My Favorite Strange Number: Ω (classic repost)

I’m away on vacation this week, taking my kids to Disney World. Since I’m not likely to
have time to write while I’m away, I’m taking the opportunity to re-run an old classic series
of posts on numbers, which were first posted in the summer of 2006. These posts are mildly
revised.

Ω is my own personal favorite transcendental number. Ω isn’t really a specific number, but rather a family of related numbers with bizarre properties. It’s the one real transcendental number that I know of that comes from the theory of computation, that is important, and that expresses meaningful fundamental mathematical properties. It’s also deeply non-computable; meaning that not only is it non-computable, but even computing meta-information about it is non-computable. And yet, it’s almost computable. It’s just all around awfully cool.

Continue reading My Favorite Strange Number: Ω (classic repost)

Continued Fractions (classic repost)

I’m away on vacation this week, taking my kids to Disney World. Since I’m not likely to have time to write while I’m away, I’m taking the opportunity to re-run an old classic series of posts on numbers, which were first posted in the summer of 2006. These posts are mildly revised.

One of the annoying things about how we write numbers is the fact that we generally write things one of two ways: as fractions, or as decimals.

You might want to ask, “Why is that annoying?” (And in fact, that’s what I want you to ask, or else there’s no point in my writing the rest of this!)

It’s annoying because both fractions and decimals can both only describe rational numbers – that is, numbers that are a perfect ratio of two integers. The problem with that is that most numbers aren’t rational. Our standard notations are incapable of representing the precise values of the overwhelming majority of numbers!

But it’s even more annoying than that: if you use decimals, then there are lots of rational numbers that you can’t represent exactly (i.e., 1/3); and if you use fractions, then it’s hard to express the idea that the fraction isn’t exact. (How do you write π as a fraction? 22/7 is a standard fractional approximation, but how do you say π, which is almost 22/7?)

So what do we do?

Continue reading Continued Fractions (classic repost)

Idiotic Gitt: AiG and Bad Information Theory (classic repost)

I’m away on vacation this week, taking my kids to Disney World. Since I’m not likely to have time to write while I’m away, I’m taking the opportunity to re-run some old classic posts which were first posted in the summer of 2006. These posts are mildly revised.

Back when I first wrote this post, I was taking a break from some puzzling debugging.
Since I was already a bit frazzled, and I felt like I needed some comic relief, I decided to
hit one of my favorite comedy sites, Answers in Genesis. I can pretty much always find
something sufficiently stupid to amuse me on their site. On that fateful day, I came across a
gem called Information, science and biology”, by the all too appropriately named
“Werner Gitt”. It’s yet another attempt by a creationist twit to find some way to use
information theory to prove that life must have been created by god.

This article really interested me in the bad-math way, because I’m a big fan of information theory. I don’t pretend to be anything close to an expert in it, but I’m
fascinated by it. I’ve read several texts on it, taken one course in grad school, and had the incredible good fortune of getting to know Greg Chaitin, one of the co-inventors of algorithmic information theory. Basically, it’s safe to say that I know enough about
information theory to get myself into trouble.

Unlike admission above, it looks like the Gitt hasn’t actually read any real
information theory much less understood it. All that he’s done is heard Dembski presenting
one of his wretched mischaracterizations, and then regurgitated and expanded upon them.
Dembski was bad enough; building on an incomplete understanding of Dembski’s misrepresentations, misunderstandings, and outright and errors produces a result
that is just astonishingly ridiculous. It’s actually a splendid example of my mantra on this blog: “the worst math is no math“; the entire article pretends to be doing math – but it’s actual mathematical content is nil. Still, to the day of this repost, I continue
to see references to this article as “Gitt’s math” or “Gitt’s proof”.

Continue reading Idiotic Gitt: AiG and Bad Information Theory (classic repost)

e: the Unnatural Natural Number (classic repost)

I’m away on vacation this week, taking my kids to Disney World. Since I’m not likely to have time to write while I’m away, I’m taking the opportunity to re-run an old classic series of posts on numbers, which were first posted in the summer of 2006. These posts are mildly revised.

Anyway. Todays number is e, aka Euler’s constant, aka the natural log base. e is a very odd number, but very fundamental. It shows up constantly, in all sorts of strange places where you wouldn’t expect it.

Continue reading e: the Unnatural Natural Number (classic repost)

Roman Numerals and Arithmetic

. I’m away on vacation this week, taking my kids to Disney World. Since I’m not likely to
have time to write while I’m away, I’m taking the opportunity to re-run an old classic series
of posts on numbers, which were first posted in the summer of 2006. These posts are mildly
revised.

I’ve always been perplexed by roman numerals.

First of all, they’re just weird. Why would anyone come up with something so strange as a
way of writing numbers?

And second, given that they’re so damned weird, hard to read, hard to work with, why do
we still use them for so many things today?

Continue reading Roman Numerals and Arithmetic

i: the Imaginary Number (classic repost)

I’m away on vacation this week, taking my kids to Disney World. Since I’m not likely to have time to write while I’m away, I’m taking the opportunity to re-run an old classic series of posts on numbers, which were first posted in the summer of 2006. These posts are mildly revised.

After the amazing response to my post about zero, I thought I’d do one about something that’s fascinated me for a long time: the number i, the square root of -1. Where’d this strange thing come from? Is it real (not in the sense of real numbers, but in the sense of representing something real and meaningful)? What’s it good for?

Continue reading i: the Imaginary Number (classic repost)

Zero (classic repost)

This post originally came about as a result of the first time I participated in a DonorsChoose fundraiser. I offered to write articles on requested topics for anyone who donated above a certain amount. I only had one taker, who asked for an article about zero. I was initially a bit taken aback by the request – what could I write about zero? This article which resulted from it ended up turning out to be one of the all-time reader-favorites for this blog!

Continue reading Zero (classic repost)