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Name: Jiri (George) Lebl
Member since: N/A
Last Login: 2009-08-27 18:51:39

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Homepage: http://www.jirka.org/

Notes:

Math geek, formerly software geek. This exhibits itself by putting latex code into C programs by mistake, rather than vice versa as used to happen previously.

Credentials: Mathematics: I have successfully used the Baire Category Theorem in actual research. See my UIUC page for more.
Coder: I have created more easter eggs in gnome software than anyone else at the time. For example, Wanda the fish, which appears in more than one place if you know where to look and what to press, gdm computing square root of 2 or pi by monte carlo method, asking for coins on login, killer gegls from outer space, and more... At various times I was actually paid for this by Eazel and RedHat.

Below it says I'm a developer in a buttload of projects, but I'm not really anymore on anything but genius, since I don't have much hacking time these days.

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Windows 8.1 innovations

I’ve just briefly glanced at what’s new in Windows 8.1, probably because I am procrastinating right now, not because I am actually interested, not having any plan of ever using Windows ever again in my life.  It was really amusing that new features are apparently that you can open more than two applications at once and also resize them on screen.  So maybe Windows 8.1 will finally catch up to Windows 1.0.

I feel I’m taking crazy pills here, because almost everyone is really into this trend.  First make the interface really bare (but graphically intensive) to make it look like a smartphone.  Then reintroduce very restrictive versions of these features and tout them as great achievements.  Chrome OS also at some point caught up with the 80s and added stacking windows.  I wonder when Windows will finally get into the 80s.

And while basic features like window management appear an insurmountable challenge in the new “iphone app” mentality, putting up a clock on your screen eats more CPU/GPU and memory than it would take to guide a spacecraft to Mars and back.  Not even that long ago did a calculator application not require 3D acceleration to reasonably run.

Good thing I’m using XFCE here.  Let’s see how I start a calculator: My non-accelerated desktop means that if I press Ctrl-Alt-R (which is my shortcut for terminal … R used to stand for rxvt long time ago) I immediately get a terminal.  Then I type “genius” press enter, and I’ve optimized the startup so I get a prompt immediately, there is essentially zero wait.  I type in a calculation, and out pops the answer.  Now if I attempt to do this on my phone, or in GNOME using the native calculator, there are several long waits either when some random nonsense is loading just for me to start the app and then there are these useless animations taking up time.  So for example if I have a student in my office and want to just quickly (note the word quickly) calculate something about their grade, I would definitely not do it on my phone.  Even try starting the native terminal in GNOME, it’s a few seconds wait on my machine from the time I get to start it (click a button, or whatnot).  So much for accelerated desktop. Just trying to phone someone on my phone is often a lot longer process than it used to be in the 90s when I got my first cellphone.  There is hardly a lack of power in the phone, it is just that it is so skillfully wasted.

This younger generation today must be really really patient (compared to us old fogies … you know 35 is old when it comes to technology) to put up with this.


Syndicated 2013-05-30 16:35:48 from The Spectre of Math

Computation update

On the scale of length of computations I’ve done, this probably counts as the longest so far.  If you look down a bit in the blog you’ll find the details.  I can now report that there is no degree 21 polynomial p(x,y) with positive coefficients, with exactly 12 monomials (the least it can have), such that p(x,y) = 1 whenever x+y=1, and such that xy is one of the monomials.  Now the conjecture is that there is only one such beast (up to switching variables), dropping the condition about xy, and the computation is well on its way to prove that.  That one monomial is a bit special since it appears in these sharp polynomials for a bunch of smaller degrees.  Anyway, a few more months and we’ll have the answer.


Syndicated 2013-05-28 16:45:05 from The Spectre of Math

Math is a series of trivial observations

Mathematical proof is essentially a series of completely trivial observations wrapped in complicated-sounding notation (not complicated on purpose hopefully). The trick is not to understand the proof once it is written, but to notice those trivial observations to write a proof in the first place. I think this is what’s sometimes discouraging people from research mathematics. You work for two weeks on something that feels like a very hard problem, and then the solution seems trivial once found. In my case there are two operations and a limit involved. And the things you are trying to bound are not continuous with respect to that limit, so you flail around trying to do all sorts of complicated schemes. Then last night I think … hey why not do these two operations in reverse. I get rid of the limit and the problem becomes almost trivial after a bit of linear algebra. It feels good. But on the other hand it feels like: Why didn’t I think of this two weeks ago.


Syndicated 2013-03-29 16:38:56 from The Spectre of Math

Moving to Oklahoma

So, moving to OSU in Stillwater in the fall. This entails for the first time in my life quitting a job before it sort of naturally ends. The consulting gigs don’t really count I don’t think, and Eazel laid me off in the process of going under, so that counts as natural end of a job. At Red Hat it was just a summer gig, so there was no expectation of staying longer. Then at SDSU and UCSD I was a grad student, so any employment also ended when I graduated. In Urbana, they did make me send a “resignation letter”, but my appointment ended anyway as I stayed the whole 3 years I was hired for. At UCSD then I was hired for 1 year and stayed for one year. So now … I was hired for 3 and I am leaving after 2. Six years of postdoc in 3 different places are enough I think. One can always keep changing jobs every few years, but it’s nice to know I don’t have to now, I just can if I want to.


Syndicated 2013-03-11 20:06:18 from The Spectre of Math

The computation

So the computation has finished (actually a few days ago) for degree 19. I’ve only yesterday gotten around to finishing a short paper (addendum) to post to arxiv, which I’ve done yesterday, see arXiv:1302.1441. The really funky thing is that there are so many sharp polynomials in degree 19. Up to symmetry there are 16 in odd degrees up to degree 17, yet there are 13 in degree 19. And two of the new ones are symmetric, which is actually surprising, that seems it should be hard to achieve if you think about how they are constructed. There’s probably a bunch of interesting number theory that appears here. It should be fun to figure out what’s going on there.

This was the first time a paper of mine got reclassified to a different archive on arxiv. I put it into algebraic geometry because well, the motivation comes from geometry, but it got stuck into comutative algebra. Which actually makes a lot more sense. Especially since none of the motivation from geometry appears in this writeup.

Degree 21 has been running for about a week. It will probably be running for the next year or so at which point I really expect it to just spit out only one polynomial which is the group invariant one we already know about. Which would be also kind of funky since then there would be two degrees with as few polynomials as possible and in between there would be a degree with the most polynomials we have found so far in any degree.


Syndicated 2013-02-07 16:47:48 from The Spectre of Math

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