## September 2, 2007

### Toward a Higher-Dimensional Wiki

#### Posted by John Baez

The n-Category Café has been around for just over a year now!

Congratulations! Thanks to everyone for making it a success!

Perhaps the time has come for a wiki.

I’ve been wanting to write a book on higher-dimensional algebra for many years, but I’ve been slow to get started. Why? I’ve written books. I know what it’s like. The very thought of writing another makes me feel tired, not energetic. It’s such a solitary pursuit, and the payoff comes only after so much labor. The whole idea of books is looking a bit old-fashioned. A wiki, on the other hand, is a communal enterprise. And, it’s fun from the very start!

I’m not the only one here who feels this way. Not too long ago, Urs wrote:

With all this Wiki expertise materializing here, would anyone fancy setting up an $n$-Category Wiki to accompany this blog? Where we could host copies of that material which isn’t just chat, but, you know, real content. Some place where John Baez would gradually develop the Tale of Groupoidification, for instance, keeping it from being spread over many entries and TWFs. Where we would gradually maybe work on material which we are either reviewing or – as happens from time to time – coming up with ourselves.

This suggestion (of accompanying the Café with a Wiki) is not new. Others here have expressed it already more empathetically even.

Empathetically, or emphatically? It doesn’t matter. The point is, here at the n-Category Café we’re not just committed to n-categories. We’re committed to newer, better ways of doing things — including new forms of communication.

Urs has written tons of material, but a blog is not optimal for finding all that material. A blog is great for conversations, but we also need something that’s more like an enormous collection of papers organized according to subject. For example, I’d like to put the old Tale of n-Categories and the new Tale of Groupoidification someplace where they are easier to find. Somebody has even TeXed up the former tale for me — I just need to edit it a bit more! And then there’s that book-like thing I still want to write…

The Higher-Dimensional Wiki (or whatever we call it) would definitely need to have good support for TeX. Given the difficulty so many people have with downloading the fonts needed to read the math on this blog, I think jsmath could be a good way to go. It’s open-source, and it seems to be gaining a crowd of people who write little programs to make it work better. A snowball rolling downhill, getting bigger as it rolls — that’s a good kind of technology to join. I don’t know if jsmath is right, but it’s worth checking out. Look at examples of jsmath in use, like this math textbook — or even better, Garrett Lisi’s wiki. Garrett has offered to help set up a similar wiki on my website.

Blake raises the issue of privacy versus openness:

I’m not particularly happy with MediaWiki’s math support. Scope out a few Wikipedia articles on math topics to see if you like it and how it’s done; you can also create yourself a EUREKA account and play around there.

How do you imagine this wiki will be edited? Do you want a site edited by only a few people — say, the Café hosts and a few others on an invitation-only basis — or would you prefer something more open, like EUREKA? In the former situation, we might try setting up something like Instiki, which lets you keep the wiki proper a private entity and export a static version for public consumption.

Urs favors openness. Chris Hillman favors privacy.

I favor flexibility.

I might decide I don’t want people messing with the old Tale of n-Categories… or I might decide it’s great to let people correct typos. It’s hard to tell ahead of time.

Certainly it would be great to have patches open where random people could contribute articles defining and explaining basic concepts in category theory, and n-category theory. It might be nice to start by borrowing Wikipedia articles on certain topics — I think that’s perfectly legitimate if one follows the rules. Then, when we decide to write something more advanced, we can insert links to those defined terms. Or, maybe we should just link to the Wikipedia, and take advantage of their snowball, which is rolling downhill and growing really fast.

Either way, these are some of the reasons I’m more excited about writing a wiki than a traditional book. Imagine: learning n-category theory, and being able at any moment to click on any term you don’t understand, to find more explanation. Imagine: not a static book, but an ever-growing body of information. Imagine: not something you buy from Elsevier, but something free to all.

Posted at September 2, 2007 12:38 PM UTC

TrackBack URL for this Entry:   http://golem.ph.utexas.edu/cgi-bin/MT-3.0/dxy-tb.fcgi/1416

### jsMath

jsMath is great; Dave Cervone is a genius. It’s far-and-away the best option for embedding math in “ordinary” HTML pages. But I warn you (and Dave will assent) that it can be really slow on math-heavy pages.

Posted by: Jacques Distler on September 2, 2007 5:44 PM | Permalink | PGP Sig | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Hey everyone!

Congratulations to the cafe!

I don’t know if it’s the right place for the following comment, but I can’t think of a better one.

The cafe in many ways replaced the newsgroup sci.physics.research. The newsgroup still exists, but it appears that many of its most interesting participants abandoned it. Our hosts in the cafe and many of its regulars are prominent examples.

The question I want to ask is whether the trade was lossless. While the cafe is in some ways superior to spr (for instance it is not infested by crackpots), it cannot perform all of the former’s functions. In particular, a humble guest like myself can only reply to existing entries, not create new ones. Which is only appropriate, the cafe being a group blog rather than a public forum.

Therefore, while I greatly appreciate and enjoy this wonderful blog, I also feel that the decline of sci.physics.research and the rise of the n-category cafe left an important niche empty.

I’m not sure I have a specific suggestion, but I think the issue is worth discussing. I would be glad to hear other people’s ideas on the subject.

Posted by: Squark on September 2, 2007 7:19 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

I think that Squark has hit on one of the big issues with blogs:

In particular, a humble guest like myself can only reply to existing entries, not create new ones.

This situation has its virtues and also its inevitable trade-offs. Another issue of note is that it’s difficult to do a conversation across blogs, or to pull bloggers together to work towards producing some intellectual achievement. We have “carnivals” like the CoM and Philosophia Naturalis, but those are collections of writings which have already been written, assembled after the fact. (Ditto for the “Basic Concepts in Science” series, which is basically a slowly-growing list of hyperlinks.)

Cosmic Variance recently had an open thread for cosmology questions, and Aaron Bergman did a similar thing for string theory. I wonder if this could be made into a regular affair, sort of an “Ask Professor Science!” tradition in which each month (or every N days, whatever) a different scientist-blogger hosts an open thread. If the event were well-advertised, each occasion could easily attract informed responses from many scientists other than the host, too.

Posted by: Blake Stacey on September 2, 2007 9:14 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Squark wrote:

The cafe in many ways replaced the newsgroup sci.physics.research. The newsgroup still exists, but it appears that many of its most interesting participants abandoned it.

It was certainly never our hope to ‘replace’ sci.physics.research. A blog about math, philosophy and physics focused on n-categories is really no replacement for a newsgroup about physics. Even a bunch of different blogs, run by different people, is very different from a newsgroup.

In many ways the situation is much better — especially for people who used to moderate sci.physics.research, like me. I don’t need to spend several hours a day posting articles and sending a reply to each crackpot and/or flamer whose article I decided to reject. Only a few comments here need to be deleted, and the discussion is usually more serious and focused, so flame wars rarely break out.

On the other hand:

In particular, a humble guest like myself can only reply to existing entries, not create new ones. Which is only appropriate, the cafe being a group blog rather than a public forum.

I don’t know about ‘humble’ guests — but when it comes to esteemed guests such as yourself, with a proven track record of having interesting ideas, we’re open to ‘guest posts’. Todd Trimble and Bruce Bartlett have done guest posts, and we’re always hoping for more from these guys. Would you like to try one too?

Posted by: John Baez on September 3, 2007 11:04 AM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Todd Trimble and Bruce Bartlett have done guest posts

Tom Leinster too. And perhaps there were others.

Posted by: Todd Trimble on September 3, 2007 2:39 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

And perhaps there were others.

Yes, David Roberts and Alejandro Rivero, too.

Posted by: Urs Schreiber on September 3, 2007 4:16 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Imagine: learning n-category theory, and being able at any moment to click on any term you don’t understand, to find more explanation.

One problem I’ve often found on wikipedia is when reading an article on a technical subject that I don’t already know pretty decently (like the one on the Boltzmann distribution, recently), the article is written as though being able to click on a link to any other term means that you don’t have to explain things. The result is very dense, and often reminiscent of Lang’s Algebra. It’s a great reference if you already know the stuff, and theoretically you could learn from it, but the background material is linked in a non-well-founded way, and ends up making you read far more other background material than is actually necessary for understanding the stuff.

Would it make sense to have a section of this wiki devoted to making something more like a wiki textbook than a wiki reference book? That would avoid the issue I often see on wikipedia where people feel that it’s more important to have a definitive statement of what’s going on than to have something that can tell someone who doesn’t already have a good idea what’s going on.

Posted by: Kenny Easwaran on September 2, 2007 10:52 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Yes, many things are underdeveloped on wikipedia, and having a correct definition is a decent default starting point. I have tried to add examples and motivations to various articles from time to time, and they’re either kept or expanded on. So when you figure something out, do the rest of the world a favor and explain it so we can understand it.

Posted by: Mike Stay on September 3, 2007 3:41 AM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Kenny wrote:

One problem I’ve often found on wikipedia is when reading an article on a technical subject that I don’t already know pretty decently (like the one on the Boltzmann distribution, recently), the article is written as though being able to click on a link to any other term means that you don’t have to explain things.

You’re right: links to definitions are no substitute for clear explanations. My personal dream for a book on $n$-categories would not be a linked collection of definitions, or even encyclopedia articles: it would be a real book, with real explanations. Having links to definitions would just be icing on the cake. Ideally there would be links to quick precise ‘reminder’ definitions, which would then have further links to actual explanations.

But, I’d like to see this book evolve in an ecosystem where other people were writing other things, including those definitions and explanations, but also their own papers and books…

Urs, for example, seems to be building a grand edifice involving higher gauge theory, the quantization of particles, strings and branes, and so on. Other people in $n$-category theory are building their own grand edifices. It would be nice if these could all be linked and available in one ‘place’.

