## September 1, 2009

### nLab Migration Done

#### Posted by Urs Schreiber

Thanks to Andrew Stacey, it’s finally done: after a bit of testing the $n$Lab has finally successfully migrated to a new server.

That means:

- as far as you go about accessing and using it nothing in the usage has changed: in particular you still access the lab at http://ncatlab.org/nlab

- but using the $n$Lab should be a better experience now: the server reaction is much quicker now, the whole thing should be stable now.

If you are interested in more technical discussion of what happened, see the $n$Forum. But of course, you don’t have to be interested in any behind-the-scenes technical discussion for using the $n$Lab.

Instead, you may want to be the one to create entry number 2000 by writing a piece on your favorite topic that is ignorantly ignored so far. The moment of this writing the nominal count of entries is 1965.

Viewed from one perspective this may look like a large number. But viewed from the right perspective it is a very small number. We are only just getting started, still. But it’s looking promising.

Posted at September 1, 2009 9:55 AM UTC

TrackBack URL for this Entry:   http://golem.ph.utexas.edu/cgi-bin/MT-3.0/dxy-tb.fcgi/2047

### Re: nLab Migration Done

We need more articles, but we also need better articles, with more theorems and better explanations.

Come on, everyone! Go to the nLab. Search for your favorite math topic. If it’s not there, add it. If it is there, add the most important theorem that’s missing from this page… or add a more intuitive explanation of something.

I’ve been busy finishing up too many papers to contribute a lot to the $n$Lab, but I had fun adding an entry on semicartesian monoidal categories, with a bunch of examples — and also a theorem about cartesian monoidal categories. These are tiny pieces of wisdom that are hard to find in books. We all have ‘em!

Posted by: John Baez on September 1, 2009 5:02 PM | Permalink | Reply to this

### Re: nLab Migration Done

By the way, in case anyone wants to try: Here is how to add definition/theorem/proof environments.

The syntax for that is not exactly wikiwiki, unfortunately, but one can just copy-and-paste the examples listed there. I always have this page open in the background to copy-and-paste from it.

Posted by: Urs Schreiber on September 1, 2009 7:08 PM | Permalink | Reply to this

### Re: nLab Migration Done

Search for your favorite math topic. If it’s not there, add it.

So long as it’s not neutrosophic rings.

Posted by: David Corfield on September 2, 2009 9:00 AM | Permalink | Reply to this

### Re: nLab Migration Done

This is something that we need to decide before we get large numbers of new contributors (or as soon as possible if that's too late): What is the scope of the $n$-Category Lab?

I've been taking it to be mathematics, physics, and philosophy related to $n$-categories. Neutrosophic rings are ruled out by virtue of not being mathematics (and not even pretending to be the others), but sometimes this will not be so clear. The original contributors, besides making honest mistakes, also write tentative material on new ideas, stuff that might turn out, in the end, to be as nonsensical as neutrosophic mathematics. While we're working on it, we hope not, but we don't know yet.

Wikipedia keeps out the cranks with the rule of no original research. But that rule won't work on the Lab, which is a place to work, not simply a place to report and summarise; we're working in a lab, not working on an encyclopædia. So how to we decide what original research to allow, knowing that cranks will someday come along and try to add theirs?

I am writing some more detailed ideas on the Forum, since I would like people to reply and get into discussing this matter, and this thread is not the right place for it. When I've finished that, I'll link it in a follow-up comment.

Posted by: Toby Bartels on September 2, 2009 4:58 PM | Permalink | Reply to this

### Re: nLab Migration Done

I am writing some more detailed ideas on the Forum, since I would like people to reply and get into discussing this matter, and this thread is not the right place for it. When I’ve finished that, I'll link it in a follow-up comment.

Posted by: Toby Bartels on September 2, 2009 5:37 PM | Permalink | Reply to this

### Re: nLab Migration Done

Our esteemed hosts have upgraded the memory on the nLab. My intention was to post a warning here, but they did it faster than I was expecting! So there’s almost nothing to say here except that in the process of upgrading, we had to get a new IP address (details are too complicated to bother with here). This change needs to propagate through the internet and, depending on your internet connection, may take a short time to reach you. It didn’t seem to take too long last time, but if you find that you get something funny then this may be the reason why.

If you’re on a unix machine then you can test if you’re in the New Reality or not by typing:

# host ncatlab.org


If the answer has the numbers 68.233.9.66 then welcome to the New World. If 74.63.3.116 then please be patient, your version of reality will soon match the true one.

Posted by: Andrew Stacey on September 3, 2009 1:29 PM | Permalink | Reply to this

### 2000

According to Andrew Stacey, entry number 2000 goes to Zoran Škoda with smooth morphism of schemes.

