1. Easy video recording – let the user take videos with every webcam within seconds, then upload to YouTube or similar. A similar proposal (a simple video editor) is on the lifehacker.com five feature request list.
2. Stream capturing – saving streamed video data doesn’t work so easily with all those different streaming formats. For some, you need a RTSP stream catcher, then maybe a RTMP stream catcher and for some you seem to be able to use just mplayer. And then there are many cases where all fails. Technically, what can be played can also be saved. But then there is the big Flash Player obstacle – some Flash videos are well-protected. Gnash may help there.
3. PDF reader&editor – one tool that allows for reading PDFs, annotating them, publishing&sharing the comments, manipulating the PDF itself, adding additional layers, manipulating PDF metadata, etc. Just like the Adobe Acrobat Reader in its more expensive variant – but as open source tool with the ability to write plug-ins and integration into Gnome or KDE (or any) desktop. Okular is already on the right track! See also my article about editing PDF metadata.
4. Centralised instant messenger and (video)telephony – unite Pidgin, Skype and other Videochat and IM apps in one UI. Maybe put this together with microblogging tools, since people use their IM status messages like microblogging anyway. Skype has announced to open-source parts of their Linux client, so this is not totally out of reach. Open source alternatives to TweetDeck are also there, for example Gwibber. See also my article on microblogging and news.
5. Metadata in file browser – make the file explorer a metadata editor, paving the road for a semantic desktop. Even the Windows Explorer can do better than Nautilus for now! But then I haven’t tried KDE’s Dolphin for a while and this might be the right thing to do… See also my article on music metadata as well as my article on photo metadata.
6. Asset manager – even one step further, make the file browser a pluggable asset manager, that can take the shape of a photo collection manager, a scientific paper organiser or a website bookmark manager. So far I know only of commercial asset managers and haven’t yet investigated which one runs on Linux and might be useful for me. Do you have any recommendations?
7. Annotation everywhere – a note-taking application that can annotate every single file or item on the desktop. This way you can relate a specific email to a task, to a note, to a website, to an application and a specific file – thus documenting entire work-flow states for later continuation. Well, there is Tomboy for now. See also my article on note-taking.
8. Private browsing – create for Firefox or any other browser a CSS/Javascript security model that avoids CSS privacy hacks by not letting any information about how the HTML rendered leak into the Web. That would include creating an open source Flash plug-in that doesn’t publish all Font and SuperCookie information. See EFF’s PanoptiClick for more information about this. The SuperCookie issues can be softened with the BetterPrivacy Add-On for Firefox.
9. Easy emulation – integrate a Dalvik VM naturally into the desktop, so that it’s very easy to install&run Android apps from the applications menu. Maybe the project to implement a Dalvik VM in Java is the right way to do this. Of course, the same would be nice for Wine but I don’t consider this an option because Dalvik is open and Windows isn’t.
10. Synchronise data with external sources – I want to backup all configuration and some data files with a variety of places: external hard-disks and remote storage services in the Web (encryption is necessary here). Ubuntu One is already a big step forward but I really want to backup all configuration so I could crash my computer, buy a new one, hit the “reinstall the software that was there before” button and then everything is back to normal. This is (almost) technically possible. Another road is, that I want to backup the data stored elsewhere (Delicious bookmarks, Google Reader Shared news, Facebook comments, etc.) to my home computer so I’m not stuck with one provider forever (so I can quit Facebook some day). This seems to be impossible for now, but the problem lies in coding “adapters” that take data from one service and move it to the other one.

Am I the only one who wants these features? Are they that hard to implement? (Yes) Hey, for most of these features, I would pay some money (depending on how well it’s implemented). Oh well, and I admit that these features are not really Linux-related. It’s just that I use Ubuntu and would want to have solutions available on open platforms. I guess web-apps and Java- or .NET-based apps would be OK for me, too – but then look again at the wish-list and you’ll see that most features require desktop applications.

If you have suggestions for applications that solve one of those problems at least somehow a little bit, please leave a comment.

What is your favourite not-yet-there Desktop/Ubuntu/GNU/Linux feature?

The penguin image (Tux) is licensed from linux.org under a CC-BY-SA license

Searching for a mysterious “asdf jkl” bug is really difficult. I found about 3 different laptop keyboard problems similar to this one, although they always had problems with the “Enter” key, too. My “Enter” key worked fine. Even if those problems would have been more similar to mine, it wouldn’t have helped. Nobody who has had those strange keyboard issues has found a solution so far. First I looked for Ubuntu/Linux related problems, and looked through various log files, then I found out the keys didn’t work even on the BIOS level. Oh, it was horrible.