Posted by: John Baez on September 3, 2007 4:49 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Just some thoughts.

When I was a kid, I tried to learn stuff from encyclopaedias (print encyclopaedias in those dim and distant days of yore), and this gave me a very clear and visceral understanding of just how very bad encyclopaedias are for learning a subject from scratch, compared to, e.g., textbooks. They’re great for either casual browsing or for looking things up (depending on the technical level) but the format inherently has the problems that Kenny described. It’s not that Wikipedia is done badly; the problem is that the strengths of the format (very easy to look things up if you already know something about them; very easy to pick up entertaining little random snippets of information) are also its weaknesses (information is fragmented, there’s no coherent progression through the material, vital background is missing).

Something intermediate between a wiki/encyclopaedia and a textbook might be a series of long, expository essays on various subjects, giving broad-picture overviews. TWF is of course the shining example of this sort of thing, but it would be interesting to get different takes on some of this material by different people.

This would hopefully be intermediate in exhaustingness between wiki articles and an actual book.

Posted by: Tim Silverman on September 3, 2007 8:55 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

TWF is of course the shining example of this sort of thing

This highlights something to bear in mind. There’s nobody quite like John. Exposition isn’t easy. I can’t imagine I’d have learned a quarter of what I know about n-categories without him.

But who knows? Perhaps other expositors work for other people. In any case, perhaps people contributing exposition to the wiki should expect substantial alterations of style and content to be the norm.

Posted by: David Corfield on September 4, 2007 9:26 AM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

David wrote some embarrassingly fulsome praise, and then:

… perhaps people contributing exposition to the wiki should expect substantial alterations of style and content to be the norm.

In the Wikipedia and other wikis using MediaWiki, there’s a little warning that goes:

If you don’t want your writing to be edited mercilessly and redistributed at will, then don’t submit it here.

But, I don’t think a format that merely mimics the Wikipedia is optimal for what we’re dreaming of here!

There should be room for encyclopedia-like entries that lots of people can rewrite. Even if these just contained bare definitions, that’d still be very handy.

But, there should be room for various people to include expository texts of their own, not editable by others. If I polish up the Tale of $n$-Categories or the Tale of Groupoidification and port them to this wiki, I don’t want other people messing with them!

But, I certainly do want a place where people can report typos, math mistakes and other problems. I’d also like ‘chat rooms’ for different texts, where people can ask questions about them — and answer them! I don’t see any big technical obstacle to this sort of thing.

The whole question of “who gets to contribute to what” is a substantial can of worms, deftly opened by Chris Hillman. I think flexibility should be the watchword. Ideally, different sets of people would be allowed to contribute to different ‘zones’ of the wiki, with a lot of freedom to set up new zones, regulated however by a benevolent oligarchy that includes — surprise! — Urs, you and I.

Posted by: John Baez on September 4, 2007 10:36 AM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

benevolent oligarchy…

Perhaps we should also try out the other three types of unjust state of The Republic: timocracy, democracy, and tyranny.

…that includes – surprise! – Urs, you and I.

Just so long as we can correct each other’s grammar.

Posted by: David Corfield on September 4, 2007 11:34 AM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Sounds very good!

It seems there is only one question left open:

How much do we need to pay Blake Stacey to set it up? :-)

Seriously, instead of talking about it, I would love to start using it.

Posted by: Urs Schreiber on September 3, 2007 4:48 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Urs wrote:

Seriously, instead of talking about it, I would love to start using it.

I don’t want to rush it, for various reasons:

1. I want to wait until Blake and others have uploaded the basic journal information to EUREKA, after which I’ll conduct a massive advertising campaign on behalf of that Wiki. There’s a limit to how many wikis we can set up per week!

2. I want to wait until I get back to UCR on September 17th, since I’m hoping to base the n-Category Wiki there.

3. Certain technical decisions should be made correctly from the start, since different formats have very different abilities to display mathematical text and (even harder) diagrams.

For EUREKA, the basic MediaWiki format used by Wikipedia seems to be fine. But I’m not sure this format is good for articles including lots of math. The math on Wikipedia looks pretty ugly, and I’d hate to get stuck with that. Surely we can do better, no? Maybe we’d prefer something like Garrett Lisi’s wiki — though as Jacques points out, the jsmath takes a while to display.
Posted by: John Baez on September 4, 2007 9:44 AM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

I want to wait until I get back to UCR on September 17th, since I’m hoping to base the $n$-Category Wiki there.

I see. What I was worried about was that we might be sitting here happily exchanging our wishlists for what the perfect Wiki for us would look like, with nobody taking the initiative and realizing anything. But I am glad to hear that you are planning to take care of it.

(I wish I could contribute more myself in setting this up.)

until I get back to UCR on September 17th

By the way, I’ll be travelling from Sept 18 to Sept 29 (first Yale, then Split), then from Oct 1 on I will probably be busy for a couple of days with helping Danny check in to Hamburg.

Posted by: Urs Schreiber on September 4, 2007 11:20 AM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

As far as the format is concerned, PlanetMath seems to be pretty good at displaying mathematics. Does anyone know how they do it?

Posted by: Robin on September 4, 2007 11:51 AM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

According to this About page, their math rendering is done by a combination of LaTeX, LaTeX2HTML, netpbm for image manipulation and gs-aladdin for working with Ghostscript. Their website is driven by Noösphere.

Posted by: Blake Stacey on September 4, 2007 6:27 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

But I’m not sure this format is good for articles including lots of math. The math on Wikipedia looks pretty ugly, and I’d hate to get stuck with that. Surely we can do better, no? Maybe we’d prefer something like Garrett Lisi’s wiki — though as Jacques points out, the jsmath takes a while to display.

I sent this as part of a private email to John and Chris. But it seems appropriate to post part of it here:

As to content, it seems to me that there are a number of competing agendas

1. a forum for expository writing, either in the form of short articles, or as a longer “book-replacement.”
2. a more organized place to refine some research ideas (e.g., Urs’s current obsession with tangent categories), which would be better than a sequence of blog posts.
3. a place where Cafe participants (like “squark”) would have greater lattitude to post things more substantial than comments on existing blog posts.

At least on point 4, Forum Software would work better than Wiki Software. But, taken together, these various goals are not necessarily reconcilable. Nor are they necessarily compatible with the strictures Chris would place on who can edit the proposed Wiki.

Personally, I would suggest that, before you set something up, you need to decide on the goals. And then choose the technology most appropriate to achieving those goals.

Posted by: Jacques Distler on September 4, 2007 3:14 PM | Permalink | PGP Sig | Reply to this

### Re: Toward a Higher-Dimensional Wiki

I agree with Jacques: we need to know a bit about what this $n$-Wiki is supposed to do before we set it up.

Since Urs is the most eager to have this $n$-Wiki, and likely to generate most of the ‘content’, he should say what he wants most:

1. a forum for expository writing, either in the form of short articles, or as a longer “book-replacement.”
2. a more organized place to refine some research ideas (e.g., Urs’s current obsession with tangent categories), which would be better than a sequence of blog posts.
3. a place where Cafe participants (like Squark) would have greater latitude to post things more substantial than comments on existing blog posts.

For me the most important item is 1.

On a separate note, I realized it would be fun to have our $n$-Wiki be an extension of the $n$-Category Café ‘brand’. Some bookstores in the US have cafés. So, maybe we could call our wiki ‘The $n$-Category Bookstore’, or ‘The $n$-Category Reading Room’, or something like that. I can’t think of the perfect phrase, but the imagery is something like this: people could leave the Caf&ecute; and do some reading, or writing… then when they get lonely they could come back to the Café and chat.

This suggests, by the way, that the Café is the place for ‘chat’.

Posted by: John Baez on September 6, 2007 7:44 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

I am having a little trouble seeing how and why we can and should determine beforehand what exactly the nature of the entries there will be.

If there is in each entry the possibility to enter text, formulas and hyperlinks, then that seems to allow me to do all or any of what you list: write a mere definition to be linked to from elsewhere, write a long expository article, or whatever.

For me the most important item is 1.

That’ll be fine with me. But, as I said, I can’t quite see how setting up a Wiki supposed to serve one of these purposes would prevent us from using it in some of its corners for any or all the other purposes.

For instance, people here have argued that Wikipedia is not well suited for learning something since it is lacking expository background information. Now, it seems to me that nothing about the technology Wikipedia is running on prevents anyone from typing a nice long expository background article into it. Rather, what prevents people from doing this is the general policy of Wikipedia, which demands that it’s like an encyclopia.

So I don’t see the problem in the technology.

I’d rather say: if and when you think you have found the suitable wiki-flavour for what you find most important about an $n$-Café wiki, don’t hesitate but set the thing up. Then we’ll see what happens.

Posted by: Urs Schreiber on September 6, 2007 7:59 PM | Permalink | Reply to this

### Choices

I am having a little trouble seeing how and why we can and should determine beforehand what exactly the nature of the entries there will be.

Because deciding on what software to use is strongly dependent on what features are important to you. That, in turn, depends on what you are hoping to do with it.

Before settling on Instiki, I considered a bunch of different Wiki software packages. I evaluated MediaWiki, Zwiki, TiddlyWiki, MoinMoin, and a couple of others that I forget. Eventually, I decided that Instiki was the best suited to my purposes (a collaborative research Wiki).

Since I was interested in a research Wiki, one of the features that was important to me was the fact that any page can be exported to LaTeX, at the click of the mouse.

I have frequently availed myself of that feature: I’ve written a couple of papers and one grant proposal by working with my collaborators on the Wiki, and then exporting the finished product to LaTeX. It has worked amazingly well. So, as a “research wiki”, there’s one strong argument for that piece of software.

