Here’s a little challenge to try before the presentation on October 29th. For those of you who have studied category theory, it will be very simple, but it should be more fun for the rest of you. All you need to solve the challenge is your mind, though a pencil and paper may help.
During my presentation I will give a whiteboard overview of introductory category theory as applied to finite sets. I will then present the Haskell code that I wrote, along with the solution to the challenge problem.1
How many idempotent endomaps exist for any finite set of a given size?
In not-so-mathematical terms, find the number of functions from a given finite set to itself where
f(x) == f(f(x)). Your answer should be an equation with the size of the finite set as the parameter.
If you have the time to watch them, the CUFP 2009 videos have also now been posted.
I personally recommend Conal Eliot’s Beautiful Differentiation talk. It was truly beautiful, and had I had someone like this to teach me first year calculus, I probably would have a degree today.
This month, I’ll be giving a report on what went on at the 2009 International Conference on Functional Programming, which I attended around the beginning of this month. If there’s anything from the proceedings that looks especially interesting to you, drop me an e-mail and I’ll try to give it some extra attention.
If you have a look at the program page for Commercial Users of Functional Programming 2009 you’ll find now that, as well as the abstracts, the slides for the talks have been made available. The videos for both these and other ICFP presentations are probably about a month away, according to Jim Grundy of the ACM.
Since I’ve had a couple of requests, I’ve just posted the slides for both my ICFP 2009 presentation, Haskell in the Real World, and my Haskell Implementor’s Workshop presentation, My Dream GHC Environment.
Both presentations were videotaped, and the ICFP one, at least, is supposed to be available soon (perhaps on Google videos). The videos will no doubt be a lot more informative than my slides,
How he found it I’m not sure, since ICFP Proceedings are not exactly as popular as Slashdot, and nor is my rather dry, academic writing style in this paper as anywhere near as exciting as Yaron Minsky’s Caml Trading presentation. So I’m especially enjoying the love.
I always knew Haskell would bring me fame and (soon, I hope) fortune.