Massemord - Skogen Kaller Og Vi Svarer

Skogen Kaller Og Vi Svarer (The Forest Calls And We Answer) by (Norwegian) Massemord is a great black metal song. In particular, I like the sampled hymn at the beginning.

very simple linear algebra puzzle

Since I intend to study operations research in my free time, I need to revisit a lot of the linear algebra material I had a better command of a while ago. That is essential to understanding the simplex and related algorithms. In Jim Hefferon's Linear Algebra, there is a really cute puzzle close to the beginning. It's so easy it's almost not worth mentioning, but I still had fun with it for a few minutes. Here it is:

Three truck drivers went into a roadside cafe. One truck driver purchased four sandwiches, a cup of coffee, and ten doughnuts for $8.45. Another driver purchased three sandwiches, a cup of coffee, and seven doughnuts for $6.30. What did the third truck driver pay for a sandwich, a cup of coffee, and a doughnut?

My solution was a bit different from the book's. The first two purchases can be represented as the linear equations and , respectively. They can be reduced to the linear combination . (I never thought of donuts as parameters. I guess I'm in for more surprises when I study topology.)

Anyway, with that knowledge, you can substitute into the equation with the unknown right-hand value (i.e., the cost of the third purchase) and so arrive at . The terms cancel out and so you are left with a constant: two dollars for the third trucker's purchase. Not a bad deal at all, to be honest. Notice that, even with the added constant, there is still a free variable in this system. As such, the menu items can assume infinitely many combinations of prices s.t. they are non-negative and very economical.

lol Doom soundtrack ripped off classic metal songs

OWNT LOL

ridiculous chain letter

After pissing away most of the weekend on Battle for Wesnoth (with a little worthwhile time spent on linear algebra and game theory), I came across a chain letter that was posted on a forum I frequent. The gist of it is that it will be possible to push down the price of gas with a boycott of Shell and Esso. Here's my synopsis

This was sent by a retired Coca Cola executive. It came from one of his engineer buddies who retired from Halliburton. If you are tired of the gas prices going up AND they will continue to rise this summer, take time to read this PLEASE.

The capital letters, anonymous executive and company name-dropping make my bullshit counter begin to click and pop.

Now that the oil companies and the OPEC nations have conditioned us to think that the cost of a gallon of gas is CHEAP at $1.14, we need to take aggressive action to teach them that BUYERS control the marketplace...not sellers.

Unfortunately, though, buyers don't control how much oil is left in the ground. As such, the law of supply and demand must bring up the price of petroleum and its slick rainbow of distillates.

I am sending this note to 30 people. If each of us s end it to at least ten more (30 x 10 = 300) .. and those 300 send it to at least ten more (300 x 10 = 3,000)...and so on, by the time the message reaches the sixth group of people, we will have reached over THREE MILLION consumers. If those three million get excited and pass this on to ten friends each, then 30 million people will have been contacted!

This is basically the logic behind the pyramid scheme. The bullshit counter has pegged.

If you don't understand how we can reach 300 million and all you have to do is send this to 10 people.... Well, let's face it, you just aren't a mathematician. But I am. So trust me on this one.

By the geometric series formula , we have 33,333,330 people for the sixth iteration (not ~300 million as the chain letter author claims).

However, even that is a hopelessly ideal figure. It assumes that each recipient is unique, i.e., no one gets the same letter twice. The summation the author uses also assumes that everyone who receives the letter propagates it. Gullible as I am, I played into the author's hands by bringing it up here. Shame on me. (But no one will see it of course, so moot point.)

I'm not even much of a mathematician as of now, but I'm still a hell of a lot better than whoever first spawned this junk. The arrogance of the author is screaming through my head.

Well, let's face it, you just aren't a mathematician. But I am. So trust me on this one

Well, let's face it, you just aren't a mathematician. But I am. So trust me on this one

Well, let's face it, you just aren't a mathematician. But I am. So trust me on this one

Maybe this guy is an agent for McNeil Consumer Healthcare because I need a damn ibuprofen right now.

This is why comprehensive math education should be mandatory in high schools. Wouldn't want anyone pulling the wool over on you.

I'll bet you didn't think you and I had that much potential, did
you! Acting together we can make a difference.

If this makes sense to
you, please pass this message on THEY LOWER THEIR PRICES TO BELOW THE $1.00
RANGE AND KEEP THEM DOWN. THIS CAN REALLY WORK.

"Acting together ... we can make a difference!" I've never felt so inspired before! Imagine, someone took precious time out of his day to write a chain letter urging everyone not only to indulge in wasteful, short-sighted habits but also to demand that these destructive habits be made as cheap as possible.

It brought a tear to my eye.

abebooks.com

If you didn't know about this great site already, go there. Many used books with very nominal wear and tear. I just ordered Introduction to Operations Research for 4.75 USD, including shipping. The last book I got from one of their hosted dealers had a few red pen marks that didn't obscure the text at all ... it was a steal. On average, a book there costs a little more than a combo meal at Wendy's and is definitely a better investment in the long run. I recommend it to everyone.

why I'd like to specialize in bioinformatics

I was at the local public radio station last Sunday when I met up with Dr. Jack Zilfou, who hosts the Arabic music program then about every other week. He's a biochemist who develops new medicines. If you Google his name, he has actually authored or co-authored a good deal of research cited in other publications. The last time I saw him was when I was in high school and so we caught up. In addition to finding out that he listened to a lot of thrash metal when he was my age, I learned about the growing opportunities in bioinformatics from him.