I can perfectly well see where any one of the above four would be better suited to someone else’s purposes.

The robot features, that Blake used extensively to gather the information for the EUREKA site, made MediaWiki the natural choice for that project.

I can see other cases where ZWiki or MoinMoin would be a good choice.

It really does depend on what you want to do.

Posted by: Jacques Distler on September 7, 2007 4:51 AM | Permalink | PGP Sig | Reply to this

### Re: Choices

It really does depend on what you want to do.

Okay, I get it. Thanks for your patience with me.

All right then, this convinced me: I would want to have the kind of collaborative research Wiki that you have.

Is that incompatible with John’s desire to have a electronic textbook Wiki?

Posted by: Urs Schreiber on September 7, 2007 11:16 AM | Permalink | Reply to this

### Re: Choices

I love all the work that Jacques has done to integrate LaTex, blogs and “iki’s” of various flavours and descriptions. Instiki is great - math is so easy to do. I have also learnt a lot from Musings . I just have two comments :

(a) Is it just me, or is it real slow ? It annoys me sometimes; I want to preview my post but then I imagine those painful 20 seconds when I must wait for the server to respond, and my stress builds up a bit. I don’t know if this is the server, Instiki, or me.

(b) Sometimes when your post has tiny things wrong like not being incredibly careful about line breaks around (blockquote) tags, the incredibly strict parser shouts back at you a little rudely; and due to comment (a) I am ashamed to admit I sometimes find myself shouting back a little rudely too! Often I have no idea what exactly is wrong with my post and I have no alternative but to remove that apparantly innocuous section which is causing the trouble.

Posted by: Bruce Bartlett on September 7, 2007 2:38 PM | Permalink | Reply to this

### Old

(a) Is it just me, or is it real slow ? It annoys me sometimes; I want to preview my post but then I imagine those painful 20 seconds when I must wait for the server to respond, and my stress builds up a bit. I don’t know if this is the server, Instiki, or me.

Golem is my desktop machine, and it’s old. If anyone wants to spring for one of them fancy new Intel Mac Pros, I’m sure it would be much faster.

Paradoxically, the delay you sometimes experience in posting comments to this blog is not necessarily related to the blog software itself, but rather to delays in sending the notification email to the author (which, currently, is done synchronously).

One of the things I intend to fix, with MovableType 4, is sending the notification email asynchronously.

As to Instiki, it does slow down somewhat on really long pages (at least, the ones on my private research wikis). Again, one of them fancy Mac Pro’s would help a lot.

(b) Sometimes when your post has tiny things wrong like not being incredibly careful about line breaks around (blockquote) tags, the incredibly strict parser shouts back at you a little rudely; and due to comment (a) I am ashamed to admit I sometimes find myself shouting back a little rudely too! Often I have no idea what exactly is wrong with my post and I have no alternative but to remove that apparantly innocuous section which is causing the trouble.

Instiki is much less rude than this blogging software. It will gamely try to make sense of whatever you have written. Such is the wisdom that comes with experience.

Posted by: Jacques Distler on September 7, 2007 3:29 PM | Permalink | PGP Sig | Reply to this

### Re: Old

Hi Jacques,

I am embarassed to reveal that I thought the n-category cafe was running under Instiki. I guess all the “iki’s” have amalgamated in my mind into some kind of horrible blob of confusion.

Anyhow, I think you knew that. Your explanation about the synchronous email system being a prime cause of slowness makes a lot of sense - it explains why, occasionally (not very often), one has to wait for ages before the n-category cafe accepts a post.

By the way, I am impressed by this new slideshow ability you have over on Musings.

A feature request (which I’m sure has come up many times before) : it would be really great to have the XY-pic package so we can do \xymatrix commutative diagrams.

Posted by: Bruce Bartlett on September 7, 2007 11:59 PM | Permalink | Reply to this

### Re: Old

I am embarassed to reveal that I thought the n-category cafe was running under Instiki.

Just so everyone is on the same page:

• My blog and this one run on a heavily-hacked version of MovableType. We’re currently running version 3.35 because I have not had a chance to think about porting my changes to MT4, yet. Sometime this Fall, MT4 will be released as Open-source and I will finally be free to distribute a version with all my enhancements rolled-in. All I need is an extra day of the week to devote full-time to hacking on MT.
• Instiki is my Wiki software. It’s already Open-source, like the project from which it was derived. The original focussed on ease-of-installation (“There Is No Step Three™!”) My focus is on adding the features that make it useful for research collaboration.
• To that end, Wiki pages in the category “S5-slideshow” are slideshows. I like the fact that you can create a quite professional-looking presentations using the same Markdown+itex syntax you are used-to from the Café — right there in the Wiki.

In addition to the items on the TODO list, there are a few other things I have planned for Instiki (like a LaTeX-compatible scheme for doing references). Suggestions are welcome. Contributions of code are even more welcome. That’s why the code repository is in Bazaar.

A feature request (which I’m sure has come up many times before) : it would be really great to have the XY-pic package so we can do \xymatrix commutative diagrams.

I’m always interested in extending itex. The main barrier, in this case, is the expressiveness of MathML. At some (rather fuzzy) point, one would want to switch over to SVG.

But, as a category-theory afficionado, I would have thought you would lobby for dcpic.sty!

Posted by: Jacques Distler on September 8, 2007 2:46 AM | Permalink | PGP Sig | Reply to this

### Re: Old

Bruce wrote:

I am embarassed to reveal that I thought the n-category cafe was running under Instiki.

I was wondering what you were thinking. You — and everyone! — should try out Jacques’ version of Instiki. Note: to edit pages, go down to the bottom left and click on Edit; to see what the page would look like in TeX, click on TeX.

Here’s a question. I already have a website at UCR: a directory in the math department UNIX machine where files in that directory mysteriously become visible to everyone in the whole world if I set permissions correctly. I think it uses Apache, but I say “mysteriously” to emphasize the fact of my fundamental cluelessness about this sort of stuff.

I’m wondering if a clueless user like myself can just sort of stick Instiki in this directory and get a bunch of Instiki-formatted webpages to appear to the world. It looks like the answer is no: it looks like I need to “create two VirtualHost sections in my Apache config file”. But maybe that’s only if you don’t already have a directory set up that’s designed to be a website?

Posted by: John Baez on September 8, 2007 10:47 AM | Permalink | Reply to this

### Re: Old

Instiki is designed for super ease-of-setup. So, by default, it runs on port 2500, with the built-in WEBrick webserver. You don’t need Apache or anything.

Trouble is

1. All your URLs have an extra “:2500” appended to the hostname.
2. In some places, port 2500 may be firewalled, so you won’t be able to reach your Wiki from the outside.

The next easiest thing to do, if you do have an Apache webserver, is to have Apache proxy your instiki wiki(s). They then appear to be part of the normal URL hierarchy of your website (served by Apache), even though they are “really” still on port 2500, served by WEBrick. (This also gets around the firewall problem.)

Proxying makes two different webservers appear to function as one.

“Virtual Hosts” does the opposite thing: it allows a single Apache webserver to host two different websites, with distinct URL hierarchies, on the same machine.

Posted by: Jacques Distler on September 8, 2007 3:29 PM | Permalink | PGP Sig | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Urs wrote:

I can’t quite see how setting up a Wiki supposed to serve one of these purposes would prevent us from using it in some of its corners for any or all the other purposes.

Certainly nothing prevents it, but there are many different kinds of wikis, which are good in different ways. We’re trying to pick one. There are also other decisions to make. To make these decisions, it helps to know what’s most important to us!

Other less important things will still be possible: they’ll just be suboptimal.

For example: do you mainly plan to include links to PDF files of papers, or do you want to actually write pages including equations?

If you plan to write pages including equations, can you tolerate ugly-looking equations like this, which require you to write stuff in this format? If so, MediaWiki would suffice. And, as Chris Hillman emphasizes, MediaWiki has the advantage of familiarity.

There are lots of other questions, but these are a couple. Your opinions matter, because you are the most likely to contribute enormous amounts of material.

Posted by: John Baez on September 7, 2007 11:47 AM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Okay. Sorry for my unproductive remarks so far. I was scared that by demanding the optimal we would end up with the impossible and hence miss the suboptimal but possible.

The optimal desideratum for me is: a collaborative research Wiki, which is an alternative to sending pdfs around.

I am dreaming of a Wiki where we do the technical (non-chat) things we already do on the Café, just in a more suitable environment.

So I want it to include expository background material (like in this entry) which somebody happens to want to write up, optimally lots of such, like the entire monographs containing your various Tales.

But I want it to also be a place to develop ideas, the way we did with David Roberts and Todd Trimble for instance, recently, in the comment section here. Currently David, Todd and myself are circulating a LaTeX source among us, which we keep incrementally improving. This is the thing I would like to instead do on the Wiki.

In general, I imagine a place where we don’t heap posts on top of each other but gradually refine and evolve the existing material to ever greater heights of perfection (ahem).

I am completely enchanted by what Jacques said: that he is able to take his research Wiki and make it spit out its material in the form of papers. That sounds fantastic: we could keep fiddling around on that Wiki, and when something happens to have evolved into a solid finished thing, we turn it inot a traditional document and send it out to the unWiki-fied world.

Posted by: Urs Schreiber on September 7, 2007 12:07 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

I too would greatly value the ability to develop something on a Wiki — possibly with heavy collaboration or possibly just with the ability to have people look at it and make comments and corrections — and then turn it into LaTeX and publish it.

So, we sound agreed on that.

