Need help with category-theory-programmers?
Click the “chat” button below for chat support from the developer who created it, or find similar developers for support.

About the developer

465 Stars 37 Forks MIT License 216 Commits 2 Opened issues


Category theory in the context of (functional) programming

Services available


Need anything else?

Contributors list

Notes on Category Theory and Haskell

The notes can be found here: - pdf - epub (work in progress, missing diagrams and theorems)

This document contains notes on category theory in the context of (functional) programming. Originally they were lecture notes for a seminar hosted at Centrum Wiskunde & Informatica, the national research centre for mathematics and computer science in the Netherlands. The main reason for compiling these notes is to provide a way to gain familiarity with concepts of category theory (and other branches of mathematics) that apply in a broad sense to the field of functional programming.

Although the main focus is on the mathematics, examples are given in Haskell to illustrate how to apply the concepts. In some places, examples are given in other languages as well (such as Python and C++). The topics discussed include:

  • Categories
  • Types as a category
  • Products
  • Yoneda
  • Closed Cartesian categories
  • Adjunctions
  • Monads
  • F-algebras and recursion
  • Comonads
  • Lenses

Generating the document

The notes are written in Markdown, and

is used to generate the document. Running
inside the
directory should result in an (updated) pdf, granted that
and a LaTeX environment are installed.


GitHub can be used for any issues (typos, inaccuracies, ...). Pull requests with fixes or additional material are also very welcome.

We use cookies. If you continue to browse the site, you agree to the use of cookies. For more information on our use of cookies please see our Privacy Policy.