Then I found a solution.

The keys were dirty. Not like the yellow patina that you can see on old keyboards – I clean my keyboard regularly, so this doesn’t happen. Dust stuck deep inside, almost invisible. If it would be visible, I wouldn’t have looked for a software problem for an hour… I suppose the dust got wet from humidity in the air (sometimes I use my laptop in the kitchen).

How to repair a Lenovo Thinkpad T60 laptop keyboard that has some kind of strange some-keys-no-longer-working issue:

Turn off the computer and remove one key with your bare hands (gently). It’s most easy to begin with “g”, “h” or “b” because you can pull off the TrackPoint (the red mouse thing) first. Then you can remove all letters (or even more, at least remove the letters that don’t work).

Don’t forget your keyboard layout. It won’t be so easy to google the correct layout if you can’t type!

This is the place where you can find hidden dust. Removing this dust was crucial to get the keys working again (for me).

I wrote this, so that other Laptop users with the same problems can find the solution in google and don’t have to spend an hour of their life searching for non-existent bugs, like I did.

The words “cheese” and “wrap” are translated…

Let’s have a look at some of the best Web 1.0 math websites:

• The On-Line Encyclopedia of Integer Sequences – look up some short sequence of numbers to see in which patterns they fit.
• John Baez: This Week’s Finds in Mathematical Physics – John Baez has been writing his wonderful thoughts about mathematics, physics and the in-between for more years than I know what mathematics is. You can learn a lot from these notes. He has been posting it in sci.physics.research, sci.math.research, sci.physics and sci.math but now he also has an RSS feed, of course.
• The Mathematical Atlas – a hand-crafted tour through the various regions of mathematics, clustered along the AMS classification, spiced with many useful links. (I hope this will be relaunched as a community-based website one day. It deserves to survive).
• The Mathematics Genealogy Project – find out how half of all professors are descendants of Mersenne: 139335 mathematicians in the database, 61089 descendants of Mersenne. They have nice posters, too.

And now, before I sketch my vision of Math 2.0, for some of the best Web 2.0 math projects:

• The n-category café – a group blog about higher algebraic structures (especially n-categories) and physics. There are almost always interesting discussions going on.
• The Catsters – two mathematicians explain category theory (thus the name Catsters) in short, understandable snippets made exclusively for YouTube. Have you ever felt the need to learn what Monads are? String diagrams? Maybe you would be happy if someone would explain you limits and colimits. The Catsters do it, and they do it for free.
• The Open Problem Garden – a collectively maintained list of open problems in mathematics, ranked in difficulty. It’s still in an early phase of it’s life-time and somehow concentrated on problems with a combinatorial flavour, especially graph theory. Maybe you could enter your favourite open problem there?
• Wolfram Alpha – a mathematical data search and browse engine. You can look up statistics, perform comparisons and calculations and visualise this data. Very nice!
• Complexity Zoo – a website that collects computational complexity classes, with lots of helpful explanations and fact around them. At the moment of writing, they count over 480 complexity classes!
• Rigorous Trivialities – a group blog about algebraic geometry, with a huge series about “Algebraic Geometry from the Beginning” – which I recommend for it’s little intuitive text-snippets, where you can pick just what you need.
• The Secret Blogging Seminar – a group blog about algebraic geometry.
• The Unapologetic Mathematician – John Armstrong’s high-level educational math blog. You can pick some topic you want to learn and track back the links to the point where you’re on safe ground. This way, learning is much more efficient than using a linear book. Covers, for example, some category theory.
• What’s new – Terence Tao’s blog. He describes it with the words “Updates on my research and expository papers, discussion of open problems, and other maths-related topics”. Well said, worth a look!
• Timothy Gowers’s blog – currently obsessed with the PolyMath project (see below).

UPDATE: For a list less biased by my personal interests, see the thread “most helpful math resources on the web” on MathOverflow

Okay, now what is Math 2.0?

Math 2.0 is mathematics done collaboratively in genuine new ways over the internet.

This means, a website qualifies as Math 2.0 if it changed the way mathematicians collaborated.

