Assistant Professor of Computer Science at Hendrix College. Functional programmer, mathematician, teacher, pianist, follower of Jesus.

## The Typeclassopedia is now up-to-date

The title pretty much says it all: I have finally finished (I hope) updating the Typeclassopedia to reflect various recent changes to the language and standard libraries (such as the AMP and BBP/FTP). Along the way I also added more … Continue reading

Posted in haskell, writing | Tagged , , , , | 9 Comments

## Algorithms lecture notes and assignments

I just finished teaching our algorithms course for the second time. The first time around, last spring, I was always scrambling at the last minute to prepare for class, make new assignments, and so on (although I did have some … Continue reading

## Submit to the Workshop on Type-Driven Development!

This year I am the co-chair (with Sam Lindley) of the Workshop on Type-Driven Development, affectionately known as TyDe1. The workshop will be co-located with ICFP in Oxford, and is devoted to the use of “static type information…used effectively in … Continue reading

Posted in meta | Tagged , , , | 3 Comments

## Deep work and email habits: a followup

About six months ago I wrote a post about some new work habits I adopted, inspired by Cal Newport’s blog and by his book, Deep Work. First, I began scheduling blocks of “deep work” time during the week, when I … Continue reading

## Signed sets and ballots and naturality

This is blog post #3 in a series on signed sets and ballots (the previous posts are here and here). Naturality, isomorphism, and equipotence When are two species isomorphic? Since species are, by definition, functors , the obvious answer is … Continue reading

Posted in combinatorics, math, species | | 2 Comments

## Signed sets and ballots, part 2

Recall, from my previous post, that our goal is to find a combinatorial proof showing the correspondence between signed sets and signed ballots, where a signed set is just a set of elements, considered positive or negative according to the … Continue reading

Posted in combinatorics, math, species | | 1 Comment

## Signed sets and ballots, part 1

The other day, Anders Claesson wrote a very nice blog post explaining a more combinatorial way to understand multiplicative inverses of virtual species (as opposed to the rather algebraic way I explained it in my previous post). In the middle … Continue reading

Posted in combinatorics, math, species | | 2 Comments