Tag Archives: subtraction

Subtracting natural numbers: types and usability

For several years now I have been working on a functional teaching language for discrete mathematics, called Disco. It has a strong static type system, subtyping, equirecursive algebraic types, built-in property-based testing, and mathematically-inspired syntax. If you want to know … Continue reading

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What’s the Difference? video and slides

At ICFP in St. Louis I presented my paper with Kenny Foner, What’s the Difference? A Functional Pearl on Subtracting Bijections. Many people seemed to enjoy the talk and we got lots of great feedback afterwards. We will probably write up … Continue reading

Posted in combinatorics, haskell, writing | Tagged , , , , , , | 2 Comments

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

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Species subtraction made simple

> {-# OPTIONS_GHC -fno-warn-missing-methods #-} > module Virtual where > > import Control.Applicative > import Test.QuickCheck Yesterday on #haskell, augur asked me to explain how subtraction works for combinatorial species. (For an introduction to species, see my paper from the … Continue reading

Posted in combinatorics, haskell | Tagged , , , , , , , | 15 Comments