However, it seems like the school education community, more focused on children, uses the term Math 2.0 as a buzzword for “learning math over the internet”.
From the Delicious tag Math2.0 you can see that the term is also used for math blogging.

Keep in mind that all this 1.0, 2.0 buzzword terminology is just tagging some websites. It’s not important, and as Tim Berners-Lee says, the web was always about communication from person to person, it’s nothing new.

My favourite Math 2.0 projects:

• The nLab – the wiki associated to the n-category café, an attempt to structure the discussions and facilitate re-use. This way, the nLab users build an expert encyclopaedia about their subject. Since it’s a subject with intense research going on, it’s more like their secret lab book than like the consensus-based Wikipedia. The rather inclusive viewpoint instead of the encyclopaedic exclusive viewpoint of Wikipedia has already created a very helpful collection of references. The nLab personal lab wikis have already shaped how people do their mathematical research, thus it truly qualifies for Math 2.0.
• MathOverflow – the mathematical question&answer web site, intended to be used by mathematicians (so, no homework questions on this site). Without MathOverflow you would have to know the right people. With MathOverflow you can just ask them.
• PolyMath – the first massively collaborative mathematics problem solving project. It was successful, so they’ve just recently started the next PolyMath project. Gowers and Nielsen have an article in Nature about PolyMath.
• The Tricki – a wiki of problem solving tricks. It’s somehow in the spirit of Polya’s book about mathematical problem solving, but much more practical, solution-centered in concrete situations. It’s something you couldn’t get with a book and it’s perpendicular to classical literature.

Usage of the terms “Web 2.0 math” and “Math 2.0″:

I have some ideas in my mind for a future Math 2.0 project, involving creative use of LaTeX, wikis and collaborative/social websites… but it will take another few months until the idea is ready to go public, and I still need to convince some collaborators to help me with the workload.

Where they talk about Web 1.0 and Web 2.0, the Web 3.0 is not far. Clearly, somebody must fill the buzzword Math 3.0 with some nonsense! Since this post is already long enough, I will speak about the semantic web, Web 3.0 and the great potential for mathematicians another time.

(And I’m really sorry that I didn’t list all good math blogs or other math projects, not even all my favourite ones, like this wonderful blog about motivic stuff. However, if I missed a popular one, I would be happy to hear about it in the comments.)

How to manage news?

It is vital to get at least some news. You need to know about political developments, to be informed when it’s time to cast your vote (or, if you’re not living in a democracy, when it’s time to protest). You need to know about developments in your work, so you can adapt and don’t risk losing your job because you’re too old-fashioned. You need to know about economy if you’re investing money. You need to stay informed about every project you want to participate in. Maybe you even need to know what pop-stars do, because if not, you have nothing to talk about with your friends.
How to cope with this information overload?

Disclaimer: if you’re using a feed reader/aggregator and/or know about Google Reader, scroll to the bottom of this post. There’s not much new for you in here.

Why information overload?
Imagine you were living in the newspaper times, without television, without internet. Then, you could read (parts of) the local newspaper every morning and that was it. No problem yet. Of course, it would have taken much longer than today, to transmit the latest information about some projects, developments in society, and so on. Since everyone has had the same conditions, it wasn’t a problem to be that uninformed.
Now imagine you were living in the television times, without internet. Then you could always get the latest “breaking news” and stock market information, and it was vital to have this information because everybody had access to this information, so you would risk a disadvantage when being uninformed. It was easy to select the information you needed, because you could just find out which channels are sending the information you want and then stick to these channels.
(Sorry for skipping the “radio” times.. here almost the same applies as for television).
What’s different with the internet? You’re no longer restricted to 100 channels sending information in a linear fashion. It’s a completely uncontrollable mess, just way to much to consume, even if you would try to do nothing else. Today, it’s not only vital to get information, it’s also absolutely unavoidable to select important information – for everyone.

Another problem that’s creeping in since the invention of radio and television is the restricted attention span: human brains are not capable of doing several things at the same time – it just looks like that because we’re able to switch very fast from one task to another. Switching tasks is a problem, sometimes. When you’re concentrating on something cognitively challenging, you will need about 5 minutes to get back to your level of concentration if you were interrupted. Another problem is, that our brain is relatively good at doing very different things in short alteration (like playing piano and drinking water and thinking about stock markets), but it’s not that good at doing very similar things in short alteration (like speaking one foreign language and then another). That means, watching TV while working does not really work for jobs that involve information processing (at least, you won’t be as good as you could).
The internet is even worse: many people have e-mail notifications, mobile phone ring tones, twitter notifications, etc., so they’re interrupted in their work very often. Since many jobs today involve information processing and getting the latest news is information processing, our brain has severe problems in doing this in short alteration.
An interesting text about the question how the internet changes the way we think can be found on the BackReaction blog.

