## Search found 98 matches

- Wed Nov 06, 2013 6:04 pm UTC
- Forum: Serious Business
- Topic: Private Prisons against crime
- Replies:
**52** - Views:
**15280**

### Private Prisons against crime

I was thinking about the American prison system, about how the prison companies' best interest is to incarcerate as many people as possible while spending as little as possible on each of them. And while normally I'd look for your average bleeding-heart, probably Scandinavian-tested solution to a pr...

- Sat Feb 23, 2013 7:06 pm UTC
- Forum: Mathematics
- Topic: Eigenvalue problem
- Replies:
**2** - Views:
**1049**

### Re: Eigenvalue problem

Sort of homework (I need a variation of Schur's lemma for something), but no one will complain if I just skip that part of the proof, so this is just personal curiosity. But I do see a solution now: Look at fg

^{-1}- z*Id, fg^{-1}has some Eigenvalue z_{0}, set z=z_{0}, done. Thanks.- Sat Feb 23, 2013 4:51 pm UTC
- Forum: Mathematics
- Topic: Eigenvalue problem
- Replies:
**2** - Views:
**1049**

### Eigenvalue problem

Hey everybody, I have a little problem in linear algebra, I'd be much obliged for an answer: Let V be a finite-dimensional C -vector space, f and g automorphisms of V. Can I always find z in C so that f-zg has nonzero kernel? This seems really easy, but I just can't seem to figure it out (or rather,...

- Wed Oct 17, 2012 2:39 pm UTC
- Forum: Mathematics
- Topic: The projective Weil representation of SL_2(Z/nZ)
- Replies:
**1** - Views:
**598**

### The projective Weil representation of SL_2(Z/nZ)

I have a very specific question about this paper (which I will explain here, you don't have to read it to understand my question). I am writing my bachelor thesis on this, and I stumbled over one thing that I just don't understand. What we want is a specific projective representation of SL_2(\ma...

- Tue Feb 28, 2012 1:35 pm UTC
- Forum: Mathematics
- Topic: Funny mathematical terms and statements
- Replies:
**21** - Views:
**7695**

### Funny mathematical terms and statements

While I was reading the Expospeak Gag entry on tvtropes, I realized that modern math has a lot of 'inverse expospeak' statements - statements using plain language that refer to something only a few experts understand, and are nonsensical to everyone else. Sadly, I'm learning mathematics in Germany a...

- Mon Dec 12, 2011 9:48 am UTC
- Forum: Mathematics
- Topic: Some questions about the volume of the n-ball.
- Replies:
**25** - Views:
**6499**

### Re: Some questions about the volume of the n-ball.

I feel like all these handwavy versions are kinda weak guys. There's a much more direct approach. Its called algebra. So again, let B_n(r) = C_n r^n. We need a decent formula for C_n that isn't "presolved" like Hack put in the OP ie a formula for the volume of the unit ball that i...

- Fri Dec 09, 2011 9:28 am UTC
- Forum: Mathematics
- Topic: Some questions about the volume of the n-ball.
- Replies:
**25** - Views:
**6499**

### Re: Some questions about the volume of the n-ball.

Another idea: What's easy to see is that the volume of the n-ball of the ||\cdot||_1 -norm goes to 0, because its volume is \frac{(2r)^n}{n!} (which I think is rather easy to see), and since (I think) the volume of the 2-norm-n-ball behaves roughly like the square root of the 1-norm-n-ball, ...

- Thu Dec 08, 2011 9:52 am UTC
- Forum: Mathematics
- Topic: Some questions about the volume of the n-ball.
- Replies:
**25** - Views:
**6499**

### Some questions about the volume of the n-ball.

We just had the formula for the volume of the n-dimensional ball of radius r, which is B_{2n}(r)=\frac{r^{2n}}{n!}\cdot\pi^n for even numbers and B_{2n+1}(r)=\frac{r^{2n+1}2^{n+1}}{(2n+1)!!}\cdot\pi^n for odd ones (with !! denoting the double factorial, i.e. the product of al...

- Sun Jun 19, 2011 7:59 pm UTC
- Forum: Forum Games
- Topic: Non-Sequitur Showdown.
- Replies:
**4132** - Views:
**482053**

### Re: Non-Sequitur Showdown.

Pleeease, for just one second, suppose that you could choose. Wouldn't it be much nicer to eat cake at night than outside? I mean, what with this being a capitalistic country club?