The equations on Instiki look nice. I guess there’s the problem of wanting to use lots of diagrams… I see a nice Feynman diagram there…

Posted by: John Baez on September 7, 2007 12:15 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

I guess there’s the problem of wanting to use lots of diagrams

Jacques’ Instiki supports the same MathML as we have here, hence the same kind of diagrams obtainable that way. (I just checked by adding one to his Sandbox. Hope that’s okay.)

For larger diagrams, I’d guess we’d include xypic and the like into the Wiki for instance the way I commonly include them here: I produce a gif from my LaTeX source using TeX to GIF.

Posted by: Urs Schreiber on September 7, 2007 1:10 PM | Permalink | Reply to this

### Drawbacks

In fairness, let me tell you some of the things that Instiki does poorly. Some things are on the TODO list. Others are just features that are better handled by other Wiki software.

Access Control
ZWiki is the champ, here, with very fine-grained access controls as to which pages are visible to whom, and which pages are editable by whom.

MediaWiki is somewhere in between. But Instiki is positively primitive.

• It has no concept whatsoever of registered users.
• It has no concept of controls on individual pages.

Instead, you can create multiple “Webs” (Wikis) under one installation, and all of the pages in a single “Web” have the same access control. A Web can be

3. Wide open: anyone can read or edit any of the pages on that Web.
Revision History
All wikis provide you with the means to look back at previous versions of a page, compare different versions, and “rollback” a page to a previous version. MediaWiki provides each page with a detailed “History”, and you can compare two arbitrarily chosen versions.
Instiki lets you page back through the revision history of a page by clicking (repeatedly) on the “Back in time”/”Forward in time” buttons. And you can only compare two successive version (the nth and (n+1)st).
Page Management
Zwiki has wonderful fuzzy-URL-matching, MediaWiki has disambiguation pages. Instiki has none of these. It doesn’t even really have a facility (adding one is on the TODO list) for deleting a page, once created. You can remove all links to a page, and then delete “Orphaned” pages (pages with no Wiki-links to them). But that’s a kinda crude tool.
Prerequisites
Zwiki is the worst, here, requiring a Zope server on the back-end.
Instiki requires Ruby (>1.84), the SQLite3 Ruby bindings and SWIG (required to compile the itex2MML Ruby bindings).
MoinMoin requires Python.
MediaWiki requires PHP and mySQL, which any Webhosting firm will have. (To be fair, if you want equations, then it will require a full TeX back-end, dvipng, OCaml (>3.06), etc., which most webhosts won’t have.)

I’m sure there are other areas where Instiki is a poor choice, but those are the main ones, that occur to me.

To answer your question about figures: Instiki does have file upload facilities, for images or PDF files or whatever. And (if you’re brave) you can include inline SVG, just as you can on this blog.

But MediaWiki, for instance, does have more extensive facilities for managing uploaded resources.

Posted by: Jacques Distler on September 7, 2007 3:09 PM | Permalink | PGP Sig | Reply to this

### Re: Drawbacks

LOL.

My local radio station here in Hamburg greets me with MoinMoin. Maybe that should make me opt for this Wiki…

Posted by: Urs Schreiber on September 7, 2007 3:16 PM | Permalink | Reply to this

### moinmoin

If I were to start from scratch with what’s available right now, I think MoinMoin+jsMath would be the best choice for your purposes. Here’s a sandbox:

somebody’s moinmoin+jsMath page

Python is a good language, and moinmoin is open source and uses a flat file storage system. The jsMath addition looks pretty easy.

Of course, personally, I’ve spent a lot of time pulling my hair out tweaking tiddlywiki javascript, and I’m happy with the result. But it’s not good for collaboration yet.

Posted by: garrett on September 8, 2007 4:06 AM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Urs said:

In general, I imagine a place where we don’t heap posts on top of each other but gradually refine and evolve the existing material to ever greater heights of perfection (ahem).

OK, I now understand where you are coming from and I completely agree. This would be great. We could then have the latest results of a discussion as a kind of central focus point, with further exposition of the material in it sited in peripheral articles hanging off it. And of course we could also tie in to the history of the discussions about that particular topic on the Café, and see how we got to where we are with it.

Posted by: Tim Silverman on September 7, 2007 10:09 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

We could then have the latest results of a discussion as a kind of central focus point, with further exposition of the material in it sited in peripheral articles hanging off it. And of course we could also tie in to the history of the discussions about that particular topic on the Café, and see how we got to where we are with it.

Yes!

Discussion on the Café, evolving results of such dicussion (of whatever form: definitions, expositions, insights) on the Wiki.

Posted by: Urs Schreiber on September 8, 2007 1:13 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

I think a wiki is a great idea.

One possibility is to make it more like a wikibook than a chunk of wikipedia, i.e. still highly interlinked, but also with an linear structure on top.

Wikibooks is still in a fairly primitive stage at the moment, but I think shows the great promise of collaborative textbook writing. See, for example, the wikibook on LaTeX.

Posted by: Ben Webster on September 3, 2007 5:05 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

John wrote:

The very thought of writing another makes me feel tired, not energetic. It’s such a solitary pursuit, and the payoff comes only after so much labor. The whole idea of books is looking a bit old-fashioned. A wiki, on the other hand, is a communal enterprise. And, it’s fun from the very start!

This exactly captures my own feelings when I contemplate creative activity, but there are many other reasons to prefer a wiki, some of which I obliquely hint at below.

Generally speaking, we should expect the new site to develop in ways we have not anticipated, so we should try to ensure at the outset that we are prepared to deal with that gracefully. For this reason I advocated spending some time discussing “wikigovernance”. I will suggest a very simple way to minimize but not eliminate the time spent on developing a flexible but clear “wikiconstitution” and also avoiding endless headaches thereafter.

I am very glad that both Blake and Garret have offered to help set up the new website, and I am heartened to see that most of you seem to recognize that this offers a wonderful opportunity to reconsider the reshape the cafe into something completely different and hopefully far superior. I think it is reasonable to expect the new site should immediately foster goals including but limited to helping John develop his long-awaited next book. But I am concerned that several posters are heading down the same path which caused trouble with the current cafe.

I’d like to urge you all to think in terms of striking a wise balance between conflicting desiderata, as you plan the new website.

My most important and least negotiable desideratum may unfortunately prove most controversial:

I strongly believe, for a whole host of reasons, that edits to the new website should be stringently restricted to a small and select “invisible college” with new members occasionally elected by existing members, with the original membership being the John, Urs, and David. This does not preclude allowing other individuals from leaving comments or questions on certain pages having especially lax permissions, provided that they are willing to “register a comment account subject to our verifying your IRL identity”. Nor does it preclude eventually constructing a more elaborate scheme of permissions enabling a larger group to do more things at the website.

My (reluctant) insistence on this point will probably horrify many here, so let’s just leave that hanging for a moment and immediately pass on to some further examples of possibly conflicting desiderata:

Some things we want to ACHIEVE:

• easily learned markup (I dare say we all already know both MediaWiki and LaTeX markup!)
• easy and flexible inclusion of mathematical equations, tables, and figures (all of which standard MediaWiki does superbly, IMHO, AFAIK).
• easy and flexible internal and external links (compare pasting urls into a wik and bracketing them with making a link in standard html)
• easy and flexible organization (MediaWiki categories are easy to learn and use; I hope that future editions will enable graphic visualizations but we could easily provide our own jpeg figure showing basic organizational structure)
• site should be (mostly) world-readable but certainly not world-writeable (I am told that MediaWiki allows for flexible global permissions)
• easy way for general public (but not IP anons) to leave comments in “comment space” (I am told that MediaWiki allows for flexible permissions applied page by page)
• easy way for general public (but not IP anons) to “ask an expert” a question on n-categories
• easy webform for applying to register an account, with clear rules for who is allowed to register an account
• easily found, clearly written, morally elevated but not unrealistically idealistic (a) statement of purpose (b) privacy policy (c) wikiconstitution, and (d) behavioral rules
• easy editorial oversight, reasonably uniform and attractive appearance/style of public articles
• easy maintainance
• foster cautious but responsible exploration of possible technical innovations above and beyond standard MediaWiki (bearing in mind all conflicting desiderata)
• stick close to the tried and true

Some things we want to AVOID:

• allowing any anon edits whatsoever, in fact I would strongly prefer to restrict registered accounts to entities whose true identity is known and whose good judgement is well established; I feel so strongly about this that I myself would be willing to forgo registering and account myself if others would accept a rule preventing trolls or sockpuppets from messing with the website, e.g. by stating that “verifiably identified persons only”, in fact “tenured faculty only”, can request an account— my thinking is that it is rare for people to attain professorship or even graduate studentship at accredited institutions unless their academic credentials have been vetted, or having their existence and unicity verified)
• compromising security of the website itself (e.g. by trying to shoehorn in some buggy code; anything which requires Javascript might be suspect)
• any technical innovations requiring either a reader or contributor to install something on his own computer, or to extensively change his browser settings, or anything potentially compromising security of the user’s computer, without a very good reason; indeed, the working assumption should be that the default user has tight browser settings; ideally, anyone should be able to read public pages with very tight browser settings, and if someone who has registered a comment account and who uses Firefox to enable “session only” cookies from the new website, should be able to comment in public areas of the website; enabling javascript or popups or inherently insecure code should not be neccessary for casual interaction with the new website
• anything at all tending to make it easier for trolls, vandals, or well-intentioned but overenthusiastic ingoramuses to disrupt the website
• anything at all which tends to create unneccessary technical obstacles for either contributors or readers
• chaotic mix of notation and style
• time consuming maintainance, getting bogged down in technical issues
• getting bogged down in developing experimental and possibly buggy code; radical technical innovations should be avoided unless there is a strong rationale for risking them,
• getting bogged down in “wikigovernance”

Let me expand on the issue of “wikigovernance”: IMO, the lamentable example of Wikipedia shows very clearly that the single most important thing one must do to minimize the time spent on wrestling with wikigovernance is also one of the easiest: forbid anon edits, period. That is, forbid any edits by unregistered users, and require that applications to register an account have verifiable identities (most easily achieved by requiring that they have e-verifiable affiliations).