Software can be used to control the news flood, if you use it wisely. For example, you can use an instant messenger like ICQ or Skype to let people contact you, but without an audible notification. Then you’ll only read their messages when you’re not in a state of concentration. The same applies to (mobile) phones: you should mute them for some time each day. A phone call would interrupt you immediately, while a short message is controllable by you – it’s you who decides when to digest the information.
Ask yourself: do you really need the latest latest news? Most likely it suffices to get the news some hours later, too. Instead of watching TV and hoping for not missing the breaking news, you can use feeds in the internet, so you get news immediately but are able to consume later. Feeds offer another problem solution: You don’t have to navigate to 50+ websites to know what’s going on about your favourite projects, to get your favourite opinions about politics, etc.. You just subscribe to the feed of each website and a software manages the information flow for you.

Wikipedia has a nice explanation what a web feed is. You can learn about feed aggregators/readers there, too. I’m using the Google Reader, which is a web-application, so you can use it from everywhere on any computer that has internet access. It offers collaborative features: you can select information entries to “like” them or to “share” them, if you want even with a personal comment. The software then displays on top of every entry how many people “liked” this entry, so you can use this as a guideline in the selection of important information. To “share” a news item means it’s added to a special feed, the shared items feed, which your friends or co-workers can subscribe to. This way, an organisation can effectively process the information that’s important for them and then distribute it to all members. Most aggregators offer ways to sort the various news items, so you could select some to read them later and delete some items unread.

(comic licensed from Oliver Widder under a Creative Commons Attribution-NoDerivs 2.0 License)

Feeds offer interesting ways to organise various kinds of information. If you’re a Wikipedia author, you can use feeds to watch thew pages you’ve written. If you’re using MathOverflow, you can use feeds to get the latest questions about your favourite mathematical topic (same applies to StackOverflow). Every blog in the internet has a news feed. You can avoid twitter, because each twitter account has an associated feed. Podcasts are nothing than feeds with sound- or videofiles in it.

Another software recommendation besides Google Reader is the Android software NewsRob (which works only on Android smartphones). NewsRob synchronises with your Google Reader account and is able to save the feed items (and even the websites that are behind the feed items) for later use. This is really helpful if you don’t have an internet-everywhere contract with your mobile phone provider and still want to read the news somewhere where you don’t get internet access (in a train, for example).

UPDATE: At the time I’m writing this, Google presents a new feature: Subscribe to websites that don’t even have feeds. This way you can monitor changes on any site that’s important to watch. Google creates a feed with the URL http://www.google.com/notificationservice/webchanges/webfeeds/12345.... so you can even share the feed. For those who don’t like being watched, you can exclude your site from the feature by standard methods.

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

On searching “smell file format”, the results are really absurd, too.

But this way, I came across this strange patent for digital cameras that don’t only capture pictures or videos but smells, too. Now you would think of a real odour-capture-device, but this patent suggests just a user interface to set one odour out of a list of pre-defined odours. The purpose of such a technique is clear: you can later display the image along the odour via a dispenser. Yeah … everybody has been waiting for this.

Of course, an “odour” is just a collection of molecules, since the human nose is a detector for chemicals in the air. Maybe you have never thought about this, but fishes in deep sea orientate by odour instead of light. So, an odour file format would be almost the same as any molecule file format. Maybe one could get a good file compression by knowing which molecules can be detected by the human nose and which can’t. That would be something like the list of pre-defined odours list in the patent above.

I’m pretty sure that, if it doesn’t exist today, there will be an odour file format one day.

Then I searched (again, out of curiosity) for such a dictionary which lists all smells humans can detect, together with their molecular composition. I wasn’t that successful, but at least some nice results:

• Fantastic Flavours has some nice articles about some of the most interesting flavours, with many links pointing to more information. Surely interesting for anyone who likes cooking, wine, coffee, tea, fruits, …
• The LRI & Odour database is funny to browse, too. For example, you can look for “banana” and see that bananas contain some chemicals that are also contained in melons.
• The Flavornet lists many flavours (most flavours are odours). Very interesting: the odour classes (there is a Maillard class, for example. The Maillard reaction is the chemical reaction that makes roasted food so tasty). Beware: the Flavornet crashed my Firefox, I had to use Chrome to get it working.