- Mon Mar 07, 2011 12:39 am UTC
- Forum: The Help Desk
- Topic: [RESOLVED] Abstract classes in Java homework
- Replies:
**2** - Views:
**641**

### Re: Abstract classes in Java homework

Thank you so much! It all makes sense now that I got rid of the constructor.

- Sun Mar 06, 2011 7:37 pm UTC
- Forum: The Help Desk
- Topic: [RESOLVED] Abstract classes in Java homework
- Replies:
**2** - Views:
**641**

### [RESOLVED] Abstract classes in Java homework

Hello dear helpful readers, I am am in the process of learning the stuff of the first semester of CS on my own, using only the script and the homework of this semester. I am using Eclipse. The homework where I'm stuck now is to program a desktop calculator in two steps, programming a GUI and writing...

- Mon Jan 17, 2011 12:47 am UTC
- Forum: Mathematics
- Topic: functions that give cool designs
- Replies:
**56** - Views:
**17202**

### Re: functions that gives cool designs.

While I wouldn't really advise asking a mathematical genius for tips on Algebra homework (unless that's their job), I think it's more or less the duty of someone who is very good and thoroughly enjoys math (or any field) to tell people who ask 'why is this interesting?' It should be their inherent ...

- Sun Jan 16, 2011 11:30 pm UTC
- Forum: Mathematics
- Topic: functions that give cool designs
- Replies:
**56** - Views:
**17202**

### Re: functions that gives cool designs.

I thought you all genius guys would pt some cool functions in here.... but I was wrong.... This is only a side note, but there is something that I learned* about math as I started to think about becoming a real mathematician: Apparently you think that a genius would think like you, and care about t...

- Thu Dec 16, 2010 1:13 pm UTC
- Forum: Mathematics
- Topic: Useless Math
- Replies:
**60** - Views:
**9183**

### Re: Useless Math

What I'm trying to say is that they they (inclusive of irrational and complex numbers just the same as natural numbers) don't exist in the sense that objects exist, but exist as ideas in the minds of people, independent of whatever it is they describe. (to contrast aAristotle, who says that numbers...

- Thu Nov 25, 2010 12:05 am UTC
- Forum: Mathematics
- Topic: Disguised forms of 2
- Replies:
**114** - Views:
**12134**

### Re: Disguised forms of 2

Using Gregory Numbers: \Biggl[{\sin \left(\frac{5}{\sqrt{50}}\left(1+\sum_{i=1}^{\infty}\left(\frac{(2i-1)!!}{(2i)!!}\cdot\frac{1}{(2i-1)50^i}\right)\right)+\frac{2}{\sqrt{325}}\left(1+\sum_{i=1}^{\infty}\left(\frac{(2i-1)!!}{(2i)!!...

- Wed Oct 20, 2010 1:23 pm UTC
- Forum: Mathematics
- Topic: Is there a field of every infinite cardinality?
- Replies:
**6** - Views:
**2026**

### Re: Is there a field of every infinite cardinality?

phr34k wrote:http://en.wikipedia.org/wiki/Surreal_number

that's only a field to some degree, because the Surreals don't range over a set, only a class, so technically, it's not a field.

- Fri Aug 13, 2010 9:41 pm UTC
- Forum: Serious Business
- Topic: A SB Debate Club
- Replies:
**2** - Views:
**1187**

### A SB Debate Club

Disclaimer: I don't know whether this thread belongs here, as it isn't a discussion in the usual style, but rather an open-ended question on how to re-create the SB atmosphere (or parts of it) in RL. I don't know where else a thread like this should go, so I let the mods decide. Since some time I'm...

- Sun Jul 11, 2010 7:00 pm UTC
- Forum: Mathematics
- Topic: Math: Fleeting Thoughts
- Replies:
**383** - Views:
**128084**

### Re: Math: Fleeting Thoughts

@ PM2Ring: Thanks! And you are right that it was Gauss who found the sum over the first 100 integers at the age of six, but: His point was to one-up the legend of Euler's youth and show how you could sum up the first hundred tenth powers in under a minute by hand. That is a different story, and I'm ...

- Sun Jul 11, 2010 6:30 pm UTC
- Forum: Mathematics
- Topic: Math: Fleeting Thoughts
- Replies:
**383** - Views:
**128084**

### Re: Math: Fleeting Thoughts

And yes, it was Gauss, not Euler. Really? I don't have the book at hand right now, but I'm rather certain that it was one of the Bernoullis. We once had a thread about differentiating a function r times where r would be a real number; example: \frac{d^r}{dx^r} x^n = \frac{\Gamma(n+1)}{\Gamm...

