Tag Archives: Internet

Pretty Math on Wikipedia

In the days of MathJax, the math images on Wikipedia look inferior by a huge margin. The MathJax guys got us covered; they provide a userscript1 that dynamically injects MathJax into Wikipedia sites2. It may load a little longer, but I think this is worth the wait:

Wikipedia Math Vanilla

Without MathJax

Wikipedia Math Mathjax

With MathJax


  1. Userscripts are pieces of Javascript your browser executes on top of any website. Firefox users use Greasemonkey, others see here.
  2. Make sure to change the @include to http://*.wikipedia.org/wiki/* so the script works on all Wikipedias.

Computer Science Stack Exchange Live!

Computer Science Stack Exchange public beta

cs.SE in nondescript beta style

Since my post in December, Computer Science Stack Exchange has gone through private beta and is now accessible for everybody. Head over to cs.stackexchange.com and take a look! We are waiting for your questions so do not hesitate to post anything you have always wanted to know in computer science1, be it theory, applied or even practical!

We also need more expertise: out off almost 190 questions sixteen have yet to receive a good answer. among those are one about equivalence of Büchi automata and linear μ-calculus and another about efficiently learning regular languages.

You might also want to check out our hottest questions, including why Quicksort is often considered the best sorting algorithm, encryption using NP-hard problems and connections between Gödel’s incompleteness theorem and the halting problem.

I am very excited about this site. One one hand, it gives me the opportunity to share my knowledge in computer science with a wide variety of people, and I like teaching. On the other hand, I get to learn a lot. Not only do people ask about things I know next to nothing about so I can learn from the answers, but there are also original concepts. My favorite is Patrick’s proposal of heap automata; I have spent several hours contemplating his question about their power and follow-up questions.

I hope to see you on cs.SE soon!


  1. Mind the FAQ, though.

Better Default Search in Browsers

A typical search result on duckduckgo.com

A typical search result

Several weeks ago, certain channels announced that Linux Mint changed their default search engine in Firefox to DuckDuckGo. I do not care much for Linux Mint but decided give DuckDuckGo a try.

What is the matter, you might ask? I used to use ubiquitous Google for everything related to web searches (if nothing else). Whenever I would search for something, I would type some keywords in Firefox’ address bar, hit enter and pick promising Google results. For instance, instead of visiting Wikipedia by hand I would Google wiki Murphy's Law and hit the first link. Combined with bookmark completion, this worked so well that I almost never typed in a proper URL anymore.

The big issue is privacy. It is well-known that Google saves search results and tracks users for their own purposes and to set up their filter bubble1. Read more »


  1. While the bubble has its advantages I dislike the potential for censorship it offers.

Computer Science StackExchange Upcoming

A screenshot of the current proposal for a computer science site in the StackExchange network.

I have posted about Stackexchange before. Helpful folks on various sites have solved many a problem I have had since then. I have posted a bunch of answers which—hopefully—helped out others in return. To say the least, I am convinced of the StackExchange model and am continually amazed at its effectiveness.

The wealth of knowledge saved on the StackExchange network1 has become so extensive that if you google for programming or LaTeX related problem almost certainly a question on Stackoverflow or tex.SE comes up. If not, asking there is often faster than searching the webs and/or trying around. Especially on tex.SE you can expect great answers in a matter of hours.

Now an exciting thing has happened: A proposal for a computer science site has reached commitment phase! That means that a number of people have to vote for the site in order to move it to a beta phase after which it will be a full-fledged member of the network2. The new site is to complement Stackoverflow and its derivates on one and cstheory.SE on the other side, filling the massive gap in between. I am very excited about this; if the community on cs.SE can be only half as good as on some other sites we are about to create the best resource for computer science students, researchers and users the web has seen so far.

But we are not there yet! First we have to have enough people commit to using the new site, then we need a successful beta. If you want this to happen, head over to area51, commit and be part of the community from the start!


  1. Licensed under Creative Commons, mind!
  2. Find more information about the process here.

DRM or what?