This is one reason why agreeing at the outset on a common and clearly expressed vision at the outset is so important; I am not kidding when I use the term “wikiconstitution”, a term intended to suggest a clear an unambiguous framework for resolving unexpected future issues with a minimum of fuss). I feel that initially restricting edits to a small and trusted group would essentially eliminate any governance headaches, but it should be easy to provide a world-writeable comment page (I’d advise stating that if it is abused, the maintainers reserve the right to block anyone or even to stop reading it if it becomes a timesink).

Another set of considerations to bear in mind: the new website would among many other things comprise, would we will it or no, one more scholarly response to the endemic and apparently incurable quality control problems at Wikipedia. So let me add a few words about the prospect of competing with Wikipedia, in some sense, for the attention of search engine spiders and those seeking mathematical/scientific information.

I have long stated that IMO attempts (e.g. Citizendium) to compete “head-to-head” with Wikipedia are unlikely to succeed. Rather, I have advocated creating small highly specialized wikis, perhaps combining exposition and research material, created and maintained by small groups of genuine experts (typically, tenured faculty members) who know each other personally and share a common vision. I have argued that the proper role of massive “universal information resource” websites should be to aggregate reliable information from such specialized encyclopedias.

At present, the best example of what I have in mind may be Scholarpedia. Another model (also boasting Terry Tao as a contributor) which seems well worth examining is DispersiveWiki. Note that the denizens of this wiki have taken advantage of wiki’s flexibility to make annotated bibliographies, to write expository articles which should help graduate students understand the importance of the subject at hand, and so on. I think this website, while still very young, provides a good hint of what I have in mind. (Unlike Scholarpedia, it seems that DispersiveWiki follows the traditional wiki model of being both world readable and world writeable, which I feel is a terrible mistake.)

So, one possible “spinoff” would be the creation of a small highly specialized encyclopedia on categories, or even just on n-categories. This could happen naturally via the creation of expository articles on topics such as “gerbe”. Perhaps David Corfield could be persuaded to switch fields and to create a small highly specialized encyclopedia on philospophy of statistics. (No? Well, it was worth a shot!) Perhaps I could be persuaded to try to resurrect my hoary old “Categorical Primer” in the form of a set of expository wiki articles. Should these possibilities come to pass, it would well worth taking the time to look into how one requests sites like answers.com or wikipedia.org to auto-aggregate articles from the new site, how one can get it listed at yahoo, and so on.

Coming back to the troublous question of who would be allowed to edit the new website: unfortunately, limitations of time, energy, space, and a certain desire for personal safety, all preclude me from attempting to even sketch my concerns about manipulation of information except by setting up my own “protected wiki” collecting links to on-line newspaper articles, case studies using Wikiscanner, and so on. In lieu of such a sketch, I hope everyone here will accept that as a highly experienced Wikipedian (at one point I was in the top 500 most active contributors) who has also participated in various other public forums for a long time, I am all too familiar with the prolixous and sometimes subtle ways which nasties have invented in order to promote a hidden political or financial agenda by taking advantage of the scholarly tradition of Assuming Good Faith. Life would be so much simpler if we could operate under that assumption! At the risk of beating a deceased equine, I reiterate: by limiting editing of “best articles” to a small group of known and proven-trustworthy contributors, the new website probably COULD operate under that assumption, to a great extent, at least initially.

One point I’d like to stress is that, if the maintainers are willing to accept the risk of a timesink should this not prove straightfoward to implement, it should be possible to eventually grant a range of privileges to different registered users, and also to impose a range of restrictions on individual pages at the new website. For example, I tend to feel that “approved articles” should be world readable but only writeable by a very select group, while internal discussions could be readable only by registered members. My experience at other forums suggests that there will be a need for private discussion of sensitive issues, but for a small and highly focused website this could probably be handled by email among a core group of maintainers who all have registered GPG keys.

I note that restrictions need not be enforced within MediaWiki but can and probably should be reinforced by such simple steps as write-protecting certain directories at the level of the operating system (it goes without saying, in this crowd, that the operating system will be unix or linux). If some of what I suggest above sounds like SE-linux, well, some way this is much easier to use now than it once was, but there are alternatives which are even easier. But as I stress again and again, simply enforcing settings which forbid edits execept by registered users will go a very long way toward protecting the new website from the timesink of reverting vandalism, dealing with cranks and trolls, and so on (and on and on and on).

(If anyone here doubts that trouble invariably finds any well-regarded website offering “good stuff”, ask just Blake about wikishilling PR flacks! We all need to accept that, as experience shows very clearly, the more highly regarded a website is, and the more respected its information/judgements, the more likely it becomes that baddies will try very hard and very persistently to infiltrate and subvert it.)

Making the new site appear friendly while insisting, gracefully but firmly, on strict rules for who can do what, requires a rather delicate balancing act. But you (we?) don’t really need to explain in detail why you (we?) have strict rules, since it would be your (our?) site.

As some of you already know, I have not been able to participate in the Cafe because the Cafe has violated several of the considerations outlined above. I feel so strongly about the neccessity of imposing strict rules on who can edit (at least, who can edit public pages the new site stands behind) that I’d be willing to forgo my own participation if crafting clear and simple “rules for participation” which would allow me but not trolls, vandals, cranks, and otherwise disruptive users should prove difficult. This wouldn’t preclude my sharing, as an exemplar, the style manual I created for the defunct WikiProject GTR in Fall 2005.

I dare say that all of us, or almost all of us, are strong advocates of the “Open Access” movement, and also of what has been called the “New Enlightenment”. As such, we probably tend to strongly favor empowering the ordinary citizen, and we may well be attracted by some elements of the venerable tradition (in American politics) of populism. Nonetheless, at Wikipedia (before my user pages were vandalized out of existence), I tried to argue that scholarly ethics are unintentionally but ineluctably elitist and thus in direct conflict with populist ethics.

But let’s not lose sight of the simple principle underlying all of my suggestions above: knowledge is power. In the long run, the best way academic experts can empower ordinary citizens is by ensuring that their expert knowledge, advice, and judgement is made freely available to the public, while also ensuring that their time is not wasted dealing with trolls, vandals, kooks, wikishills, legal threats from malcontents, and assorted other disruptive forces.

Lest any of these considerations should seem daunting or even discouraging, I stress again that by far the simplest way to avoid headaches is to restrict editing to a small and trusted group, at least initially. This bit of wisdom runs directly counter to the original vision of the wiki, but I trust the energy and enthusiasm of the core group will prove that wikis can be usefully employed in a much less naive fashion to develop a truly valuable public and scholarly resource.

Last but not least, John wrote “The Higher-Dimensional Wiki (or whatever we call it)”. My own suggestion (and I’m surprised that no-one has beaten me to it!) is “Weekipedia” :-)

Posted by: Chris Hillman on September 4, 2007 10:01 AM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

There’s a lot to reply to here, but I’ve got to run off and give a talk. So for now, just a wisecrack! Chris wrote:

So, one possible “spinoff” would be the creation of a small highly specialized encyclopedia on categories, or even just on n-categories.

Surely he meant “on n-categories, or even just on 1-categories”.

Posted by: John Baez on September 4, 2007 10:16 AM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Indeed, that’s a great deal of information and insight to consider. I’m also pressed for time (man, what is it with the folks around here?), so for now I’ll restrict myself to a technical comment.

It is easiest to restrict page access in MediaWiki on a namespace basis. At EUREKA, for example, you’ll note that we have articles, discussion pages, user pages, user talk pages and so forth. Right now, the wiki is configured in such a way that pages in each of these namespaces are world-readable but writable only by logged-in users. It would be easy to create additional namespaces, such as “Forum” or “Feedback”; we could also create additional castes of users, such as “wikitenured faculty”. Perhaps EUREKA pages on journals could only be edited by the latter, while discussions could accept edits from all registered users. A similar scheme could be applied to Weekipedia: Articles proper can only be edited by wikitenured faculty, i.e., the hosts of the Café and those they choose to beatify. Forum pages (possibly distinct from the talk pages associated with each article) can be edited by any registered user.

Posted by: Blake Stacey on September 4, 2007 6:11 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Hi all,

I’ve been having trouble posting here, but we’ll see if this works.

I don’t think I made myself sufficiently clear, so let me try to add some additional “framing”.

My contention is that we need to proceed like this:

* decide upon and clearly enunciate the mission(s) for Weekipedia (fostering John’s next print book, provided example of how to replace the academic tradition of publishing scholarly books with maintaining a scholarly wiki, test platform for experimental wiki software? for experimental math rendering?)

* priorize our list of competing desiderata, in a manner appropriate to our shared vision of the mission of Weekipedia,

* choose the initial software platform.

As John stated in the initial post, after a year of operating the Cafe under Jacques’s software, the time has come to consider to migrating to a different engine. This suggests that we should expect future migrations, whatever decision we make now.

Add to my list of competing desiderata:

Some things we want to ACHIEVE:

* portability

* anything which tends to lessen future work if, as seems likely Weekipedia eventually migrates to yet another software base in future

* speedy math rendering

* modest file storage requirements

Some things we want to AVOID:

* software “solutions” peculiar to one operating system or one browser, or which work very nicely for one OS or browser but very badly for some common competitors

Let me add a few thoughts on the issues of enunciating a mission, priorizing desiderata, and choosing a platform.