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)

On Linux there is no good system to annotate PDFs. There is PDFedit, which is slow and has a horrible user interface, obviously intended to be used to modify technical aspects of PDFs, not for fast annotation. There is Evince, my favourite PDF/PostScript/DejaVu reader, but the project “annotations in Evince” hasn’t come very far. And there is Xournal, a tablet PC application which is very comfortable when it comes to annotating PDFs. Sadly, it is not as comfortable as Evince when it comes to reading PDFs – and in the end I want my notes to be exportable in some open format, so they won’t get lost.

Maybe you have heard of the KDE application Okular, which allows annotations (Okular works fine under Linux and because of the nature of KDE4, it may even work under Windows and Mac OS X). These annotations are stored in an additional XML file. This has advantages and disadvantages, the advantage being that I can share the PDFs without sharing the annotations. The disadvantage, however, is that I have to stick to one program (Okular) if I use Okular annotations. I want my metadata to be included in the PDF, in the XMP format.

This problem is not yet solved even by Adobe: the Acrobat Reader (in it’s professional variant) takes annotations in an obscure closed-source format, stored somewhere else than in the PDF itself. That’s why I’m either writing notes by hand, after printing the PDF, or I’m taking notes in the Tomboy note taking application. If someone knows a solution to this disaster, please tell me! Maybe the right direction is to put the Okular annotations optionally into the XMP stream and add this ability to Evince, too.

(image “Emergency Exit” licensed from semanticwebcompany under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 Generic license)

General document metadata: author and title

Okay, let’s try to forget annotations for a moment. What about the simple metadata “author” and “title”? They’re often used in desktop search engines and document management tools, so it would be nice to have correct metadata in PDFs (and PS and DjVu files, too). How to do this with Linux? I recently spent hours investigating this question.

With jPdf Tweak, a Java application (runs under Linux, Windows, Mac OS X), you can edit nearly every PDF metadata and do much more. It is basically a graphical user interface for the iText library, which is the same library that also powers the popular command-line tool pdftk. Sadly, the interface is not really usable in editing many PDFs in a row. It also has no batch processing capabilities. If you have just one or two PDFs to edit, this seems to be the perfect tool for you. I found out that JabRef is able to write XMP metadata. Nice!

(image “Metadata sticks” licensed from Gideon Burton under a Creative Commons Attribution-Share Alike 2.0 Generic license)

My frustration with the tools available culminated in writing my own document-metadata-tool. What I have done so far is a short command-line hack written in bash and python that takes a PDF, prints it’s metadata using pdftk, asks for a new author, title, keywords, year and URI and, if something new is entered, writes this metadata into the PDF, using pdftk again. It also prints out BibTex code that includes URI and file-links, for direct import into JabRef.

This works somehow, but: the code is ugly, it doesn’t work with PS or DjVu, it doesn’t write XMP metadata (you can do this via JabRef after importing the BibTex file), it doesn’t offer a nice graphical user interface for processing huge amounts of documents and there is a strange bug so some PDFs can’t be manipulated (this seems to be related to a bug in the iText library used by pdftk and pre-damaged PDFs). If you’re interested in the code, leave a comment, then I’ll publish it here somewhere. At least for me it was very useful.

Get rid of PostScript documents

I decided to abandon PostScript files, that means I converted every PS file into PDF format, using the following shell script:
ps2pdf -sPAPERSIZE=a4 \
-dMaxSubsetPct=100 -dCompatibilityLevel=1.3 \
-dSubsetFonts=true -dEmbedAllFonts=true \
-dAutoFilterColorImages=false \
-dAutoFilterGrayImages=false \
-dColorImageFilter=/FlateEncode \
-dGrayImageFilter=/FlateEncode \
-dMonoImageFilter=/FlateEncode \
"$1" "$1.pdf"You can either save this text into a file “abandonps.sh” and make it executable via “chmod u+x abandonps.sh” or you replace $1 with the filename. Maybe you will want to use “letter” instead of “a4″, too. I’m very happy that some old PostScript documents not only load much faster after being converted but there is also (somehow magically) full-text search for some documents now!

