goodmath

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July 4, 2008
Once again, there's a silly article somewhere, and everyone hammers me with requests to write about it. It's frankly flattering that people see this sort of nonsense, and immediately think of asking me about it - you folks are going to give me a swelled head! The article in question is a recent…
June 30, 2008
I'm a bit late to the party on this, but I couldn't resist saying something. A rather obnoxious twit by the name of Richard Vedder has set up a front-group called "The Center for College Affordability and Productivity". The goal of this group is purportedly to apply market-based mechanisms to the…
June 27, 2008
This is an interesting recipe, in a very unusual vein for me. Homemade tonic water. I hate tonic water. I really despise the stuff. But like a lot of people, I have some strange twitchy muscle ticks, in my legs and my eyelids. A few years ago, I was talking to my opthamologist about the eyelid…
June 27, 2008
I haven't done a FRT in a while. Mogwai, "Kids Will be Skeletons": a typical Mogwai track; brilliant post-rock. The Redneck Manifesto, "Bring Your Own Blood: more post-rock in the same general vein as Mogwai. This one is a bit up-tempo, with a very cool rythym. Gogol Bordello, "Dub the…
June 24, 2008
So I hear, via the Panda's Thumb, that Uncommon Descent has a new poster. And he's off to a rollicking good start, with a post explaining why Christians who accept the fact of evolution are incoherent and deluded. (As usual, I don't link to UD, due to their rampant dishonesty in silently altering…
June 23, 2008
UPDATE(9/1): In a move that, frankly, astonished me, the author of the piece that I mocked in this post has withdrawn the article, because he's recognized its errors. And he didn't just withdraw it - he came back to this blog to explain the withdrawal. I've never seen a fundamentalist writer admit…
June 13, 2008
Via several blogs, including the normally wonderfulMaking Light comes a link to an obnoxious Reuters' story that once again demonstrates just how scientifically and mathematically illiterate reporters are. We have yet another company basically claiming to have invented a perpetual motion machine…
June 12, 2008
A reader sent me a really wonderfully wacko link. It's a fundamentalist islamic site, which tries to use relativity to argue for the divinity of the Koran. It's remarkably silly. (I also recently got a link to something similar, but from a Jewish perspective - claiming that the Torah disproves…
June 10, 2008
So, I've finally had some time to get back to the linear programming followup. You might want to go back and look at the earlier post to remember what I was talking about. The basic idea is that we've got a system we'd like to optimize. The constraints of the system are defined by a set of linear…
June 4, 2008
This is the second part of my series trying to answer peoples questions about how mortgages work, and what went wrong. In the first part, I described what a mortgage is, and how it works. In this part, I'm going to describe the mortgage system - that is, the collection of people and organizations…
May 30, 2008
One thing that I've been getting a lot of requests about is the ongoing mortgage mess in the US. I wrote a bit about it a while ago, explaining what was going on. But since then, I've gotten a lot of people asking me to explain various things about how mortgages work, and what kinds of trouble…
May 28, 2008
During my Haskell tutorial, I used balanced binary search trees as an example. I've had people write to me asking me to write about that in a non-functional programming post, because the Haskell one got too tied up in how to do things without assignments, and with tail recursion. Binary search…
May 27, 2008
As you've hopefully all heard by now, the Mars Phoenix lander made a perfect landing over the weekend, and is already returning images. NASA managed to not only achieve a perfect landing, but to use Mars reconnaissance orbiter to catch a picture of the Phoenix descending with parachutes deployed…
May 20, 2008
A bunch of people have been mailing me links to an article from USA today about schools and grading systems. I think that most of the people who've been sending it to me want me to flame it as a silly idea; but I'm not going to do that. Instead, I'm going to focus on an issue of presentation. What…
May 13, 2008
This has been mentioned elsewhere - like on the Machinist blog on Salon (where I first saw it) - but I can't resist saying something about it myself. And I'll also chip in a little bit of originality, by also criticizing some of the people that I've seen criticizing it. The story is, there's a…