Zoran has done a whole lot of work on the $n$Lab, especially on algebro-geometric entries. We should create a “topic cluster” for that eventually.

Then we are ready to seriously attack derived algebraic geometry, $n$Lab-wise. I’d like to do that in the slightly more general context that deserves to be called higher geometry. In fact notions such as structured $(\infty,1)$-topos are way more general than the generalized schemes considered in derived algebraic geometry, it would seem.

Posted by: Urs Schreiber on September 7, 2009 1:31 PM | Permalink | Reply to this

### Re: 2000

Turns out there was some miscounting going on:

Entry number 2000 on the $n$Lab is instead the one on Grothendieck connection.

But that is also by Zoran! :-)

And this is a great entry to use for celebration. I have added a “revisionist” “Idea” section to it to amplify the important conceptual idea beneath the technical stuff.

Posted by: Urs Schreiber on September 7, 2009 5:49 PM | Permalink | Reply to this

### Re: 2000

Yeah, okay. I was just counting pages in the database, which includes all the webs. So what I put on the latest changes should be read as referring to the whole system rather than just the nLab.

Posted by: Andrew Stacey on September 8, 2009 3:40 PM | Permalink | Reply to this

### Re: 2000

Yeah, okay. I was just counting pages in the database, which includes all the webs. So what I put on the latest changes should be read as referring to the whole system rather than just the nLab.

No worries, Andrew. It doesn’t really matter much. This counting game was just for fun.

Then next fun goal to aim at is a nominal number of 100 authors. Currently we are at 94.

I trust that Scott Carnahan is about to add this sentence, which will make it 95. ;-)

Posted by: Urs Schreiber on September 8, 2009 4:12 PM | Permalink | Reply to this

### Re: 2000

You get the nominal number of authors by counting the list here (assuming that every nominal author that has edited at least one web has edited the main web, which I think is true now). You get a more realistic number of authors by counting the list here (assuming that it's up to date, which is true now). The actual number of authors will be a bit larger than the latter, due to Anonymous Cowards.

Posted by: Toby Bartels on September 8, 2009 7:46 PM | Permalink | Reply to this

### More Migration: Latest Changes

Not having posting rights on this blog, I’m putting this here in the hope that those following developments on the n-lab will see it.

We are proposing shifting the place for recording latest changes to the n-Forum. This will provide the following advantages:

1. It will be better organised and so easier to see new items, and replies to existing items.
2. There is an RSS feed so you can follow developments without having to check this page every 5 minutes (you know who you are).
3. Updates can be made simultaneously so you don’t have to wait for the person currently editing ‘latest changes’ to finish.
4. If you create an account on the forum (this is not mandatory), it will keep track of the items that you have read and inform you of new things.
5. It will be easier for you to find out about other possible changes to the infrastructure of the n-lab, and so have some influence on what makes this place run.

The system will be no more complicated than the current one:

1. Make your changes in the n-lab.
2. Click on the ‘latest changes’ link in the contents sidebar of the homepage (we’ll include a link (not a redirect) from this page for those who’ve bookmarked this one).
3. Click on the ‘start a new discussion’ in the panel (left hand side) of the page on the forum.
4. Fill in the details of the change. I suggest that the title of the discussion makes it clear which pages on the n-lab are referred to.
5. If you have an account, you will be invited to log in (if you are not already logged in). If not, there is a reCaptcha to solve to prove that you are human (or elven). If you do post “anonymously”, may we ask that you put your name at the top of your comment so that we know who you are.

You can subscribe to RSS or ATOM feeds from the forum. This will keep you up to date in your preferred ‘feed reader’ of what’s going on.

The syntax on the forum is ever-so-slightly different to that here. You can use markdown syntax, but it’s not extended markdown. Wikilinks work just as they do here (and point to the correct pages here). Mathematics is, currently, enabled via a Wordpress-style system where it gets converted to pictures. Enclose your mathematics within double dollars to get it to work. (Hopefully, this will change to a MathML system in the near future).

To have a look at the system, go to this page. When we “go live” (which will happen soon), I’ll clean out the discussions so feel free to have a play first. Any comments and suggestions should be recorded here (you’ll have to create an account to comment on this, though).

Posted by: Andrew Stacey on September 17, 2009 8:07 AM | Permalink | Reply to this

### Re: More Migration: Latest Changes

Once again, many thanks, Andrew. It’s really impressive what you are achieving here.

One quick comment on this:

Not having posting rights on this blog, I’m putting this here in the hope that those following developments on the n-lab will see it.

I’ll repost this as a guest entry later today, when I have a spare minute. Would have offered to do that yesterday, but didn’t find the time.

Posted by: Urs Schreiber on September 17, 2009 8:23 AM | Permalink | Reply to this

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