- Thu Jul 01, 2010 10:43 pm UTC
- Forum: General
- Topic: Post your boat race.
- Replies:
**20908** - Views:
**2717987**

### Re: Postify your facerity

It's a stupid dayjob, but it pays:

I've got a New Hat!

@micco: Awesome Goggles are Awesome.

**Spoiler:**

I've got a New Hat!

**Spoiler:**

@micco: Awesome Goggles are Awesome.

- Mon May 31, 2010 2:58 pm UTC
- Forum: Mathematics
- Topic: Most interesting mathematician?
- Replies:
**35** - Views:
**4809**

### Re: Most interesting mathematician?

I think you should pay a bit of attention to what you're supposed to be doing; that is, present a mathematician to a high school class, probably in a very limited frame of time. I think that may help narrow it down: ⋅ He should be somewhat well-known. Grothendieck may have led a very inter...

- Fri Apr 09, 2010 10:00 pm UTC
- Forum: The Help Desk
- Topic: TuxGuitar crashed with installation of Ubuntu 9.04 [solved]
- Replies:
**1** - Views:
**500**

### TuxGuitar crashed with installation of Ubuntu 9.04 [solved]

Exactly what it says on the tin in the title. I finally gave in to the tempting "New distribution 'Ubuntu 9.04' is available now" and it even warned me that some packets would be deleted. "Whatever" I thought, installed, and went to try TuxGuitar - which didn't make a sound. I tr...

- Tue Apr 06, 2010 9:21 am UTC
- Forum: Mathematics
- Topic: Pythagorean Tedrahedra
- Replies:
**2** - Views:
**439**

### Pythagorean Tedrahedra

While fooling around with the pythagorean theorem, I stumbled upon an interesting question: Is there a tetrahedron with integer-length edges and three right angles? The tetrahedra can be summed into three forms: one where all right angles meet at one vertex (you could get this one with a single cut ...

- Mon Apr 05, 2010 3:32 pm UTC
- Forum: General
- Topic: Post your boat race.
- Replies:
**20908** - Views:
**2717987**

### Re: Postify your facerity

I was on a mountain trip.

On the top of the mountain:

More are to come...

**Spoiler:**

On the top of the mountain:

**Spoiler:**

More are to come...

- Mon Apr 05, 2010 3:16 pm UTC
- Forum: The Help Desk
- Topic: Internet trouble by country change?
- Replies:
**2** - Views:
**444**

### Internet trouble by country change?

I've just recently moved from Germany to France, and now some things about my web connection don't seem to work properly. While I can access the internet perfectly fine (as you're just noticing), I can't send or accept mails in my mail program (evolution), can't upload stuff on twitter & save ar...

- Sun Mar 28, 2010 11:33 pm UTC
- Forum: General
- Topic: Post your boat race.
- Replies:
**20908** - Views:
**2717987**

### Re: Postify your facerity

Two days ago, I left psychiatry. The workshop for handicapped people, to be precise. (A somewhat misleading name since most people there are mentally ill rather than disabled.) And if you really have to ask: I was there as an civilian service because I refused to do military service. My parents got ...

- Fri Nov 27, 2009 5:32 pm UTC
- Forum: Serious Business
- Topic: "Damsel in Distress" and Sexism
- Replies:
**308** - Views:
**32044**

### Re: "Damsel in Distress" and Sexism

I'd guess not. First, the study would need to be read by (or at least made known and credible to) all those people who make up that market, but even then, the powers that be would need to decide that "treat genders equally" is increasing their profits, and at least in movies and games, th...

- Wed Nov 25, 2009 8:47 pm UTC
- Forum: Serious Business
- Topic: "Damsel in Distress" and Sexism
- Replies:
**308** - Views:
**32044**

### Re: "Damsel in Distress" and Sexism

Generally, if we want to use gender portrayal in media as a knob to get better behavior out of people, we should be aware of how much benefit we get for turning that knob. It could be that even if a movement against "sexist" games gathered enough people to provide market pressure to chang...

- Wed Nov 18, 2009 11:56 am UTC
- Forum: General
- Topic: Slacker aphorisms
- Replies:
**105** - Views:
**8243**

### Re: Slacker aphorisms

"A journey of a 1000 miles" starts with an A.

A journey of a 1000 miles starts with a single lion. (yay qc!)

Speak softly and carry a big wallet, you will get far.

A pet may actually be mightier than a sword...

Don't count your chickens before they're hatched. Count the eggs.

