set up a google-group for those who want to code along, and maybe I’ll join the effort) which promises a great improvement and I’m rather confident that by version 3.14 it will be in a state that I’ll have the CLI-interface as my default. Until then, I’ll keep up the two front-ends and allow you to toggle as you like (your browser will remember your preference).

I realize most of you are youngsters and not of my cpu2 generation so have a hard time imagining how exiting a command line prompt is. Fortunately, Neal Stephenson has made the full text of “In the beginning ! was the command line” available as a free download. Print it out and enjoy!

The Klein Four Group is an a capella group from the maths department of Northwestern. Below a link to one of their songs (grabbed from P.P. Cook’s Tangent Space ).

Finite Simple Group (of order two)

A Klein Four original by Matt Salomone

The path of love is never smooth
But mine’s continuous for you
You’re the upper bound in the chains of my heart
You’re my Axiom of Choice, you know it’s true
But lately our relation’s not so well-defined
And I just can’t function without you
I’ll prove my proposition and I’m sure you’ll find
We’re a finite simple group of order two
I’m losing my identity
I’m getting tensor every day
And without loss of generality
I will assume that you feel the same way
Since every time I see you, you just quotient out
The faithful image that I map into
But when we’re one-to-one you’ll see what I’m about
‘Cause we’re a finite simple group of order two
Our equivalence was stable,
A principal love bundle sitting deep inside
But then you drove a wedge between our two-forms
Now everything is so complexified
When we first met, we simply connected
My heart was open but too dense
Our system was already directed
To have a finite limit, in some sense

I’m living in the kernel of a rank-one map
From my domain, its image looks so blue,
‘Cause all I see are zeroes, it’s a cruel trap
But we’re a finite simple group of order two
I’m not the smoothest operator in my class,
But we’re a mirror pair, me and you,
So let’s apply forgetful functors to the past
And be a finite simple group, a finite simple group,
Let’s be a finite simple group of order two
(Oughter: “Why not three?”)
I’ve proved my proposition now, as you can see,
So let’s both be associative and free
And by corollary, this shows you and I to be
Purely inseparable. Q. E. D.

SAGE (which stands for ‘Software for Algebra and Geometry Experimentation’) includes and offers an interface to GAP, Singular, Maxima and even PARI as well as an interface to other packages such as Maple, Magma and Mathematica (see here for a full list of its features). More importantly, Sage offers a binary for both PPC and Intel-Macs! I did check this out and it runs without problems, in fact, after this initial check I installed from the sources on my MacBook Pro and after one hour of compiling I did have working (though not full) versions of GAP, Maxima and Singular. At first I was a bit worried that only small subsets of the three systems were installed, but it is quite easy to extend your Sage with additional packages. From the Unix-prompt do a sage -optional
and you will get a list of all (additional) packages you have already installed and those available for installation. SAGE is pretty well documented with tutorials and reference manual to be found here. Even if you do not want to learn (yet) the Sage-commands but just want to continue using the programs under its hood, this is pretty easy. For example, to get to Maxima, you only have to type !maxima from the sage-prompt to open up a maxima-session (and similarly for Gap and Singular).