May 7, 2008
In my last post on game theory, I said that you could find an optimal probabilistic grand strategy for any two-player, simultaneous move, zero-sum game. It's done through something called linear programming. But linear programming is useful for a whole lot more than just game theory. Linear…
May 6, 2008
One of the most common sleazy tricks used by various sorts of denialists comes back to statistics - invalid and deceptive sampling methods. In fact, the very first real post on the original version of this blog was a shredding of a paper by Mark and David Geier that did this. Proper statistical…
May 5, 2008
The games that we've looked at so far are the simplest case of basic games. In these games, we've got a payoff matrix, and both players can see the whole matrix - the players have equal information, and nothing is secret. The players move simultaneously - so neither player can wait to see what his…
May 1, 2008
Pardon me, while I go off on a rant. Since I came to work for Google, I have a pretty long commute. Most of the time, I don't really mind it. It's all by train - first commuter rail from home into the city, and then subway from the terminal to my office. Commuting by train is not bad at all - you…
April 30, 2008
I was recently fortunate enough to get a review copy of Cory Doctorow's new book, Little Brother">"Little Brother". I've never read Doctorow before, but the book was edited by Patrick Neilsen Hayden, who I think is the best editor in the business, and Patrick says that this book is one of the…
April 29, 2008
Last post, I described the basic idea of the binary heap data structure. But I didn't talk about how to implement it - and there's a very cool way of implementing it - optimally space efficient, very fast, and with respectable cache locality for moderate sized datasets. The idea is to use a…
April 28, 2008
One of the most neglected data structures in the CS repertoire is the heap. Unfortunately, the jargon is overloaded, so "heap" can mean two different things - but there is a connection, which I'll explain in a little while. In many programming languages, when you can dynamically create objects in…
April 25, 2008
Last time I wrote about Game Theory, I explained the basic idea of zero sum games. In their simplest form, a game can be described by a payoff matrix,where each dimension of the matrix is the set of strategies which can be selected by one player, and each entry in the matrix describes the payoffs…
April 16, 2008
You might have heard the story that's been going round about the asteroid Apophis. This is an asteroid that was, briefly, considered by NASA to be a collision risk with earth. But after more observations to gather enough data to compute its orbit more precisely, the result was that it's not a…
April 14, 2008
I've been getting mail all day asking me to explain something that appeared in today's XKCD comic. Yes, I've been reduced to explaining geek comics to my readers. I suppose that there are worse fates. I just can't think of any. :-) But seriously, I'm a huge XKCD fan, and I don't mind explaining…
April 14, 2008
Like the rest of the skeptical blogosphere, I've been watching the uproar around Ben Stein's new movie with a lot of amusement, but also with a lot of disgust. There's one thing that I feel compelled to comment on that I think has, for some reason, not been addressed nearly enough. As I've…
April 14, 2008
I'd like to start with a quick apology. Sorry that both the abstract algebra and the new game theory posts have been moving so slowly. I've been a bit overwhelmed lately with things that need doing right away, and by the time I'm done with all that, I'm too tired to write anything that requires a…
April 9, 2008
The first key concept in probability is called a random variable. Random variables are a key concept - but since they're a key concept of the frequentist school, they are alas, one of the things that bring out more of the Bayesian wars. But the idea of the random variable, and its key position in…
April 7, 2008
To understand a lot of statistical ideas, you need to know about probability. The two fields are inextricably entwined: sampled statistics works because of probabilistic properties of populations. I approach writing about probability with no small amount of trepidation. For some reason that I've…
April 5, 2008
I just had to promote this to the top level of the blog. If you remember, way back in December, I posted something about Sal Cordova's new blog. (As an interesting sidenote, Sal started his blog after supposedly resigning from Uncommon Descent, claiming that he was returning to school, and that…