I feel that Weekipedia should most definitely NOT serve as an experiment in the latest math rendering or wiki software. I feel that the primary mission should be promoting the study and appreciation of n-categories, or categories generally (John said “less generally”, but I still see n-categories as merely one possible offshoot of “category theory”), with secondary goals of challenging traditional modes of scientific discourse and publication, fostering Open Access. As Garrett said, the feature which makes wikis the only sensible choice here is the ease of linking externally and internally.

Given this, I think it makes sense to give more priority to a solution which is known to be workable, which we can expect to use over the next year or two to support Weekipedia. Also, I think Weekipedia need not shoot for state-of-the-art math rendering or file systems; it probably makes more sense to shoot for the least ambitious rendering and file system which will meet the needs of the site. Making an attractive and easy-to-use site is indeed very important, but we need to balance this against the need to minimize the likelihood of getting bogged down in technical issues and the need to start making a useful site immediately.

Given this, overall, I think MediaWiki still is pretty much the only sensible choice at this point in time.

I agree with those who feel that MediaWiki has many shortcomings and who wish to encourage the development of better alternatives. However, I feel that the best way to do that is to build a model wiki under a platform like MediaWiki (the Devil We Know, as it were), and to challenge developers to show us a better way to do what we are doing under MediaWiki. (If that’s not inverting metaphors: how does one work “under” a “platform”?)

IMO, jsmath is nice but too slow, and this is unlikely to change. In addition, I feel that avoiding Javascript, especially experimental Javascript, is a good idea from the security standpoint (especially bearing in mind that many readers will probably be using Explorer, and it is very much in the best interest of Weekipedia to avoid enticing phishers to try to insert malicious trojans onto the site, as is reportedly the latest trend in organized webcrime).

I’d add that I see no reason why MediaWiki could not be the engine for the primary Weekipedia site, but we could contemplate Jelsoft software (see http://www.physicsforums.com/) for a “comment area” which combines reasonably capable math rendering with an easy markup syntax which is quite similar to MediaWiki and LaTeX markup.

Posted by: Chris Hillman on September 6, 2007 7:07 PM | Permalink | Reply to this

### Structure of Wikispace/Cyberspace is on-topic; Re: Toward a Higher-Dimensional Wiki

I agree with many of Chris Hillman’s comments. “Platform” is loosely used to mean combinations of user’s computer hardware, operating system/version, browser, plug-ins, and the like. Smart server-side software can learn quite a lot about the user’s platform, but it’s difficult to respond appropriately (speaking as a former Documentation Manager of Web Services at EarthLink).

(If that [is] not inverting metaphors: how does one work under a platform?)

To adjoint the metaphor, I thought of both the times that I’ve been technically beneath a theatrical stage (orchesra pit, trap door, and the like) and as a delegate to a political convention, where there is proceducral debate underlying the substantive debate on the Party Platform.

I’m not trying to be off-topic. The notion of “platform” and orientation in cyberspace, up and down, above/below, are relevant as we are discussing the substrate of cyberspace and wikispace and literature-space and equation-representation spcae and category diagram representation space as some kind of morphisms or natural transformations or fibrations of physical (meat) space-time.

I’m deeply influenced by my early 1970s work with Ted Nelson, inventor of hypertext, who insists correctly that it’s a mistake to use cyberspace to simulate 2-D paper documents. He has unpublished work on very interesting alternate coordinate systems, bizarre in noneuclidean nature, but that quickly gets off-topic.

Posted by: Jonathan Vos Post on September 6, 2007 7:40 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Chris writes:

As John stated in the initial post, after a year of operating the Cafe under Jacques’s software, the time has come to consider to migrating to a different engine.

Hmm. It depends what you mean by ‘migrate’.

I don’t plan to leave the Café, which (for all of us except you) is working very nicely for its intended purpose: talking about math, physics and philosophy.

What I plan to do is expand our activities to include something that more resembles a collection of books, papers and reference materials.

So, I don’t want to ‘migrate’. I want to take over more territory.

Posted by: John Baez on September 7, 2007 11:55 AM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

JB said

I don’t plan to leave the Café, which … is working very nicely for its intended purpose: talking about math, physics and philosophy.

Indeed, the fact that we want to set up a Wiki is a sign of how successful the Café has been—we’ve generated so much material (OK, mostly Urs has … :-) but we’ve all tried!) that it needs to be collated and organised somewhere. Generating lots of material —which people are anxious about losing!— is a good thing.

Posted by: Tim Silverman on September 7, 2007 10:48 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Tim Silverman wrote:

but we’ve all tried

Indeed. One of the first things I would like to enter into the-Wiki-to-be is your work on Euler characteristics of non-finite categories. That’s precisely the kind of stuff that deserves not to be forgotton somewhere in some long comment thread.

Posted by: Urs Schreiber on September 8, 2007 1:28 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Wow, thanks!

I’m still thinking about this stuff on and off when I get the time, so maybe at some point I will have something more to report, hopefully more concise and intelligible.

Posted by: Tim Silverman on September 10, 2007 9:05 PM | Permalink | Reply to this

### The Category of Wikis

The art of making a good wiki is in crafting the pattern of links. This activity should be natural to the category of mathematicians, so I probably don’t need to say anything – but I will anyway, in the hope that someone else will figure this out properly.

Each wiki entry will have some math in it. This math will include objects and relationships established in other entries – so there should be wiki-links to those other entries. I think this is a kind of morphism between wiki entries? (As a natural consequence, the other entries automatically have “forward-links” to where they are referenced – this is what makes a wiki better than a web page.) Now, if you’re building up your links properly, you’ll get patterns of wiki entries that are linked up similarly, reflecting the same mathematical structures being developed with different objects and text. I think this means there are functors between the collections of wiki entries? Anyway, I’m hoping someone here can think about this meta-relationship more clearly than I can, but it’s certainly in my head when I work on mine. You might be able to think of a wiki this way, from a mathematical perspective, and come up with a powerful new way of building and presenting mathematics from a categorical perspective.

Posted by: garrett on September 4, 2007 9:32 PM | Permalink | Reply to this

### Re: The Category of Wikis

Heh, that last sentence was from the department of redundancy department. It should have read:

“You might be able to think of a wiki this way, from a categorical perspective, and come up with a powerful new way of building and presenting mathematics.”

The best feature of wikis is that you can edit them. ;)

Posted by: garrett on September 4, 2007 9:48 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Congratulations everyone on the first year! Even as a defunct computer scientist (read: employed in financial industry) I’ve gained a lot in my time lurking here —- I love this place, despite spending a lot of time befuddled.

I’ve had a reasonable amount of experience with wikis in the corporate domain. My advice for minimizing headaches is to be mainstream, which (even for sophisticated users like yourselves) would mean Mediawiki, or perhaps the modified version that uses blahtex (this is the demo wiki) if you all dislike TeX graphics so much.

I think the wikibook format would be an excellent way for you all to start. That way you could avoid the urge or need to feel boring/encyclopedic. Wikipedia is amazing, but learning math there compared to here? Forget it! I think the Haskell wikibook is a nice example:

Note the three tracks (beginners, advanced, applied): a format like that could work especially well in the hands of cafe contributors.

Finally, keep it simple stupid (*yay* I get to call n-category experts that): collate the best advice you receive, make some judgement calls, and learn on the job by getting something up and running. Very easy to get bogged down in minutiae with this sort of thing, and too many restrictions can lead to still births and/or lame-duck-wikis… there’s nothing sadder!

I also strongly advise being open. How many trolls on the Haskell wiki-book site? Next to none… yet I’m guessing their community is larger than the one here, and computer languages are more powerful troll-bait than higher dimensional algebra (right?). I’m guessing you have the man power to manage, and if you find later you don’t then would be a good time to start thinking about tying things down, or (> 3 line) constitutions.

Posted by: Allan E on September 5, 2007 6:07 AM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

A couple more things:

- by “being open” I don’t mean allow anonymous changes (registration, even lightly vetted, isn’t so demanding on guests/maintainers); I just mean an “experts only” attitude may put off beginners like myself from contributing to appropriate “beginners”/expository material

- by recommending Mediawiki I’m not suggesting it is without problems; as a piece of software it is actually quite weak, and near impossible to improve in a modular fashion (compared to say Plone or Rice’s Connexions project (also based on Plone, with strong MathML support). The problem with more high-tech products is they often don’t use standard wiki or html formatting, so can involve a learning curve for your users: no-one ever got fired for using Mediawiki (if you’re worried about being fired!)

- John Langford recently asked some thought provoking questions on what’s missing from online collaborative research on his machine learning blog

Best of luck with this! I think it’s a great idea

Posted by: Allan E on September 5, 2007 3:37 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Two quick useful items: A friend pointed out to me this site:
Texify
, which really does a fine job of taking any equation in LaTeX and giving you the html code for it.

Also, the wiki
Knot Atlas
, (mentioned earlier, created by Dror Bar-Natan and Scott Morrison) is back online and still a great example.

Posted by: Stefan on September 6, 2007 4:16 PM | Permalink | Reply to this
Read the post Lie n-Algebra Cohomology
Weblog: The n-Category Café
Excerpt: On characteristic classes of n-bundles.
Tracked: September 7, 2007 5:59 PM

### Re: Toward a Higher-Dimensional Wiki

So where’s our wiki?

As Jacques’s comparision of different platforms suggests, the alternatives currently available each offers certain advantages and suffers from certain disadvantages. To repeat myself: I have contended that choosing a platform requires making a tradeoff between competing desiderata (not mutually compatible, at least with currently available wiki platforms), and this in turn requires prioritizing them after agreeing upon a misson, or at least a primary mission, for the new wiki.

