# \#category
**URL:** https://racket.discourse.group/tag/category/110.md
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## [Category Theory in Programming](https://racket.discourse.group/t/category-theory-in-programming/3375)
**Author:** [@NoahStoryM](https://racket.discourse.group/u/NoahStoryM)\
**Replies:** 3\
**Last updated:** [December 3, 2024, 2:47am UTC](https://racket.discourse.group/t/category-theory-in-programming/3375 "2024-12-03T02:47:15Z")
The full tutorial is here CTP. In this tutorial, I explore the applications of category theory in programming, using Racket to represent abstract mathematical concepts. The completed sections introduce categories, funct…
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## [Functor, Natural tranformation, and Monad in Racket](https://racket.discourse.group/t/functor-natural-tranformation-and-monad-in-racket/1930)
**Author:** [@NoahStoryM](https://racket.discourse.group/u/NoahStoryM)\
**Replies:** 14\
**Last updated:** [August 4, 2023, 6:06am UTC](https://racket.discourse.group/t/functor-natural-tranformation-and-monad-in-racket/1930 "2023-08-04T06:06:21Z")
\#lang racket ;; Functor F : (-\> (-\> A B) (-\> (F A) (F B))) ;; f : (-\> A B) ;; g : (-\> B C) #;(== (compose (F g) (F f)) (F (compose g f))) ;; Natural transformation α F-\>G : (-\> (-\> (F A) (F B)) (-\> (F A) (G B))) …
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## [Construct monad in \`sicp-pict\`?](https://racket.discourse.group/t/construct-monad-in-sicp-pict/985)
**Author:** [@NoahStoryM](https://racket.discourse.group/u/NoahStoryM)\
**Replies:** 5\
**Last updated:** [May 21, 2022, 10:00pm UTC](https://racket.discourse.group/t/construct-monad-in-sicp-pict/985 "2022-05-21T22:00:06Z")
In the current sicp-pict, we treat a picture as a painter, which is a procedure that takes a frame and then draws the picture to a bitmap (so we don't care about its return value, any type is ok). I tried to define a pr…