“Biology easily has 500 years of exciting problems to work on.” ― Donald Knuth, noted 31337 h4x0r

I had heard about this field vaguely before, but didn't pay it much mind. Jack speaks very highly of this frontier in science. Apparently, he depends on bioinformatics specialists to glean useful information from scads of raw biological data generated every day. After he explained the field in some more detail, it sounded pretty interesting. I did some research on it and found it even more appealing after a closer look. The algorithms entailed in bioinformatics appear to deal mainly with discrete areas of mathematics that I really enjoy using.¹ I communicated this interest of mine to the professor in Bioinformatics at Lehigh when I was asking about how I could study this field and he said that there isn't a Bioinformatics degree program per se, but there is a relevant track in the Computer Science department and bade me good luck.

So, double win. Since I'm already a CS major, I don't have to make a 180 degree turn. Maybe 30 degrees. Here's the triple win for the trifecta:



Wow. Without the labels, I would have guessed that was the graph of the velocity of something being shot out of a mass driver. There is a great demand to deal with this glut of new data and, if the median salary figures mean anything, a relative shortage of qualified people. I can definitely see myself getting avenged for middle school and a little less than half of high school. Eat shit, assholes! Of course, if I had a billion dollars tomorrow I would still enter a CS / math career—because I love these two fields with all my heart. However:



And on top of that, the excitement of knowing that people in the next room are using cancer-causing restriction enzymes. Dipset!

The single fail in this situation, albeit not an epic one, is that Perl seems to be really popular in bioinformatics. That makes sense since the field is mainly concerned with crunching assloads of text, and esp. a lot of pattern matching. However, Perl has an ugly object system, no exception handling and can easily make a Linear A tablet look like Curious George. If I use BioPerl in my career, I just hope no one on my team likes writing illegible garbage. Because I've seen that shit and it's not nice.

¹ - I am also busting my ass retracing my steps over all the important theorems I learned in calculus that were taken for granted in school. I'm surprised I understood anything at all after we basically skipped over the very basic idea of infinitesimals. I'm virtually certain discrete math will always be my strongest suit though.

Yellow Magic Orchestra - Key

Yellow Magic Orchestra was one of the most important pioneering electronic music acts along with peers like Kraftwerk, Brian Eno and Jean-Michel Jarre. They were one of the bands instrumental in making electronic music pop music, since it had been previously limited mainly to realization of well-known classical songs and experimental / musique concrète kinds of work.

Here's the YMO song Key, recorded live in 1983.

I like how the song is preceded by a swordfight and then punctuated by a comedy sketch. Electronic music was generally much better in the 70's and 80's when you had to be batshit insane to create it.

haiku for a CS test

I had an exam
It was about assembly
I kicked its dumb ass

proof that S_n is non-abelian for n > 2

In this post, I prove that the symmetric group is non-abelian (snob for: 'not commutative') for .

I'm pretty sure almost every mathematician hates abstract algebra. I could never understand why that is. It's way easier than calculus. I'll admit it's probably not as useful, although it does have uses in physics, chemistry, cryptography and maybe a few other fields. In any case, I feel abstract algebra is one of the best ways to learn how to write proofs, which is why I like it so much.

Anyway, on to the proof.

Consider the transpositions in for , which I'll call , and , which I'll call . Because and , is non-abelian for . QED

That was very short. It's a result you can be pleased with. When I first wrote my proof for this problem, it was much longer because I defined and . These functions were two I picked out at random which I didn't think would commute. Incidentally, the proof using them is very cute. Because my own and are defined for any value of , you'll notice that and . As such, is obviously abelian for . It's easy and fun to see how becomes non-abelian in this case. However, that proof requires two tedious proof-by-induction lemmas for and and so I have opted instead for the shorter version someone recommended to me, even if it isn't as cute.

There is an important lesson to take away from this story. To paraphrase Charles Hoare: "There are two ways of constructing proofs: one way is to make them so simple that there are obviously no deficiencies; the other way is to make them so complicated that there are no obvious deficiencies." As with everything else in nature, the better, plainer choice is usually hard in practice. Think ahead.

(rendering courtesy of servalx02)

classes next semester

So in the fall I'm taking 19 fucking credits worth of classes to make up for my horrible 14-credit pace of the past three semesters. I kind of look forward to the challenge because at the current rate it's boring the hell out of me. Namely, I (tentatively) have Data Structures & Algorithms, Calc III, Physics for Science and Engineering I (1337), Macroeconomics and Ethics & Moral Problems. On top of that, I have Introduction to Psychology (fuck that) as a web class in the summer, just to round off that two year degree so I can get the hell out of here and start attending Lehigh University.

Due to a scheduling conflict, I have no choice but to take Calc III with Ken Krauss, rather than Alex Rolón. Granted, Rolón's classes are pretty difficult, but he challenges us to think hard about what we do and is overall a better teacher than Krauss. Hopefully, the nearly unanimous disapproval I've heard of his classes is at least part bullshit, because I have Data Structures & Algorithms with him as well. The only other class I've taken with Krauss was Comp Sci I and my brain was in power-saving mode for most of the time. Sure, I got an A, but that's only because I had already seen almost every damn thing he put up on the board. I'm not sure I can put up with him for seven hours a week.

Man, I think I would probably already have an associate's degree if it weren't for the all the bullshit electives I've had to take. Of the six classes I'm going to take in the summer and fall, only three are directly related to the computer science / math track. I can't believe Macroeconomics is a 'Western Culture elective' and that I have to take either it or some other even worse class. If that's true, why can't Calc III be a Western culture elective? Newton (England) and Leibniz (Germany) came up with it in its modern form, right? Every country has macroeconomic affairs, and economics has nothing to do with 'culture', at least from an academic perspective. Even so, even Macroeconomics is not as worthless and irrelevant to my major as something like Ethics & Moral Problems. Like I've said before, 'ethics' is a fictional abstraction. I'm not interested in ethics. Can that shit so I can take cool classes.

Come what may, I will continue to kick ass next semester. Dags för strid!