#categorytheory — Public Fediverse posts

While 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.

#math #mathematics #topology #algebra #CategoryTheory

While 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.

#math #mathematics #topology #algebra #CategoryTheory

Cool writeup presenting universal properties as natural isomorphisms:

https://math.stackexchange.com/questions/3688510/understanding-universal-property-and-universal-element-from-category-theory-in

#categoryTheory

Cool writeup presenting universal properties as natural isomorphisms:

https://math.stackexchange.com/questions/3688510/understanding-universal-property-and-universal-element-from-category-theory-in

#categoryTheory

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.

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.

Does 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.

#typst #typesetting #categorytheory

Does 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.

#typst #typesetting #categorytheory

🤦‍♂️ 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

🤦‍♂️ 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

🤦‍♂️ 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

🤦‍♂️ 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

🤦‍♂️ 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

📚🤖 "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

📚🤖 "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

Building ML framework with Rust and Category Theory

https://hghalebi.github.io/category_theory_transformer_rs/

#HackerNews #ML #Rust #CategoryTheory #Framework #Development

Building ML framework with Rust and Category Theory

https://hghalebi.github.io/category_theory_transformer_rs/

#HackerNews #ML #Rust #CategoryTheory #Framework #Development

Towards a Higher-Order Bialgebraic Denotational Semantics by Sergey Goncharov, @[email protected], @[email protected], Henning Urbat, and me has been (unconditionally) accepted at ICFP'26! Abstract below ​:Blobhaj_Read_Octopus:​

#icfp #functionalProgramming #programmingLanguages #semantics #coalgebra #categoryTheory

Towards a Higher-Order Bialgebraic Denotational Semantics by Sergey Goncharov, @[email protected], @[email protected], Henning Urbat, and me has been (unconditionally) accepted at ICFP'26! Abstract below ​:Blobhaj_Read_Octopus:​

#icfp #functionalProgramming #programmingLanguages #semantics #coalgebra #categoryTheory

The Tin Bullet: Show&Tell

Aula 1206, Pabellón 0+infinito, lunes, 4 de mayo, 18:30 GMT-3

Buenas! El lunes 4/5 (HOY!!!!) están invitados a la segunda edición de "The Tin Bullet" un evento de micro charlas en la facultad.

La primer edición estuvo muy buena y se trajeron cosas muy piolas. Cópense y vengan a la segunda!

Esta vez vamos a estirar las charlas a 10-15 minutos así hay mas espacio para exponer y consultar.

Al final de la jornada tomamos un mate y charlamos sobre lo expuesto (La ultima vez colmamos MauroIT)

En fin!! Los esperamos <3!!

https://cartelera.inexactas.ar/event/the-tin-bullet-showandtell-1

From 11:00 to 12:00 on Thursday, April 30, the PLUSLE reading group will discuss "Abstract Syntax and Variable Binding" by Marcelo Fiore, Gordon Plotkin, and Daniele Turi.

https://plsl.acp.sdu.dk/posts/2026-04-30-abstract-syntax-and-variable-binding/

#PLUSLE #syntax #programmingLanguages #categoryTheory #lambdaCalculus

Oh joy, another attempt at 'explaining' Category Theory using #orders, because clearly the first thing we all need is more #abstraction in our lives. 🎉 In a groundbreaking revelation, the article tells us orders are about #relationships. 🤯 Who knew binary relations could be so riveting? 🙄
https://abuseofnotation.github.io/category-theory-illustrated/04_order/ #CategoryTheory #HackerNews #HackerNews #ngated

Oh joy, another attempt at 'explaining' Category Theory using #orders, because clearly the first thing we all need is more #abstraction in our lives. 🎉 In a groundbreaking revelation, the article tells us orders are about #relationships. 🤯 Who knew binary relations could be so riveting? 🙄
https://abuseofnotation.github.io/category-theory-illustrated/04_order/ #CategoryTheory #HackerNews #HackerNews #ngated

Category Theory Illustrated – Orders

https://abuseofnotation.github.io/category-theory-illustrated/04_order/

#HackerNews #CategoryTheory #Orders #Illustration #Math #Education #Programming

Category Theory Illustrated – Orders

https://abuseofnotation.github.io/category-theory-illustrated/04_order/

#HackerNews #CategoryTheory #Orders #Illustration #Math #Education #Programming

Someone should make one of those "top 10 most satisfying" videos but for #CategoryTheory diagram chasing proofs

In the mountains, I love exploring nature and climbing any little hidden corner.

My academic interests include mathematics (#mathematics) and mathematical logic ( #mathematicallogic #logic), particularly model theory ( #modeltheory), category theory ( #categorytheory), higher-order logic and metalogic ( #metalogic), as well as the philosophy of mathematics and logic ( #philosophyofmathematics #philosophyoflogic), epistemology and ontology of them.

#introduction

In the mountains, I love exploring nature and climbing any little hidden corner.

My academic interests include mathematics (#mathematics) and mathematical logic ( #mathematicallogic #logic), particularly model theory ( #modeltheory), category theory ( #categorytheory), higher-order logic and metalogic ( #metalogic), as well as the philosophy of mathematics and logic ( #philosophyofmathematics #philosophyoflogic), epistemology and ontology of them.

#introduction

In the mountains, I love exploring nature and climbing any little hidden corner.

