I guess you all know what a WikiWikiWeb (short: wiki) is, it's a website where you can easily add new pages and modify existing ones. MathOverflow is some kind of hybrid between Q&A and a wiki, since users with enough reputation can edit other people's questions and answers. MathOverflow made the Markdown syntax very popular, and people got used to using LaTeX online. Some of my readers surely know the nLab, a collaborative wiki on n-categorical math(ematical physics) and stuff. The nLab runs on a software called Instiki, which is a wiki written in Ruby (an intepreted language similar to Python, and somewhat similar to Lisp, Perl and JavaScript; which is often used for web applications like wikis). The good thing about Instiki is that it supports editing pages in Markdown syntax with embedded LaTeX, so it is able to support your personal knowledge management needs. In addition, Instiki is small (thus not many bugs are to be expected), fast and the code is quite readable; something I wouldn't say about MediaWiki, the software behind Wikipedia.

In this post, I will tell you how to run your own wiki like the nLab. [UPDATED 2013-01-07; easier fix]

Continue reading «Get your own LaTeX-enabled wiki in the cloud with Instiki on Heroku»

The new term has begun! And with it a new academic year in Freiburg.

In the past I used to put extensive notes online, for any talks I gave (mostly in local seminars at my university). I have changed this to posting blog posts instead, but sometimes I also have some teXed talk notes. The quality of the teXed notes is usually bad, as I didn't intend to publish them. This is a compilation of talk notes from the last academic year.

Goal for the next year: focus :-)

• Seminar on Systolic Geometry: Aspherical Manifolds and Essential Manifolds.
• Seminar on Perverse Sheaves: Introduction to 6 functor formalism. I also blogged some stuff even more elementary about 4 functors before.
• Seminar on Geometric Langlands: From Langlands for Function Fields to Geometric Langlands; I have blogged an introduction and also some of the talk on Geometric Langlands here.
• Seminar on Cobordism: Bordism, Cobordism and Spectra (there's a blog post). There are also slides on the cobordism spectrum, though I remember it was definitely on a blackboard.
• Seminar on Mapping Class Groups: Spectra and Infinite Loop Spaces (these notes are actually not that bad).
• Seminar on Galois Representations: Grothendieck's Monodromy Theorem. I have written a small note on supernatural numbers, which appear in Tate's proof. There are also (bad, uncorrected) talk notes on Weil-Deligne representations in german.
• Seminar on Multiple Zeta Values: Upper bounds on periods (link goes to full lecture notes, which are quite good now).
• Student's conference of the german math society: 20 minutes on A¹-fundamental groups of isotropic groups.

If you manage your (scientific) references, such as journal articles, arXiv papers and textbooks within some reference management system that uses BibTex as storage/export format, and you have local copies of your files, then the following might be of interest:

I wrote a JabRef export filter that takes a BibTex file with file links (so, BibTex fields of the form file={somefile.pdf}) and writes a linux shell script to rename the files systematically according to the scheme [bibtexkey] - [authors] - [title].[extension]. Then JabRef can find the file again via its automatic file association mechanism. I use lower-case bibtexkeys but the export filter is easily adaptable, read about it on the JabRef custom export filter documentation page.

Just create (or download) a file named "renamer.layout" and fill in this line:
\begin{file}mv "\format[FileLink]{\file}" "\format[ToLowerCase,FormatChars]{\bibtexkey} - \format[AuthorNatBib,ToLowerCase,FormatChars,RemoveBrackets]{\author} - \format[FormatChars,RemoveBrackets,ToLowerCase]{\title}.\format[Replace(.*:,),ToLowerCase]{\file}"\end{file}
then open JabRef and go to the menu entry Options->Manage custom exports->Add new where you enter (for example) "renamer" as Export name, the full path to your renamer.layout file in the Main layout file field and "sh" as File extension.

Then open your BibTex file (.bib) with JabRef and then select the menu entry File->Export and select in the drop-down-menu Files of Type your newly created export filter renamer (*.sh). This gives you a shell script which, if executed, renames all files linked from the BibTex document into a standardised format (and moves all into the directory from where you execute the script).

Continue reading «Mass renaming papers with BibTex+JabRef export filters»

A long time ago, I switched from Micro$oft Windows to GNU/Linux. Since Ubuntu, I even recommend GNU/Linux to non-computerfreaks. Sadly, Ubuntu is not perfect. In particular, some applications are still missing. What follows is a wish-list of future Ubuntu features/applications. Some of these are available on Windows or Mac OSX, most aren't.
Continue reading «A survey of GNU/Linux shortcomings»

When I woke up from a dream, I instantly had this idea: What would a file format for odours look like?

I admit: this is one of the most absurd posts ever...

On searching "smell file format", the results are really absurd, too.
Continue reading «the smell file format»

Today in the series "How to do XYZ with software?":

Annotations and other metadata issues

(You might not want to read this if you're not using Linux or if you're not a developer)
Continue reading «Managing the paper's metadata»