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»

Since I wrote this, I thought someone might find it useful, so I share it with you:

Notes from a talk I gave in a student's seminar in Freiburg:
Komplexe K-Theorie: Bott-Periodizitaet (complex K-Theory: Bott periodicity)

It's almost the same proof as in Aityah's nice book, but maybe a little bit more lengthy (and in german).

... right now I'm sitting in the library at the ICTP in Miramare/Trieste, Italy. It's a beautiful place, and I think I'll write something about the summer school on Hodge Theory here, soon!

Hi, I was reading in

Jet Nestruev: Smooth Manifolds and Observables, Springer, 2003

about a month ago (after I stumbled over a question on MO) and there was an exercise that resisted solution for more than a week.

Well.... now I found out that I have just misread the exercise. However, this way I basically did several exercises at once. Here comes the problem and its solution:

The problem

(inspired by page 28, chapter 3, exercise 3.17.5 in Nestruev)

Find a smooth (real) manifold $M$ such that its algebra of smooth functions $C^\infty(M,\mathbb R)$ is isomorphic to the algebra of all smooth functions $f : \mathbb R \to \mathbb R$ that have some rational period $\tau$ (i.e. there exists $\tau \in \mathbb Q$ such that $f(x)=f(x+\tau)$ for all x). Note that we don't fix a period $\tau$ here. Let's call the algebra in question (smooth functions on the real line with some rational period) $A$.

You might want to stop reading here and think for a second (or minutes) about the solution or similar problems that have easier solutions. A more vague problem would be

Find a space $M$ such that the functions $M \to \mathbb R$ correspond to functions $\mathbb R \to \mathbb R$ that are periodic with some rational period.

Continue reading «A manifold whose functions are the smooth functions on the real line with rational period»

MathOverflow is a relatively new place for mathematicians to ask and answer research questions or just watch other mathematicians' discussions to learn. Since it's growing like the arXiv, it's no longer possible for me to read everything interesting without investing "too much" time. Like for the arXiv, where we have the arXiv Blog that looks for some of the most interesting (physics) papers submitted, there ought to be an excerpt-of-MO, too. This way, you could subscribe to your special fields of interest in a feed reader and additionally read some not-that-specialised questions picked by someone else.

I'm not going to do this, but in this post I'll present some of my favourites from the last months at MathOverflow (omitting the more subject-specific ones):
Continue reading «Found on MathOverflow»

We look at the model structure Voevodsky and Morel use in their 1999 IHES paper and discuss 1.2, 1.3, 1.4, 1.5, 1.6, 1.8, 1.9, 1.10. There is nothing difficult or particularly interesting, but you might want to look up some specific issue or reference.
Continue reading «Walk-through to Morel-Voevodsky A¹-homotopy theory, page 48-50»

On dimensions-math.org you can see a whole bunch of before unseen geometry videos introducing 2-, 3- and 4-dimensional space, complex numbers and even more to the non-mathematician (somewhat similar to the well-known Not-Knot-videos and the Moebius transformations on YouTube, but with lots of explanations). The computer animations are available on DVD and online, for free. The explanations are in many different languages.

This is something not to miss if you're interested in mathematics, and it might also be valuable if you're taking a first course in complex analysis. Even after you've taken a course on complex analysis, you might enjoy the animation of the Hopf fibration (which I liked most).

Go straight to watching the videos in English.

via The Math Less Traveled (via Wadler's Blog)