You might have heard of Richard Stallman, if only from references in a well-known nerd webcomic as I did until lately. He has apparently been well known as passionated programmer from the old days, his efforts around GNU and his activities advocating free software. I found this talk of his by accident. It is from early 2009, so not new but still relevant. It is a great talk on many levels even if you do not agree with him on every statement. It is provocative and I guess deliberately so; it certainly got me thinking.

I agree on many points. DRM — nice wordplay of his here — is crap. When I was a kid, we borrowed books from friends, recorded music from radio on tapes and TV shows on VHS. This was perfectly legal as long as you did use the material only in private and not to make any profit. I had my first major cynical moment when, years ago, Sony and others pushed laws that prevented us from copying CDs and invented nasty copy protection that more often than not mad the disk not work but, at the the very same time, I found CD-Rs by Sony labelled as specifically suited for music. This perfectly represents the double morale at work there that cares only about profit. But then, this is what capitalism is about, right?

Stallman starts with a historical analysis, embedding the current situation in the development of copyright law over the last 2000 years. I find this analysis to the point; he clearly points out that the original aims of copyright are no longer achieved. The solutions he proposes make sense: give a copyright for up to ten years that ensures exclusive marketing rights but let sharing be legal. Especially sexy is his idea of a music player with a button that donates 1$ to the artist of the current song. Why has nobody implemented this yet?

His postulation of a big conspiracy is maybe a bit overstating. Sure, big companies form cartells to firm up their monopolies, that is a well known fact. But they do it openly, so you cannot call it a conspiracy. The fact that their behaviour is accepted by many is sad, tough. A friend of mine bought a proprietary DVD player software for her Linux PC, just to be safe.

Sony sells CD-R specifically for music on amazon

In general, Stallman argues on an ethical level, claiming that our personal freedem is eroded by DRM and copyright law. I cannot fully agree with that since I have not yet been forced to buy such products. If you reject any thusly protected good, though, you can not fully participate in our modern culture. This in itself is certainly a problem. I prefer, however, a more worldly approach: the argumentation of companies employing restrictive licenses or even DRM is just wrong. They claim that the number of (illegal) downloads times piece price equals their loss. This is not true, period. There is no telling that any downloader would have bought the piece. In fact, a number of people I now download music and buy the album afterwards if they like it. As Stallman points out, there are quite a number of examples were free sharing and donations got artists going. I seem to remember that the Arctic Monkeys took off that way. In any case, the flood of lawsuits demanding outrageous amounts of money from individuals has its very own negative impact on economy.

There is one part of Stallman’s talk where I strongly have to disagree, though. He demonizes publishers in general and basically advocates leaving them out entirely, focusing on the artist-customer relationship. This idea might look appealing from the ethical point of view but will never work. We need publishers, without them there can be no art or any product that lives up to the quality standards we have become used to. This might be less true for software and ebooks, but all the more so for printed books, musik and especially movies. Investments in editors, studios, remastering, case and CGI have to be covered and are expensive if executed by experts. Furthermore, think of translations and advertising in order to target the world market at all! Successful authors say that without publishers it would be very hard to be a full-time writer². Therefore publishers have their well-deserved place and they deserve to be paid for it appropriately.

In the end, we need laws and — more importantly — a public mindset that ensures that artists can live of their art if they are good and that publishers have a reason to invest in bringing the art to us. And, of course, that at the same time allow us to access art and other products of the mind (relatively) freely and without being criminalised. These are contradicting requirements, therefore we need a compromise. The current situation is clearly on the far side of freedom and might even though not take care of artists enough¹. Stallman, on the other hand, advocates something that is not compatible with capitalism at all. If we can meet in between, we will have achieved something good. But Stallman is right when he says that in order to overcome the power of rich companies we have to speak up loudly and claim our heartfelt rights in the same way as the companies stake their claims. In a functioning democracy politics take care of the compromise then. I hope.

1: Note that in Germany, copyright law works slightly differently than in the US and certainly for the better. The Urheberrecht can never be transferred from the artist to anybody else, so artists never lose control over their work.

2: Listen to this podcast.