But now I am concerned that nothing was settled in our discusson so far. Have John, David, and Urs agreed upon a primary mission statement? (This need only apply to the first year or two of operation and doesn’t preclude re-evaluation if the wiki grows in unexpected directions.) If so, is there emerging agreement on prioritizing competing desiderata?

At some point we need to make a choice and create the thing. I have suggested for some time that under most prioritizations of competing desiderata, MediaWiki, for all its flaws, is likely to emerge as the best available platform.

Blake, do I understand that you are in a position to set up a test version of the Weekipedia running under a suitably “tightened” installation of MediaWiki?

Posted by: Chris Hillman on September 17, 2007 6:10 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Chris wrote:

So where’s our wiki?

I said I wouldn’t actually do anything on this wiki until various other things happened. They haven’t all happened yet.

But, while we’re waiting I hope the people who plan to contribute a lot to this wiki reach some agreement as to its basic properties. I hate the way math looks on the Wikipedia, and I love the idea that Instiki can be used to draft write papers in TeX. Urs also seems to love that idea. So, I’m leaning towards giving Insitiki a try. At least a tentative little try, to see if I actually love it or not.

You may hate the fact that Instiki uses MathML.

Posted by: John Baez on September 18, 2007 8:31 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

My remark which started this thread was triggered by the idea that maybe with the EUREKA Wiki already existing, it would maybe take Blake Stacey just five minutes to clone it, change the title to something $n$-categorical and have us see what happens.

While you did succeed in convincing me that investing more time into designs decisisions than that would be worthwhile, I am still worried that

a) without just going ahead and trying it, we may be lacking the experience to make these designs decisions

b) by aiming for the optimal we may end up with the non-existing.

From what I have understood, I got the impression that Instiki would be close to our needs here. But I don’t really know if maybe with MediaWiki I could achieve happiness just as well. I’d rather have an existing MediaWiki than a non-existing Instiki, for sure.

Maybe this points to one interesting question:

suppose somebody breaks down and creates an $n$-category Wiki of whatever flavor. Suppose we start using it, accumulating content. Suppose then, after a while, we find out that we’d be happier with another flavor of Wiki. Then:

how much trouble would it be to transfer the content of one Wiki to another?

Posted by: Urs Schreiber on September 19, 2007 3:14 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Thanks to Jacques for his further comparative analysis, which as I read it confirms my hunch that choosing Instiki over WikiMedia increases the likelihood of unforeseen problems. He also reminded me of an important issue I had forgotten, scalability. (But over the next year I suspect he might be correct in assuming this is unlikely to pose a huge problem.)

Blake, can you comment on Urs’s expectation (which has been my own expectation!) that you could easily create a test Weekipedia running MediaWiki? Jacques, how easy would it be for you to create a competing test wiki running Instiki? It seems these are pretty much the options available due to the expertise of available volunteer labor, and while I value this kind of discussion of foundational issues, like Urs I am concerned that migrating to a wiki not bog down in this discussion.

So, it is time to create two competing test wikis so that John, David, Urs can play with various features?

Posted by: Chris Hillman on September 19, 2007 4:46 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

My remark which started this thread was triggered by the idea that maybe with the EUREKA Wiki already existing, it would maybe take Blake Stacey just five minutes to clone it, change the title to something n-categorical and have us see what happens

Texvc has a whole slew of additional prerequisites that may not even be available (I don’t know) on the webhost Blake chose for the EUREKA wiki.

Turning on math support in MediaWiki is not as simple as just flipping a switch.

how much trouble would it be to transfer the content of one Wiki to another?

In Instiki, exporting the the complete wiki in source-form is a trivial operation. Two mouseclicks gives you a tarball of Markdown files. I don’t know how to export an entire wiki, in source form, from MediaWiki. Maybe Chris can inform us.

However, since the markup syntax is different (Markdown versus MediaWiki and itex versus the syntax that John hates), someone would have to write a converter program, if you wanted to then import into the other wiki program.

Chris wrote:

… which as I read it confirms my hunch that choosing Instiki over WikiMedia increases the likelihood of unforeseen problems.

Dunno how you came to that conclusion, based on what I wrote, but whatever …

Jacques, how easy would it be for you to create a competing test wiki running Instiki?

Setting up an Instiki wiki under Linux or MacOSX is, by design, quite trivial. John intends to set one up on his RedHat machine. I’ll be happy to help him in the unlikely event that he runs into difficulties.

As I told Urs long ago, I don’t intend getting into the Wiki-hosting business here on golem. I already have enough services running on this machine. So, unless someone wants to spring for a newer, faster one, golem is going to stay out of the wiki-hosting business.

That’s why I wanted something that would be easy for people to set up.

Posted by: Jacques Distler on September 19, 2007 8:24 PM | Permalink | PGP Sig | Reply to this

### Windows

Setting up an Instiki wiki under Linux or MacOSX is, by design, quite trivial.

Speaking of which, I have never set up Instiki on a Windows machine. Which is why the Windows installation instructions are all-but-nonexistent.

So, if anyone has the inclination to set it up on their laptop, please take the time to fill in the instructions for doing so.

Others will thank you.

Posted by: Jacques Distler on September 19, 2007 9:45 PM | Permalink | PGP Sig | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Jacques Distler wrote:

Texvc has a whole slew of additional prerequisites that may not even be available (I don’t know) on the webhost Blake chose for the EUREKA wiki.

I managed to get math support working on EUREKA, so we can use the same server if we want.

In Instiki, exporting the the complete wiki in source-form is a trivial operation. Two mouseclicks gives you a tarball of Markdown files. I don’t know how to export an entire wiki, in source form, from MediaWiki. Maybe Chris can inform us.

This page has some information on exporting MediaWiki pages, either with the revision history or without. The existing export tools produce XML content, which may introduce an added complication to the converter program: it’ll have to parse the XML before running regular expressions (or whatever) to change the markup syntax.

Posted by: Blake Stacey on September 19, 2007 10:12 PM | Permalink | Reply to this

### Exports

This page has some information on exporting MediaWiki pages, either with the revision history or without.

Not exactly user-friendly. But, at least it’s possible.

The existing export tools produce XML content, which may introduce an added complication to the converter program: it’ll have to parse the XML before running regular expressions (or whatever) to change the markup syntax.

I’m sure that will be oh-so-much fun to write. Glad I don’t have to do it.

Posted by: Jacques Distler on September 19, 2007 10:35 PM | Permalink | PGP Sig | Reply to this

### Dump

To make things slightly easier for anyone contemplating writing such a converter. I added the ability to dump the Instiki database to YAML and, conversely, to load an Instiki database from YAML.

My reason for doing this had nothing to do with writing such a converter. It was based on the desire to make migrating databases as smooth and easy as possible.

But, since there are plenty of tools available (e.g. YAML and XML::Simple in Perl), converting between Instiki’s YAML dump and MediaWiki’s XML dump formats should be easy.

Converting between Markdown+itex and MediaWiki+texvc markup is left as an exercise for the masochists among you.

Posted by: Jacques Distler on September 20, 2007 11:29 PM | Permalink | PGP Sig | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Yes, MathML would rule out any effective participation by me. But I can see that automatic Latex conversion might be weighted much more heavily by Urs!

One important issue which Jacques hasn’t yet addressed is how the alternative platforms compare in terms of stability. One possible drawback of Instiki is that it is still under development, whereas MediaWiki is fairly well developed (albeit with some important limitations which we have already discussed).

Posted by: Chris Hillman on September 18, 2007 11:14 PM | Permalink | Reply to this

### Stability

One important issue which Jacques hasn’t yet addressed is how the alternative platforms compare in terms of stability. One possible drawback of Instiki is that it is still under development, whereas MediaWiki is fairly well developed (albeit with some important limitations which we have already discussed).

Under development ≠ unstable. (For what it’s worth, MediaWiki is also under fairly active development.)

Scalability is certainly an issue.

The default WebServer (WEBrick) and the default Database Engine (SQLite) are not designed with high performance in mind. I don’t think they would perform well with hundreds (let alone thousands) of simultaneous users.

One can, fairly easily, migrate to a higher performance WebServer (Apache+Mongrel or Apache+FastCGI, say) and a higher performance Database Engine (MySQL, say), if this became an issue.

But, somehow, I don’t think your Wiki is about to become the next Twitter (another Ruby-on-Rails application that, at 11,000 requests/second, faced some serious scaling issues ).

One nice thing I will say about SQLite is that it’s dirt-simple to backup. The database is a ordinary file. Copy the db/production.db.sqlite3 onto a pen drive, and you can slip all the data in your Wiki into your shirt-pocket.

Posted by: Jacques Distler on September 19, 2007 3:56 AM | Permalink | PGP Sig | Reply to this

### Re: Stability

I wrote:

Scalability is certainly an issue.

I suppose, to be pedantic about these things, I should distinguish between performance (on given hardware, how many simultaneous users or request/second or whatever can it handle?) and scalability (if you’re willing to throw more/better hardware at it, how much can you improve those numbers?).

As the denouement of the Twitter story, that I linked to above, shows, Rails can scale pretty well. But there’s no denying that Ruby and Ruby-on-Rails are pretty slow, compared to PHP.

I don’t think that performance or scalability are really going to be an issue, with the expected number of users of this Wiki.

And the performance “penalty” is far-outweighed by the benefits of better-written, more easily extended and modified, code.

I looked at several different Wiki software packages (including MediaWiki) before settling on Instiki as the one I wanted to build upon. There are good reasons that I made the choice that I did.

