# The Spectre of Math

## May 27, 2010

### Never use Chase bank!

Filed under: Personal — jlebl @ 9:49 pm

So I just found out that Chase has just subtracted another monthly payment from my checking account for a car loan that was paid off two months ago. Apparently, once you set up automatic payments, they are impossible to cancel. Also now the account is dead so I cannot access it and they said they can’t cancel payments either. I didn’t quite understand when they will give us back our money. I went to my bank and they said it’s not possible to block future payments to chase without a stop payment fee.

I did cancel the automatic payments (I don’t understand why you need to do that since the account is paid off) when the account was paid off. But that only canceled the April payment and not the May payment, and apparently now they will keep taking our money.

So the lesson is: never, ever, use chase as your bank, including for a loan. In case it is chase that does your auto (or some other) loan, make sure to never give them your account information to set up automatic payment. Perhaps it’s easier to just not get a loan with chase.

This follows their earlier nonsense of taking out more than the payoff amount on the last payment and then having to give us back a check for the difference.

### Chrome vs. Firefox

Filed under: Linux,Technology — jlebl @ 4:02 pm

For the past month or so I’ve used Chrome to test it out. At first I thought it worked really well. Then I’ve started to discover many annoyances. Firstly, there is no way to “open” files like PDF directly from the internet. Chrome forces you to click a whole bunch of times so that you download the PDF to the tmp directory, then you open it by clicking on the name on the bottom of the screen. This is really, really, really annoying. Especially for a mathematician (or I assume any scientist) who reads many PDFs, DJVUs, PSs, every day. This is enough to make me not want to use it. Whatever stress reduction from slightly faster and smoother browsing experience is totally canceled out by this. I really don’t see how hard it is to save to /tmp and open automatically. I mean browsers have been doing this forever.

Another thing that was worrying me is that saved passwords are not encrypted behind a master password.

The last straw was the fact that it can’t print right.

So back to firefox. Yes it’s slightly slower, and every once in a while I get weird JavaScript errors when using gmail, but it’s way less annoying. It will be nice once firefox moves to separate processes for every webpage. I think that alone does quite a bit to speed up browsing, especially one a multicore machine.

So the result of the fight: Chrome-Firefox is 0:1.

### Ubuntu vs. Fedora

Filed under: Technology — jlebl @ 3:42 pm

Before I go off to Europe, I wanted to reinstall my system with an encrypted hard drive since I am getting more and more paranoid about someone stealing it I guess. So apparently I must have been bored since I decided to install Fedora this time instead of simply going with Ubuntu.

One thing I have to say is that I like the default look of Fedora way nicer than Ubuntu. The purple login screen was already giving me nightmares. The other thing that I’m really happy about is that X is actually working perfectly. With Ubuntu it was touch and go and every once in a while it would recognize the wrong number of monitors or wrong resolution. Given that Ctrl-Alt-BS no longer works by default you have to work blind if the login screen appears on a monitor that doesn’t exist. Yes I know you can enable Ctrl-Alt-BS, but that’s only for your login session. I never got it enabled for GDM (I didn’t try to hard, but what I tried didn’t work). I never understood why Ctrl-Alt-BS is so bad that it has to be off by default. It is not a combination I ever pressed by mistake. I’ve also never stabbed myself in the throat with a drill by mistake, or accidentally strangled myself with the phone cord. I assume those are about as likely as pressing Ctrl-Alt-BS by mistake.

Outside of a few minor glitches it is mostly working. One should also note that Fedora installs a broken LaTeX system with a few key files missing due to some license puritanism. For one thing, pcatcode.sty is missing. You have to grab it from a working installation and stick it in /usr/share/texmf/tex/latex/amscls/ and then run texhash. Otherwise the AMS classes won’t work which means that the latex installation is useless to a mathematician. On the other hand floatflt.sty is not missing while it is missing in Ubuntu for licensing issues. Fedora still uses texlive 2007. It seems from Fedora wiki that the next fedora will have texlive 2010.

One thing to notice is that even after enabling extra repositories, there are lots of packages missing. Oh well. The other thing to notice is that the GUI interface for installing packages in Fedora sucks! … no really, I mean IT SUCKS. It feels like it was written by a 12 year old. I’m sure the infrastructure behind it makes CS types all warm and fuzzy inside, but the GUI is terrible! While way too much information about the package version and other implementation details are seeping through the GUI, it gives you NO feedback as to what it is doing. The feedback it is giving you is useless. Sometimes it refuses to install anything without even complaining, the Apply button is just dead. Either make it something like synaptic (which has it’s own GUI nonsense) OR make it user friendly. You can’t simply take the worst of both worlds and stick it together.

The encryption (it’s the whole drive that’s encrypted) is actually reasonably transparent. Copying lots of files (moving my home dir back onto the drive) slowed down the whole machine to the point of being useless, but that might be simiar without encryption, since it seemed most of the slowdown was waiting for the disk. Given that it’s a two core machine, I doubt I will see much slowdown in most tasks.

