# Why oh why Y?

So in the last few posts, I’ve been building up the bits and pieces that turn lambda calculus into a useful system. We’ve got numbers, booleans, and choice operators. The only thing we’re lacking is some kind of repetition or iteration. In lambda calculus, all iteration is done by recursion. In fact, recursion is a…

# The Genius of Alonzo Church (rerun)

I’m on vacation this week, so I’m posting reruns of some of the better articles from when Goodmath/Badmath was on Blogger. Todays is a combination of two short posts on numbers and control booleans in λ calculus. So, now, time to move on to doing interesting stuff with lambda calculus. To start with, for convenience,…

# Berlinski responds: A Digested Debate

I thought that for a followup to yesterday’s repost of my takedown of Berlinksi, that today I’d show you a digested version of the debate that ensued when Berlinksi showed up to defend himself. You can see the original post and the subsequent discussion here. It’s interesting, because it demonstrates the kinds of debating tactics…

# A Lambda Calculus rerun

I’m on vacation this week, so I’m recycling some posts that I thought were particularly interesting to give you something to read. ———— In computer science, especially in the field of programming languages, we tend to use one particular calculus a lot: the Lambda calculus. Lambda calculus is also extensively used by logicians studying the…

I’m away on vacation this week, so this is a repost of one of early GM/BM entries when it was on Blogger. As usual, I’ve revised it slightly. Berlinksi actually showed up and responded; a digest of the discussion back and forth is scheduled to appear here later this week. ——————————- In my never-ending quest…

# Vacation Time

I’m leaving on vacation today. I’ll be away for a week, with intermittent internet access. And even when I have access, I doubt I’ll have much time to do blog-related stuff. I’ve scheduled a bunch of reposts of some of my favorite posts from the early days of _Goodmath, Badmath_ back when it lived on…

# Poincare, Perelman, and Prizes

About 10 days ago, I wrote about [Grigory Perelman and his proof of the Poincare conjecture][poincare]. This is a quick followup. There’s a more detailed story over on [Seed][seed]. The Fields medal was supposed to be presented this past week, and they planned on presenting it to Perelman. He turned it down. He refused to…

# Working in Industry vs Working in Academia

Over the six months tÃ¥hat I’ve been writing this blog, I’ve gotten a bunch of email from people asking about what it’s like working as a researcher in industry vs working in academia. It’s a good question, one which I’ve spent a lot of time thinking about. So I thought it was worth turning into…

# Ultimate Spaghetti Coding with Linguine

Todays dose of programming pathology is a monstrosity called *Linguine*. Linguine is a language that (obviously) carries spaghetti code to an extreme. You can see the [language specification][linguine-spec], or download an [implementation with examples][linguine-impl]. It’s really a remarkably simple language. There are only 10 commands, including input and output: 1. “`x=y`”: assign the value of…

# Topological Spaces

Yesterday, I introduced the idea of a *metric space*, and then used it to define *open* and *closed* sets in the space. (And of course, being a bozo, I managed to include a typo that made the definition of open sets equivalent to the definition of closed sets. It’s been corrected, but if you’re not…