Category Archives: writing

New ICFP functional pearl on subtracting bijections

Kenny Foner and I have a paper accepted to ICFP on subtracting bijections. Here’s the basic problem: suppose you have a bijection between two sum types, , and another bijection . Of course and must have the same size, but … Continue reading

Posted in combinatorics, haskell, writing | Tagged , , , , , | 5 Comments

A (work in progress) translation of Joyal’s original paper on species

tl;dr: I’m working on an English translation, with additional commentary, of Joyal’s 1981 paper introducing the concept of combinatorial species. Collaboration and feedback welcome! Back when I was writing my PhD thesis on combinatorial species, I was aware that André … Continue reading

Posted in combinatorics, projects, species, writing | Tagged , , , , , , | 5 Comments

Off the Beaten Track: Explaining Type Errors

Last week I gave a talk at Off the Beaten Track 2018 about something that Richard Eisenberg, Harley Eades and I have been thinking about recently: namely, how to generate good interactive error explanations for programmers, especially for type errors. … Continue reading

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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

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New Haskell Symposium paper on “twisted functors”

Satvik Chauhan, Piyush Kurur and I have a new paper which will appear at the 2016 Haskell Symposium in Japan: How to Twist Pointers without Breaking Them Although pointer manipulations are used as a primary motivating example, at heart the … Continue reading

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Polynomial Functors Constrained by Regular Expressions

I’ve now finished revising the paper that Dan Piponi and I had accepted to MPC 2015; you can find a PDF here: Polynomial Functors Constrained by Regular Expressions Here’s the 2-minute version: certain operations or restrictions on functors can be … Continue reading

Posted in math, writing | Tagged , , , , , , | 6 Comments

Readers wanted!

tl;dr: Read a draft of my thesis and send me your feedback by September 9! Over the past year I’ve had several people say things along the lines of, “let me know if you want me to read through your … Continue reading

Posted in category theory, combinatorics, diagrams, grad school, math, species, writing | Tagged , , , , | 15 Comments