## May 24, 2010

### Hockey world championship final game not interesting here

Filed under: Personal — jlebl @ 1:50 pm

So yesterday it was the final game in the hockey world championship, and it was not on TV here. All I can say is WTF? I don’t normally watch hockey (or any sport), but a finals game I wanted to (especially since czech was playing … and won). It seems that everyone is pretending the championship doesn’t exist simply because US didn’t get far enough.

I had to watch the thing in really bad quality on the internet in danish.

An interesting statistic is that in the past 20 years (ever since Czech republic existed that is), Czech won the most times (6), Canada 5 times, Russia 3 times. So hardly the underdogs nowadays, even if Russia is rated better.

## May 20, 2010

### Sourceforge.net for Math Texbooks

Filed under: Mathematics,Teaching — jlebl @ 8:12 pm

I mailed our faculty mailing list touting my textbooks (Diffy Qs and Real Analysis), and one of the responses linking this post gave me an idea. Perhaps I should start a sort of sourceforge.net for math textbooks. Simply set up a repository (svn would work best I assume). Then set up some web around it. The site would definitely need some “editorial board” that would approve what textbooks are allowed, and there should be some sort of way to make versions that are “blessed” by the board and that would then be in some sense “stable.” Books could be in development and of course branches could be set up to work towards the next “blessed” version of the book.

I would definitely want to avoid the problem of wikipedia, wikibooks, planetmath, and such, where anyone off the street can come in and start typing what they think is math. The problem of wikipedia is of course that anyone can do whatever they want. Planetmath was touted as being more strict and having maintainers for topics. The problem with planetmath is that the way maintainership is decided is on a first come first serve basis. If the homeless guy living in the local mall parking lot decides that he wants to write a topic on strictly pseudoconvex manifolds, then he will control that topic from now on. Regardless of qualification.

## May 17, 2010

### Texas textbooks and communism

Filed under: Politics — jlebl @ 1:41 pm

Ahhh … this brings back memories. Growing up in communism, I saw all kinds of indoctrination in the textbooks. Though some of these Texas changes are even more than the communists ever tried. In my textbooks it was essentially Czech exceptionalism with a bit of Russian and pan-slavic exceptionalism thrown in for good measure. Replace “free market enterprise” with “centrally planed economy”. You can keep the bit about that system leading to “liberty” that bit was the same in the books. It is interesting that Texas education board is downplaying democracy while the commies kept yapping about it. I guess it is just due to the unfortunate naming of the Democratic party. The whole Reagan-orgy is also familiar, though it was Gottwald for us.

We always thought that it was those evil commies that had a bunch of politicians dictate school curriculum. We thought: “in the west where there is real democracy and freedom education is left to the experts and educators. History textbooks are written by historians, economy textbooks by economists, etc…” HA!

Yes I know the members of the board are elected, but they are politicians. But history is history, it is not dependent on who holds some political office. You can’t write history by asking what do people want history to be. Well … apparently you can.

## May 11, 2010

### Yay! End of semester!

Filed under: Mathematics,Personal,Teaching — jlebl @ 9:01 pm

It is finally end of semester. Still have to grade some finals, but other than that, I’m done. It’s also the end of my time at UIUC, next year I’m off to UCSD for a year.

I finished off, at least in a rough draft sort of way, my notes on Hermitian forms and CR geometry, a half semester minicourse I gave at UIUC. Perhaps those will be useful to others. I can’t really say that they will be “bug free,” I am sure there are many typos. There are even some previously unpublished results (though probably previously known). For example, suppose that you have a real analytic function $r(z,\bar{z})$ such that the series (in multiindex notation)

$\sum_{\alpha,\beta} c_{\alpha \beta} z^\alpha \bar{z}^\beta$

converges in the neighbourhood of the unit polydisc (converges absolutely at the point $z = (1,1,1,\ldots,1)$). Then the Hermitian matrix $C = [ c_{\alpha\beta} ]_{\alpha\beta}$ defines a bounded operator on $\ell^2$ (actually it defines a compact operator). For a long time I was always doing all these matrix operations with the coefficient matrices formally. And then you have to be very careful. Once you rescale so that the coefficient matrix is a compact operator, then it’s just like doing linear algebra, and all the subtleties go away.

I also kept updating the differential equations notes like crazy this semester. The students could have gotten up to 3% extra credit for finding errors, but only a handful did. Majority of typos I found myself. The good news is that the notes, especially chapters 0,1,2, and 4 are reasonably bug free. Chapters 3,5,6 also got some bug-spray treatment, but not as much. I still have a bunch of minor grammatical errors pending and I’ll wait for a week maybe before putting out another version just in case somebody still finds some more.

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