My academic interests include mathematics (#mathematics) and mathematical logic ( #mathematicallogic #logic), particularly model theory ( #modeltheory), category theory ( #categorytheory), higher-order logic and metalogic ( #metalogic), as well as the philosophy of mathematics and logic ( #philosophyofmathematics #philosophyoflogic), epistemology and ontology of them.

#introduction

In the mountains, I love exploring nature and climbing any little hidden corner.

My academic interests include mathematics ( #mathematics) and mathematical logic ( #mathematicallogic #logic), particularly model theory ( #modeltheory), category theory ( #categorytheory), higher-order logic and metalogic ( #metalogic), as well as the philosophy of mathematics and logic ( #philosophyofmathematics #philosophyoflogic), epistemology and ontology of them.

#introduction

In the mountains, I love exploring nature and climbing any little hidden corner.

My academic interests include mathematics ( #mathematics) and mathematical logic ( #mathematicallogic #logic), particularly model theory ( #modeltheory), category theory ( #categorytheory), higher-order logic and metalogic ( #metalogic), as well as the philosophy of mathematics and logic ( #philosophyofmathematics #philosophyoflogic), epistemology and ontology of them.

#introduction

Readings shared April 4, 2026. https://jaalonso.github.io/vestigium/posts/2026/04/04-readings_shared_04-04-26 #AI #AI4Math #ATP #Agda #AlphaProof #Autoformalization #CategoryTheory #CoqProver #FunctionalProgramming #ITP #IsabelleHOL #LLMs #LambdaCalculus #LeanProver #Lisp #Logic #LogicProgramming #LLMs #Math #Physics #Programming #Prolog #Racket #RocqProver #Vampire

Readings shared April 4, 2026. https://jaalonso.github.io/vestigium/posts/2026/04/04-readings_shared_04-04-26 #AI #AI4Math #ATP #Agda #AlphaProof #Autoformalization #CategoryTheory #CoqProver #FunctionalProgramming #ITP #IsabelleHOL #LLMs #LambdaCalculus #LeanProver #Lisp #Logic #LogicProgramming #LLMs #Math #Physics #Programming #Prolog #Racket #RocqProver #Vampire

Category theory illustrated: Types. ~ Jencel Panic. https://abuseofnotation.github.io/category-theory-illustrated/06_type/ #CategoryTheory #Math

Category theory illustrated: Types. ~ Jencel Panic. https://abuseofnotation.github.io/category-theory-illustrated/06_type/ #CategoryTheory #Math

What Category Theory Teaches Us About DataFrames

https://mchav.github.io/what-category-theory-teaches-us-about-dataframes/

#HackerNews #CategoryTheory #DataFrames #DataScience #Programming #HackerNews

What Category Theory Teaches Us About DataFrames

https://mchav.github.io/what-category-theory-teaches-us-about-dataframes/

#HackerNews #CategoryTheory #DataFrames #DataScience #Programming #HackerNews

Thanks to our speakers and @Stiephen all the slides for PSSL 112 are now available on the PSSL website! https://sites.google.com/view/pssl112/program

#CategoryTheory #Logic

Thanks to our speakers and @Stiephen all the slides for PSSL 112 are now available on the PSSL website! https://sites.google.com/view/pssl112/program

#CategoryTheory #Logic

Published a new chapter of #categorytheoryillustrated - Types

https://abuseofnotation.github.io/category-theory-illustrated/06_type/

#categorytheory #mathematics #haskell

Published a new chapter of #categorytheoryillustrated - Types

https://abuseofnotation.github.io/category-theory-illustrated/06_type/

#categorytheory #mathematics #haskell

Readings shared March 29, 2026. https://jaalonso.github.io/vestigium/posts/2026/03/30-readings_shared_02-29-26 #AI #AI4Math #CategoryTheory #ITP #LeanProver #Logic #Math #Programming

Readings shared March 29, 2026. https://jaalonso.github.io/vestigium/posts/2026/03/30-readings_shared_02-29-26 #AI #AI4Math #CategoryTheory #ITP #LeanProver #Logic #Math #Programming

Formally verifying digital circuits with category theory in Lean. ~ Matt Hunzinger. https://matt.hunzinger.me/2026/03/28/circuits.html #LeanProver #ITP #CategoryTheory

Formally verifying digital circuits with category theory in Lean. ~ Matt Hunzinger. https://matt.hunzinger.me/2026/03/28/circuits.html #LeanProver #ITP #CategoryTheory

RE: https://fosstodon.org/@zurihac/116040336310097135

Come meet me there!

#categorytheory #haskell

RE: https://fosstodon.org/@zurihac/116040336310097135

Come meet me there!

#categorytheory #haskell

Question for people with background in #categorytheory , which of the two is more correct/understandable:

"A monoid is...

#categorytheoryillustrated

Question for people with background in #categorytheory , which of the two is more correct/understandable:

"A monoid is...

#categorytheoryillustrated

Readings shared March 09, 2026. https://jaalonso.github.io/vestigium/posts/2026/03/10-readings_shared_02-09-26 #AI #AI4Math #CategoryTheory #CoqProver #Emacs #FunctionalProgramming #Haskell #ITP #IsabelleHOL #LambdaCalculus #LeanProver #Lisp #Math #Physics #RocqProver