Even though it meant I’d have to teach myself Ruby…

P.S.: It appears that the long delay in posting comments was the result of an embarrassing misconfiguration. Apparently, you need to explicitly specify

LaunchBackgroundTasks true

in the configuration file. That didn’t used to be the case…

Posted by: Jacques Distler on September 19, 2007 8:01 AM | Permalink | PGP Sig | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Oh good, it seems that John is setting up a test Instiki installation of “The HyperDimensional Cafe” at UC Riverside and Blake is setting up a test MediaWiki installation of “Weekipedia” on the same server as Eureka? Please post the URLs when you have them! I think have these two sites to play with and compare will be very useful.

Question for the academics among you: any experience at your departments of using an internal wiki to document your system?

Posted by: Chris Hillman on September 24, 2007 5:57 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Chris wrote:

… it seems that John is setting up a test Instiki installation…

The present progressive is inaccurate here. I plan to attempt this when conditions are suitable.

Among other things, I’m waiting for Blake to tell me it’s time for the EUREKA publicity blitz. This will involve doing some guest interviews and the like.

Whatcha say, Blake? Does EUREKA seem ready — ready as it’s gonna get anytime soon, that is?

I think having these two sites to play with and compare will be very useful.

Yes… but maybe you’ll like one, and I’ll like the other.

I guess that’s no disaster. The main thing is that everyone have a place they like to work. But, it’s a bit too bad that you continue to rule out anything involving MathML, while never explaining why you don’t (or can’t) download the necessary fonts.

Speaking of which: I thought of a nice name for a math wiki of the sort Urs is imagining: The Wizards’ Workshop. Note the plural on ‘wizards’.

Question for the academics among you: any experience at your departments of using an internal wiki to document your system?

Not exactly! Our university uses the Blackboard Academic Suite.

Posted by: John Baez on September 24, 2007 6:36 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

I thought of a nice name for a math wiki of the sort Urs is imagining: The Wizards’ Workshop.

I like that! “Workshop” is cool. “Wizards’” is fun.

On a second thought, I already see myself running into lots of strange looks as I refer people to the “Wizards’s workshop”, with the title insinuating that it contains unseen magic and with the reassurance that it’s $n$-categorical this may not help open certain doors.

On a third thought, it may help open other doors. Who knows.

But I’ll want a logo which depicts a wizard who has just conjured up a pentagon 2-cell or alike in front of himself.

Posted by: Urs Schreiber on September 24, 2007 10:36 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Indeed, ‘Wizards’ Workshop’ is probably too flamboyant and goofy to gain the respect of elder mathematicians — it’s better for attracting young ones.

Maybe there’s a way to tone it down while keeping some of the same aura.

$n$-Category Workshop’? That at least goes along nicely with ‘$n$-Category Café’. In front, we have a café where people can sit around and talk. In back, we have a workshop full of tools, where people can work.

Unfortunately, a ‘workshop’ also means a small conference. This is unlikely to cause confusion if we say ‘The Wizards’ Workshop’, but it could easily cause confusion if we talk about an ‘$n$-Category Workshop’.

$n$-Category Workroom’?

‘Mathematical Workshop’?

Posted by: John Baez on September 25, 2007 5:42 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

$n$-Category Blackboard?

$n$-Category Laboratory?

$n$-Category Kitchen? (the place where you make the stuff that’s consumed in the Café)

Posted by: Simon Willerton on September 25, 2007 5:59 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

$n$-Category Blackboard?

$n$-Category Laboratory?

$n$-Category Kitchen? (the place where you make the stuff that’s consumed in the Café)

I like all of these. But I think we might want to have blackboards, laboratories and kitchens inside the workshop, and also have a room that contains a showroom, or exhibition, where we present the things that have been cooked up, reworked, then polished. Also a museum, and an exhibition hall.

Posted by: Urs Schreiber on September 25, 2007 6:19 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

The $n$-Category Wiké? (sorry)
Posted by: Allan E on September 25, 2007 6:54 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

John: to be perfectly brutal, the younger ones are the only ones who matter :-/

Blake: when you said “our official policies”, you meant “at Eureka Journal Watch”, correct? Any timeline on “Weekipedia”?

Posted by: Chris Hillman on September 26, 2007 10:22 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

John Baez said,

Among other things, I’m waiting for Blake to tell me it’s time for the EUREKA publicity blitz. This will involve doing some guest interviews and the like.

The only thing I’m not particularly happy about is the fact that we have Journal Infoboxes on the physics journals but not the math ones. There’s no intrinsic obstacle to fixing this; it just requires time to do script-work for combining the AMS information with Bruce Bartlett’s info template — time I haven’t had this past week.

Posted by: Blake Stacey on September 25, 2007 5:42 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

After a moment’s reflection, I realized that I had also wanted to start a discussion about our official policies. We should have some sort of “Statement of Principles” established before we start a gung-ho advertising campaign. This Statement could also include a succinct explanation of our replacement for Wikipedia’s NPOV policy. (We’re basically chucking their No Original Research requirement out the window, inviting people to share their personal experiences with journals and publishers, but I think we should have some guideline in place about how such information should be attributed.) Finally, we should put forth a few bullet points about user conduct: what do we expect from people who sign up, and what do you have to do to get booted from EUREKA?

Posted by: Blake Stacey on September 25, 2007 5:57 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Okay. No rush, no pressure. If you think you’ll have time to do this in a few weeks, I’m very happy to wait. If you think it’ll be a few months or millennia, I’ll go ahead with what we’ve got now.

Posted by: John Baez on September 25, 2007 9:42 PM | Permalink | Reply to this
Read the post On String- and Chern-Simons n-Transport
Weblog: The n-Category Café
Excerpt: Slides on String- and Chern-Simons n-Transport.
Tracked: October 23, 2007 9:49 PM
Weblog: The n-Category Café
Excerpt: A survey and comparison of the various notions of generalized smooth spaces, by Andrew Stacey.
Tracked: January 3, 2008 11:01 PM

### Re: Toward a Higher-Dimensional Wiki

This may not fulfil your needs, but it might go part of the way, and it’s available now. There’s a site “Wikibooks” which is a collection of online, world-editable textbooks. Some of them are only topic outlines with no contents; some of them are complete books the author has donated; some of them are being written there. They might very well welcome a new one on n-categories – or quantum mechanics – constructive logics – or toposes – just what would it be called, anyway?

I find categories and related matters fascinating – I return to them time and again. My big problem is that it all seems easy. Simple ideas get piled onto simple ideas until the pile is high enough that it falls over, so to speak, and I’m suddenly lost. That’s why I wanted to write these notes – it might help me hold it together long enough to see where it’s going.

I’ve been thinking of starting a blog as I try to figure out these things - or maybe a wiki – it would be a “what I’ve managed to figure out” kind of site, which would migrate from being tentative notes and hopes to something more definitive. So far I’ve been wondering just what kind of software to run the site.

I currently have a site available that runs pmwiki. Pmwiki’s recipes for math appear to be things called ASCIIMath and JsMath. Does anyone have the kind of experience that might tell me which of these would work better?

And Thanks to John Baez for the n-category trail. It points the way without getting bogged down in details. It’s inspiring. But I’m afraid understanding won’t come without the details. The details are the kind of thing I’d be trying to work out.

Posted by: Hendrik Boom on April 23, 2008 6:00 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Google released today a new service: Knol.

It is a kind of wiki, but it has certain resources. I guess it will suit the needs that people here were searching for.

“Experts in a given subject log into a Google account and use the Knol software to post an item, also known as a knol. In some senses, the process is like producing a blog post - but in this case it’s not something written off the cuff but carefully crafted to coherently explain a single subject.

One key attribute: Knols are meant to be signed with the author’s actual name. With permission, Google will actually verify the writer’s identity, either by credit card or phone.

“Knols are treated pretty much like any web page”

“There’s no limit on how many people can write knols on the same subjects”

wired

And this is the service

Posted by: Daniel de França MTd2 on July 24, 2008 1:26 AM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

How’s progress on nLab going? We wouldn’t want to be left behind by the other culture.

Posted by: David Corfield on October 16, 2008 1:14 PM | Permalink | Reply to this

### Re: Toward a Higher-Dimensional Wiki

Looks like a very old version that wasn’t installed correctly. (Note that none of the math shows up.)

Posted by: Jacques Distler on October 16, 2008 4:04 PM | Permalink | PGP Sig | Reply to this

### Re: Toward a Higher-Dimensional Wiki

I hereby give up on trying to get Instiki working at UCR. I can’t do this sort of stuff myself without learning a lot and getting permission to write in certain directories. I don’t have time for that. So, I relied on our computer guy to do it. I guess he didn’t do it right.

So, if anyone else wants to set up a $n$-category Wiki, please go ahead and give it a try. I would like one to exist.

Posted by: John Baez on October 16, 2008 6:27 PM | Permalink | Reply to this

### Theorems

Technology marches on.

Any decent mathematical Wiki should have built-in support for things like Theorems, Proofs, etc.

This past week, I added support for Theorem-like environments to Instiki.

There’s built-in support for

 theorem     (for Theorem)
lemma       (for Lemma)
prop        (for Proposition)
cor         (for Corollary)
defn        (for Definition)
example     (for Example)
remark      (for Remark)
note        (for Note)


but it’s relatively trivial to add new environments (without mucking about with the Instiki source code!).

And the LaTeX export is amsthm-compatible.

The next frontier (at least as I see it) is integrating some bibliography management features into Instiki. Interfacing with Zotero seems like a promising route to follow.

Posted by: Jacques Distler on October 20, 2008 2:22 PM | Permalink | PGP Sig | Reply to this
Read the post Beyond the Blog
Weblog: The n-Category Café
Excerpt: How to make best use of blog material.
Tracked: November 25, 2008 2:08 PM