The general solution to get full-text search and indexable documents (with Linux) is to look at another article on this blog:
Linux, OCR and PDF – problem solved

The ideal document metadata editor

I did some research on how to write an ideal document metadata editor. ExifTool, a Perl library and command-line application (for Linux, Windows and Mac OS X), seems to be able to manipulate DjVu metadata (currently only reading; when I try writing I get “Writing of AIFF files is not yet supported”). However, the company that owns the DjVu format seems to stick to their own metadata format, so XMP in DjVu won’t be available officially. To manipulate PostScript metadata it seems possible to just write a text-based parser, because the metadata is stored as plain text in the first few lines of a PS document. It may be even better to use ExifTool’s PostScript capabilities. To manipulate PDF metadata, it seems to me the best solution is to use the iText library directly (not via pdftk and the command-line, to exploit Java’s so-called platform-independence).
In general, to manipulate XMP metadata, it seems best to use Exempi, which is an open-source implementation based on Adobe’s own XMP SDK. There are python bindings available, too.
If you know of any nautilus/dolphin/other file-manager extension that already does some or all of these things, please tell me where to get this!

(*) in Germany, only parties that get at least 5% are considered for a seat in the Bundestag (with very few exceptions). There are numerous parties that didn’t reach this limit and they are subsumed under “other” and take 6% of all votes together.

As you can see, no party has more than 50%, not even closely. That’s why parties have to join together in a coalition, that reaches the 50% limit together. Technically, it’s possible that three parties join together in a coalition (then it would be effectively impossible to change politics via voting). It has happened just before the 2009 elections that the two biggest parties (CDU/CSU and SPD) formed a coalition. But that has not happened again, and as it’s usually the case, a small party joined a big party in coalition (FDP and CDU/CSU).

Maybe you notice that FDP and CDU/CSU don’t get 50% but only 14.6+33.8=48.4% of all votes. Well, this is correct (although you have to keep in mind that we are only talking about votes, not about people who are allowed to vote or inhabitants. I’m providing more numbers for this issue below). As I noted in the table above with a (*), the votes for parties that don’t reach 5% are excluded from the election counting. Yes, that’s true: If you vote for a party that’s unlikely to reach 5%, your vote is lost and your opinion who should be in the parliament doesn’t count any longer. But there are even more issues like that, so let’s wait for a moment and look at the table of votes given, excluding the “other” parties:

Now FDP and CDU/CSU have 15.5+36.0=51.5% of all votes. What about other coalition options? Just looking at the numbers, not politics, CDU/CSU+SPD would have been possible, too, with 60.5% of all votes. A coalition of three parties, FDP+SPD+GRÜNE would have collected 51.4% of all votes, so this would have been a possibility, too.

(comic licensed from Randall Munroe under a Creative Commons Attribution-NonCommercial 2.5 License)

Voting systems are designed (or at least, some people pretend they are) to give those power who are in favour of the masses. But what do the people really want? One (silly) way to look at the numbers would be: the more % a coalition has, the more people will be happy about it. Take another look at the numbers: in a coalition of CDU/CSU and FDP, there are 36.0 votes for CDU/CSU, thus 64.0 votes against CDU/CSU, and there are 15.5 votes for FDP, thus 84.5 votes against FDP. This means, strictly thinking about the numbers, that 64% of all votes are against this coalition.

You might say now: “maybe the votes for FDP have had CDU/CSU as their second choice?” and this is the right direction to look at. We’re not counting second or third choices now and this poses several problems. If we’d ask the 6% of voters who were ignored because they’ve voted a small party, what their second choice would be – it may change the outcome of the elections. Imagine that half of the other-party-voters would have chosen the LINKE as second choice (this is an estimate which might be close to reality) and the other half is distributed like the other votes. Look at the changed vote table then:

You see that FDP+CDU/CSU have now 15.1+34.8=49.9% of all votes. This is close, but not equal to 50%, so they could not form a coalition. This is just a little example to show what’s odd in voting systems.

Maybe you’re sitting in front of you computer, muttering “of course different voting systems lead to different outcomes, what’s wrong about it?”. In my personal opinion, a voting system should be designed in a way that the common wishes of the group are expressed in the result. Interestingly, mathematics tells us that this is impossible in many cases, especially if there are many options for a vote with a close outcome. The current voting system in Germany encourages strategic voting, which is voting a party (more generally an option) you don’t prefer most, knowing that the mathematics add up so your real preference will win more likely because of your vote. It’s even possible to weaken a candidate by voting for him. In the interesting Bush/Gore presidential election in the US, it’s pretty sure that Gore would have won if Nader (the third candidate) wouldn’t have been an option to vote for.

