this week, i attended the seventh international workshop on coding and cryptography, held in paris at the institut henri poincaré. besides the three hour visit to paris in 2007, this was my first real visit to this city. the weather was nice, it was sunny though not too warm, and from times to times a bit cloudy (like on the free afternoon). i mainly roamed through the latin quarter up to the seine, the louvre being essentially the farest point away i’ve been at. i had my small camera with me on some of these trips, so here are some impressions.

i also went for a walk during night, once with a camera and once without.

out of the following three churches, namely the saint-étienne-du-mont, the notre dame de paris and the panthéon, i entered the panthéon and inspected notre dame in more detail. unfortuntely, i didn’t really find out when i could enter the saint-étienne-du-mont…

the following shots are from notre dame.

the last shots are from the panthéon and its crypt.

ps: if you want to eat at an excellent place in paris, try out the les papilles.

some of you might know harro heuser, a german mathematician. he is famous among students for his introductionary books on analysis, which explain very well and in great detail many aspects about the analysis which is taught to students of mathematics in the first year.

today, i was informed that he passed away.
rest in peace.

one thing is for sure: he won’t be forgotten by the next generations of mathematics students, since his textbooks are still some of the best ones available.

today i saw a movie, called flatland, based on a 126 years old novel. a must-see for any mathematician (or must-read). it’s about politics. about thinking. about imagination.
in flatland, a two dimensional world, the third dimension is known as a myth, and it is forbidden to talk about it. there are hints, which are well-hidden from the public by the rulers. until one day, little hex went out to see these hints, and her grandfather, after having more than dream, in more than two dimensions, tries to protect her.
apparently, the movie is much easier to digest than the novel.
another reason to read that book.

after attending the joint mathematics meetings in san francisco, i want to share two points you should not try to copy when you’re organizing a conference.

• in case you have a lot of parallel sessions, try to schedule sessions with similar topics in parallel. this minimizes the number of days people from these areas have to attend the conference.
• promise wireless internet, but do not provide a backbone which can handle this. after noticing it is too slow, simply turn it off for the rest of the conference.
• this applies more to conference center owners. do not install power plugs anywhere near to areas where tables and seats are placed. and by any means, never install power plugs in rooms where talks are held.

people will really appreciate this and regard your conference as one of the best ever.

the last two weeks were pretty much packed with two conferences and a summer school. on august 13–14, i.e. thursday and friday, the selected areas of cryptography conference was held in calgary. then, the week after that, the ecc summer school was held from wednesday to saturday, and from sunday afternoon to wednesday the 13th workshop on elliptic curve cryptography was held. (in fact, this was the sixth ecc workshop i attended, beginning with the one 2004 in bochum. and the second ecc mentioned in this blog; apparently i was too busy to write something about the 12th one held in utrecht last year.)
in addition to these things, several more things happened, some about whom i might write a few words in some more posts.

as you may have noticed, i use wikipedia a lot – both for linking to descriptions of terms i use in this blog, and for looking up stuff myself which i encounter somewhere, may it be offline or online. usually, chances are good that wikipedia offers at least some kind of description which answers my questions, or at least helps me getting an idea. but from time to time, it happens that you try to look something up on wikipedia, only to find out that such an article existed but was deleted – for example, because it was “not relevant”. i can understand that people do not want to see wikipedia flooded by biographies of john doe and jane roe – only a handful people are interested in these, probably most notably john doe and jane roe themselves.
but there are cases where i simply can’t understand the decision. for example, there is the chilenian doom metal band mar de grises, which i discovered by chance in zurich’s now deceased knochenhaus. according to the wikipedia deletion log, it is “not noteable” and failes some guidelines. so, who decides what is noteable and what is not? and, after all, the simplified ruleset explicitly mentiones

ignore all rules – rules on wikipedia are not fixed in stone. the spirit of the rule trumps the letter of the rule. the common purpose of building an encyclopedia trumps both.

i can pretty well understand that not every small band hobby band project should be mentioned – in particular the ones which sound bad and dissolve quickly with none or almost no productions. but that’s not the case for mar de grises. besides that, the deletion log also mentiones other problems with the article (namely, being badly written and failling to provide references for some claims), but why not throw these parts out or reduce the article to a stub?
two other examples, this time from the german wikipedia, are sinnlos im weltraum and lord of the weed, two fandubs. according to the english wikipedia, sinnlos im weltraum (a redub of a star trek series), dating back to 1994, is one of the first such projects, essentially starting the whole genre of fandubs. i don’t know how many people know it, probably a huge number. lord of the weed (a redub of the beginning of 2001′s lord of the rings) is also rather well-known; i don’t remember how often i saw it – at least ten times. well, it is obviously true that these movies haven’t been shown in movie theaters or on television – as they contain copyrighted material (i.e. the original movie), used without permission. for the same reason, they haven’t been shown on film festivals, you can’t buy them on dvd. they are also not listed on the imdb. but – so what? does that make them not noteable? irrelevant?
on the other hand, a lot of totally trashy movies – which, compared to sinnlos im weltraum and lord of the weed, are really crappy and lame – are featured on media, two good examples are a music video by grup tekkan and the infamous star wars kid, making a fool out of himself. these are pushed by media as “youtube movies you have to see” or are even shown on tv. and they can be found on wikipedia. even though they are real crap. in the case of star wars kid, the really embarrassing movie was uploaded by “friends” of its actor and will probably haunt him for a very long time. to make this even better, a lot of online versions of famous newspapers or magazines feature this video as well, showing it to an even wider audience. and i thought the use of a pillories are outlawed in modern countries.
anyway. i’m still using wikipedia, even though of these reasons. and i even created an account at the english wikipedia and started writing an article about infrastructures (number theory). as so far, nobody else dared to write something on this subject, and a google search only gives documents featuring other kinds of infrastructures, or scientific articles about this subject, i thought it would be time to add something to the web. i’ve started a series of posts on my math blog on infrastructures, but as google usually ranks wikipedia articles higher, i decided to also add something to wikipedia. so far, it is more a stub and far from being a complete article, but at least provides some information and several references to literature.