Charlotte AtenWhile teaching a course on algebraic theories last semester I mentioned at some point that the familiar bicomplete categories Top and Poset were not algebraic, but were topological. A student asked about this later on and I found that the #Wikipedia page on «topological category» pointed to categories enriched in Top, not categories with a forgetful functor to Set which is topological. While I have lost a lot of faith in Wikipedia recently, I am pleased to report that https://en.wikipedia.org/wiki/Topological_category is now a disambiguation page.
Jencel PanicCool writeup presenting universal properties as natural isomorphisms:
Understanding Universal Property and Universal Element (from Category Theory in Context, Riehl)
I'm trying to understand universal Property and universal element as stated in Category Theory in Context. The book states So from what I understand, since $C(c, -)$ is representable, there exists
Random #categoryTheory fact: The Yoneda lemma can be seen (among 1000 other things) as a generalization of the definition that a set contains no structure, other than its elements.
Tom de JongDoes anybody know how to typeset pullback/pushout corners in typst/fletcher?
The code provided at https://github.com/Jollywatt/typst-fletcher/issues/50#issuecomment-2851846670 does not quite work for me and even when it does, it requires experimenting with degrees which is bad.
[Update] I added my own workaround as a reply to the GitHub issue.
N-gated Hacker News🤦♂️ Ah yes, because what every overworked developer dreams of is an IDE that speaks the fluent gibberish of category theory. 🚀 Just sprinkle some "categorical magic dust" on your databases and watch them transform (or maybe just disappear into the void). Call Conexus AI for a personalized headache consultation. 📞🤯
https://categoricaldata.net/ #overworkeddevelopers #categorytheory #IDEs #ConexusAI #techhumor #HackerNews #ngated
https://categoricaldata.net/ #overworkeddevelopers #categorytheory #IDEs #ConexusAI #techhumor #HackerNews #ngated
marcoshApplicatives allow performing static analysis, while monads do not. But what does it mean in practice? Why is it so? And what kind of static analysis is this referring to? And what happens if we use categories instead of monads?
These are some of the questions I’m trying to provide an answer to in my latest blog post:
https://marcosh.github.io/post/2026/05/21/homomorphic-static-analysis.html
📚🤖 "Behold! The magnum opus on #Rust and Category Theory that's sure to revolutionize your understanding of... nothing. 😂 Dive into this unfinished 'draft' if you're into the esoteric joy of turning simple concepts into convoluted gibberish. 🚀👨💻✨"
https://hghalebi.github.io/category_theory_transformer_rs/ #CategoryTheory #EsotericHumor #TechHumor #Programming #HackerNews #ngated
https://hghalebi.github.io/category_theory_transformer_rs/ #CategoryTheory #EsotericHumor #TechHumor #Programming #HackerNews #ngated
Hacker NewsBuilding ML framework with Rust and Category Theory
https://hghalebi.github.io/category_theory_transformer_rs/
#HackerNews #ML #Rust #CategoryTheory #Framework #Development
Stefano Volpe 
Towards a Higher-Order Bialgebraic Denotational Semantics by Sergey Goncharov, @mperessotti, @stelios, Henning Urbat, and me has been (unconditionally) accepted at ICFP'26! Abstract below 
#icfp #functionalProgramming #programmingLanguages #semantics #coalgebra #categoryTheory
#icfp #functionalProgramming #programmingLanguages #semantics #coalgebra #categoryTheory
New blog post!
https://marcosh.github.io/post/2026/05/08/categorical-transformers.html
where I start to explore what #haskell could be if we wanted to use #categories instead of #monads