From the book “Chaotic Elections” you can learn that amongst all positional voting procedures, the one the least manipulatable by strategic voting is the Borda Count. For this procedure, you have to ask the voter about his second choice, and even his third, fourth (and so on). This sounds complicated and I don’t think it’s feasible yet for national votes. Maybe it suffices if we require to name a second choice. It does not suffice to open the possibility of naming a second choice – people don’t use this opportunity very often (this has been seen in experiments). That’s because almost nobody knows about voting paradoxes and how to create and avoid them. So we all are very manipulatable if we don’t learn how elections work, mathematically. However, manipulating elections by choosing a specific voting procedure or by strategic voting is not the only method of manipulation in democratic settings: imagine wrong statistics (or even no statistics) provided by bureaucracy or manipulative nomination, which includes strategies like “I propose something very close to what everybody likes, but I bundle it with something everybody hates – then nobody will vote for it”, which work if similar proposals are gathered to facilitate voting (in particular, the german e-petitioning system is vulnerable to this attack).

Some more numbers of general interest:

• total population, in millions: 81.8
• people allowed to vote, in millions: 62.2
• people who actually voted, in millions: 44.9
• people who did not vote but were allowed to, in millions: 17.3
• people who did not vote, including those not allowed to: 36.9
• percentage of actual voters in total population: 54.9
• percentage of people who voted for either CDU/CSU or FDP
  in total population: 26.6
• percentage of people who voted either CDU/CSU or FDP
  in population allowed to vote: 34.9
• percentage of people who didn’t vote either CDU/CSU or FDP
  in population allowed to vote: 65.0

the most interesting number, for me, is the last one. It indicates that 65% of all people that are allowed to vote could have changed the outcome of the vote if they would have had been asked for their second choice. Maybe asking them (and counting with Borda Count) would have shown that CDU/CSU+FDP was a common choice – maybe we would have had a completely different parliament in Germany now. It’s always questionable why 17.3 millions of Germans didn’t vote although they’ve had the right to do so. Maybe they knew that they couldn’t vote for their favourite party and change politics at the same time.

(comic licensed from Randall Munroe under a Creative Commons Attribution-NonCommercial 2.5 License)

I looked up the numbers used here from different statistical services and newspapers. All numbers are from 2009. Every number is either checked twice or calculated by myself. But beware: those are statistics, you’re not supposed to trust them!

There is a review about the book here, if you’re interested now.

There are many, many other voting paradoxes which can happen and affect our life, in every situation involving a democratic process with more than 2 options (**), which happens quite often. I recommend you to read something about this subject, maybe something shorter or better digestible than Saari’s book – but if you’re interested in politics, social phenomena or mathematics (or anything in-between), I guess it’s best to take a look at Saari’s book. It has parts which require you to understand some basic calculus, but in Germany you learn all this in the last years of highschool. Even if you ignore all calculations, the basic problems are well explained. I myself took some calculations for granted, since I began to trust the author after some examples turned out to be correct

The most provocative quote from Saari, from page 100 of the book:

For a price, I will serve as a consultant for your group for your next election. Tell me who you want to win. After talking to the members of your organization, I will design a ‘democratic procedure’ which ensures the election of your candidate.

and after reading the book I have to admit that it’s not a big challenge. Once you know the voter’s preferences with a certain probability, you’re able to design some voting system that “chooses” your favourite option. That’s why most democracies tend to stick to one voting procedure instead of changing it for each election (and gerrymandering is a popular example of such manipulations).

(**): Little exercise: why aren’t there any voting problems or paradoxes when there are only two options?

How to manage papers?

I have lots of PDFs on my hard-disk, and most of them is half-read or unread. Since I’m studying mathematics, these PDFs are lecture notes, research papers, my own notes and several more-or-less relevant books. How do I organise them? It’s a problem.

I separate my own notes from everything else, and keep my own PDFs with their LaTeX source in the same folder, these folders are sorted by subject. The other PDFs fall in 3 categories: the relevant, the irrelevant and the books. I keep all books in one big folder and use search to find something specific. The irrelevant PDFs are just somewhere floating in my computer – on my desktop and in various folders called “papers”, “some papers”, “more papers” and “maybe read”. The relevant PDFs are re-named to make them easier to find with a desktop search engine (I usually put the authors name, some keywords and the year in the file-name) and they’re sorted by subject in folders. I consider this a very bad solution.

