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posts about math.

over the last weeks, i’ve been starting to convert my blogs to nikola, a static blog generator named after nikola tesla. so far, i’ve finished my math blog and musikwiese. i also got rid of the fixed width layout. spielwiese itself will take a bit more work, mostly because of the wordpress plugins i wrote and heavily rely on throughout this blog.

to convert my blogs, i had to add some changes to nikola. most of the core changes are now contained in nikola itself or are close to be integrated (except xhtml support). i also worked a lot on improving its wordpess import, which so far wasn’t very helpful from my point of view. for that, i created a wordpress page compiler for nikola which essentially does the same to posts as wordpress’ formatter does. that part is still not completely done, and since it is a pure plugin, i haven’t released it yet. (that will happen later, hopefully still this year.)

the main disadvantage of the whole conversion process is currently that there’s no more possibility to add comments. all comments written so far are preserved, but currently there’s no support for adding new ones. i’ll try to figure out a good way to do that later. the “standard way” to do that, i.e. using something like disqus, is not acceptable for me, and even though there are free alternatives for self-hosting, i don’t like to rely on javascript for such things. for the moment, you have to send me an email if you want to add a comment to musikwiese or my math blog.

two days ago, alexander grothendieck, one of the greatest mathematicians of the 20th century, died. i’ve seen a small excerpt of his work in algebraic geometry and commutative algebra during my studies, phd and postdoc times. without his work and ideas, the theory of schemes wouldn’t be what it is today, and without it, the study of elliptic curves over rings might have taken quite a different road. (elliptic curves over rings are a topic i’ve been very interested in while working on my diplom thesis.) even though his active mathematical career stopped over 40 years ago, his work had an immense influence on generations of mathematicians.

rest in peace.

(a great obituary can be read at the telegraph.)

already two and a half weeks ago, scott vanstone died at age of 66. scott intensively pushed, commercialized and invested in elliptic curve cryptography from its beginnings on. he also co-founded the ecc conference series, which i attended eight times.

rest in peace, scott.

posted in: daily life math
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last week, we visited tromsø in arctic norway for a couple of days. it is one of the largest cities north of the arctic circle, featuring a university (which, among many other subjects, also has a mathematics department – to my knowledge, the only one north of the arctic circle).

tromsø during daylight.

here are some impressions from tromsø during daylight. at this time of the year, there’s not too much daylight – the sun rises around 10 am, and is gone by 4 pm. the photos feature the tromsø gallery of contemporary art, the polaria aquarium whose form represents ice floes, the rica ishavshotel with its interesting form, the polstjerna (a seal hunting ship) museum, and some views on tromsø’s harbour, in part from the tromsø bridge:

tromsø at night.

most of the time, we saw tromsø during night. this is how it looks. the first picture shows the public library.

the last four pictures depict one of the hurtigruten ships, the trollfjord which was stopping by in tromsø one night. we used the chance to explore the ship a bit and have a nice midnight snack on-board.

northern lights over tromsø.

unfortunately, we only saw an aurora once during our stay. but it was a beautiful one! we were standing close to the public library, and later to the city hall:

polaria.

we also visited the polaria, the northernmost aquarium featuring bearded seals. here are some impressions from their feeding and training session:

tromsø airport.

finally, on our last day in tromsø, the weather was fantastic. that is, there was a lot of sun and not many clouds around noon. we were already at the airport at that time, but still managed to take some nice pictures:

last week i was in leiden, attending a workshop on post-quantum crytpography and quantum algorithms at the lorentz center. it was a collection of talks and working in smaller groups, where we discussed certain topics, such as quantum attacks on ideal lattices in more detail, trying to find a way to use quantum computers to speed up attacks against primitives of post-quantum cryptography. as this is somewhat close to my research – i work on analyzing a quantum algorithm with pawel wocjan and am working on lattices and lattice reductions – i was very happy to attend this meeting. especially since there were not just some mathematicians, but also a lot of experts on various aspect of quantum computers and quantum algorithms. now i also know a lot more about quantum computing, both from the theoretical side – like having been explained grover’s algorithm, which is another of the fundamental quantum algorithms next to the period-finding algorithm family starting with shor’s algorithm – and the practical side – what the current technology with regard to building quantum computers is, and how people writing compilers for quantum computers can suffer and how complicated it can be to turn a “simple” algorithm into a circuit. i think this was one of the most productive workshops i’ve ever attended.
unfortunately, i neither took my camera with me (the little one i had with me last week, since it is somewhat broken (the sd card slot won’t keep the card anymore, similar to what is described here), nor did i really had time to take any pictures, as i spend most awake hours doing mathematics. i took a few shots with my mobile phone on the excursion/conference dinner on wednesday, which happend to be on a boat going through grachten around leiden and the city and also happened to be a very decicious and very spicy asian food buffet. and later, there was a great dessert buffet. one of the best and original conference dinners i had for quite some time :)

this friday, our math institute did an excursion to the üetliberg. we took up the cable car at felsenegg, had a drink or ice cream in the restaurant there, and then walked over to the uto kulm, where we had a nice dinner. from there, we took the train back down. the weather was very nice in the beginning, even though rain was predicted and there was a lot of rain in the morning and the night before. while sitting at the restaurant near felsenegg, clouds came up, giving a nice shade for the walk. inbetween, it also rained a few drops, but that was almost welcome as a refreshment. after being at the uto kulm for a bit of time, having a nice apero outside, we were able to enjoy a nice rainbow over zürich. as we went inside, it started to really rain outside. in the night, when we left, it was dry again. i’d say, perfect weather for an excursion! only for the photos, there could have been more sun :-)

someone just sent around this link:

[[for legal reasons, i do not want to include youtube videos here anymore. please click on this link to watch the video at youtube.]]

(theoretically) infinite pendulum fun with a period of 60 seconds (since gcd(51,52,…,65)=1)!

posted in: math
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some time ago, a friend borrowed me his copy of logicomix, a comic on logic i heard a lot of good about from various friends. yesterday, i finally got around to start reading, finishing it today. i must admit, the idea of telling the quest for finding a foundation of logic, of mathematics, in a comic sounds somewhat strange, like a hopeless endeavor. but my friends were right: this comic is excellent! telling a story in a story in a story, sometimes with less layers, introducing all important characters of this quest, whose names are familiar to most people interested in mathematics, logic and philosophy, this comic manages to present the quest for foundation of logic and mathematics in a nice, easy accessable way. lots of explanations here and there, hidden as story elements, as well as an appendix containing more information on certain topics as well as the involved persons, hopefully help readers with less background than me.
if you get a chance, read it! even if you are no mathematician, logician or philosopher. it’s worth it.

posted in: math
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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.

posted in: daily life math
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