A journey of a 1000 miles starts with a single lion. (yay qc!)

Speak softly and carry a big wallet, you will get far.

A pet may actually be mightier than a sword...

Don't count your chickens before they're hatched. Count the eggs.

- Tue Nov 17, 2009 4:30 pm UTC
- Forum: The Help Desk
- Topic: My Laptop/Linux/Firefox vs. Echochamber/phpBB
- Replies:
**8** - Views:
**1350**

### Re: My Laptop/Linux/Firefox vs. Echochamber/phpBB

Game_boy wrote:This happened to me, and while clearing cookies did not help, deleting cookies.sqlite and cookies.sqlite-journal did. You can find them under your profile folder (maybe under .mozilla in your home directory?).

Thank you fuckloads! There was no file named cookies.sqlite-journal, but whatever.

- Tue Nov 17, 2009 9:43 am UTC
- Forum: General
- Topic: ITT: We make xkcd slightly worse.
- Replies:
**8652** - Views:
**1643492**

### Re: ITT: We make xkcd slightly worse.

chridd wrote:Did you draw that by hand?

Yes, and I got it into my computer by a camera... I fail at technology.

@ Maseiken: I got the idea when I watched so much Daria in a row that I actually started to get morgendorfferian paracusia.

- Mon Nov 16, 2009 5:54 pm UTC
- Forum: General
- Topic: ITT: We make xkcd slightly worse.
- Replies:
**8652** - Views:
**1643492**

- Fri Nov 06, 2009 7:53 pm UTC
- Forum: The Help Desk
- Topic: My Laptop/Linux/Firefox vs. Echochamber/phpBB
- Replies:
**8** - Views:
**1350**

### My Laptop/Linux/Firefox vs. Echochamber/phpBB

I am writing this post from my parents' near-broken laptop, because when I use mine, the fora won't let me in. To be precise, I enter my (definitely correct, I made that double sure) name and password, click on "login", get to see the "you are logged in successfully"-screen, and ...

- Tue Oct 20, 2009 9:09 pm UTC
- Forum: Mathematics
- Topic: Recommend me a good introductory text on Game Theory
- Replies:
**14** - Views:
**1591**

### Re: Recommend me a good introductory text on Game Theory

I'm also interested in combinatorial game theory, and I do happen to want to get Winning Ways at some point, so kudos for that suggestions too. I'll look into that stuff. Just to be sure: Combinatorial Game Theory is about as far from traditional Game Theory as you can get in mathematics while stil...

- Sun Oct 18, 2009 9:07 pm UTC
- Forum: General
- Topic: Undesired traits (you wish to change about yourself)
- Replies:
**63** - Views:
**5673**

### Re: Undesired traits (you wish to change about yourself)

I wish I was better at saying no to people, at being hard with them, less easily frightened by others - and of course, all this only when appropriate. I don't want to laisser faire the others. Relatedly, I would like to be better at resisting authorities, like my fellow civil service colleague.

- Mon Oct 05, 2009 9:01 pm UTC
- Forum: General
- Topic: Post your boat race.
- Replies:
**20908** - Views:
**2717987**

### Re: Postify your facerity

I bought a vest [waistcoat?] today, because it's amazing (obviously). Then I combined it with three different shirts (one at a time, of course. What kind of question is that??). See below for results: White shirt: weste-weiß.jpg Dark red: weste-rot.jpg And black: weste-schwarz.jpg Also, a picture of...

- Fri Oct 02, 2009 4:13 pm UTC
- Forum: General
- Topic: what would you choose as your super power?
- Replies:
**636** - Views:
**68421**

### Re: Super-ish Powers

I'd love to be wicked fast at mental calculation and to have a great short-time memory. I could probably learn the first, but I'd have to learn...

- Wed Sep 30, 2009 6:44 pm UTC
- Forum: General
- Topic: Lucky Ten Thousand (TIL)
- Replies:
**13405** - Views:
**1546188**

### Re: Today I Learned

Today I learned that being angry doesn't, in fact, increase your IQ.

- Sun Sep 27, 2009 9:11 pm UTC
- Forum: General
- Topic: Post your boat race.
- Replies:
**20908** - Views:
**2717987**

### Re: Postify your facerity

I found a picatchu of me on Facebook! fix'd! Also, maycelestia looks great. Moving on to me: Posin' as a muthalovin' goth (i.e. trying my new men's skirt and boots on): goth1.png I have trouble smiling on photographs, see below for reference: goth2.jpg The surrounding doesn't look exactly dark and ...