So I have a second system: JabRef, which is an open source reference manager (and BibTeX database editor) written in Java, so you can use it on Windows, Linux and Mac OS X. In JabRef I put every book or paper I want to cite somewhere or that I think of being that interesting that I just have to keep one more safe reference. JabRef allows to link BibTex entries to files on your hard-disk. This way you can forget about where you stored your files.
Interesting fact: Google Scholar has a setting to enable BibTex export – which you can use together with JabRefs BibTex import for very fast database creation/updating. Sadly, the Google Scholar metadata is wrong sometimes…
Another interesting fact: there is a Bibsonomy plug-in for JabRef. Sadly, it doesn’t work for me (I don’t get it how to install it under Linux). Bibsonomy seems to be used almost exclusively by computer scientists, especially those working on semantic web stuff.

It’s strange, but I have a third system: a huge spreadsheet in Google Documents, where I keep all the papers and books that are related to something I want to learn in near future. I keep track of dependencies, that means I use this spreadsheet to find out which paper/book I have to read first in order to understand the second. I also attach some relevancy score to each item. Finally, some insane formula calculates a ranking across all items which tells me the top 3 papers I have to read next. This works (at least after I adjusted the formula long enough so that it displayed what I already knew was important). I’m currently thinking about replacing this system with CiteULike, because you can enter a reading priority there, too.

For Wikipedia users, the reference management system Zeteo might be of interest. You can’t have user accounts there, but easily manage references for later use in Wikipedia. Funny: it turns out it’s written by someone working in my math department!

(image “Dropbox Upgrade” licensed from Scott Beale under a Creative Commons Attribution-Noncommercial-No Derivative Works 2.0 Generic license)

It’s no fun to “maintain” three systems, one messier than the other. I’m currently thinking to just move everything over to JabRef, but this doesn’t resolve the “storage” problem. Maybe one big folder that contains it all, combined with desktop search is the best solution. Maybe it would be cool to store the papers on-line, in Ubuntu One, for example. But I wasn’t bold enough to try, yet. Maybe it’s good to keep track of references in some Web 2.0 tool, like Bibsonomy? I haven’t tried either. I think it is a good idea to remove any PDFs from your hard-disk that are available without restrictions (like arXiv papers) that you don’t need in the near future. The less there is, the easier it is to manage it. If you have any suggestions, I would be very happy to read your comments.

SaveYourSolvs is the new Solvr interface that keeps track of your discussions.

If you’re a Solvr user, this might be useful. Maybe you find the Greasemonkey Userscript for SaveYourSolvs integration into Solvr useful. You’ll need the Greasemonkey Firefox Add-On for this.

How to use SaveYourSolvs:

• try out the minimalistic interface for SaveYourSolvs
• the username is the key: change it to some alphanumeric password (but, please, not some password used elsewhere)
• in the Greasemonkey script, change the username from “sandbox” to your password-username
• it’s up to you which fields (name, problem, uri) you use, you need only one to generate a new solv
• with the Greasemonkey script, navigate to your old solvs and add them to SaveYourSolvs easily
• the field “uri” means the part in the solvr uri that comes after “solvr/d/” but before the optional “?problem=…”
• the field “problem” means the part in the solvr uri after “?problem=”

It’s easy to use, as you see in the screenshots:
(Click to enlarge the images)

If you’ve got any questions, ask them at the SaveYourSolvs discussion in Solvr (or here, if you prefer).

For developers:

• you can use the apps sys-list.php sys-creator.php and sys-rest.php as well
• all three apps respond to the same GET queries like the main interface
• but only sys-rest.php displays almost nothing.

• the Greasemonkey script can easily be changed to point to delicious instead of SaveYourSolvs.
• UPDATE: in fact, I have done that. Look at the new Greasemonkey script, which provides more social bookmarks.

To be honest: I think using some bookmark service like del.icio.us is better than using my tool. I just wrote it to get an impression how PHP+MySQL works (and how insecure it is) and how easy it is to manipulate the HTML DOM with JavaScript (in the userscript).

As soon as I release the sourcecode, I will have to stop the service on the webserver since I don’t know enough about PHP security issues. Maybe the Greasemonkey script is useful to learn quickly how to write such userscripts