Author Archives: Brent

About Brent

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

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 | Tagged , , , , , , , | 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 | Tagged , , , , , , | 2 Comments

Virtual species suffice

Over six years ago, I wrote a post explaining how virtual species are defined. Ever since then (time flies!) I’ve been meaning to write a follow-up post explaining a bit more about virtual species and how they actually suffice to … Continue reading

Posted in combinatorics | Tagged , | 23 Comments

Advent of code #16 solution: an algebra of bitstrings

I had fun this past December solving Advent of Code problems in Haskell. I was particularly proud of my solution to one particular problem involving generating and processing large bitstrings, which I’d like to share here. I think it really … Continue reading

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My new programming languages course

tl;dr: my new PL course is now finished, and all the course materials are freely available. Working through all the exercises should be a great option for anyone wishing to learn some basics of programming language design and implementation. Last … Continue reading

Posted in teaching | Tagged , , , | 9 Comments

MonadRandom 0.5 released

I’m happy to announce the release of MonadRandom-0.5, a package which provides a convenient monadic interface for random number generation in the style of transformers and mtl: a Rand monad (essentially a state monad that threads through a generator), a … Continue reading

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MonadRandom 0.5 and mwc-random: feedback wanted

Since 2013 or so I have been the maintainer of the MonadRandom package, which provides an mtl-style type class for monads with support for generation of pseudorandom values, along with a concrete random monad transformer RandT. As of this writing … Continue reading

Posted in haskell, projects | Tagged , | 9 Comments