“Selection functions and lenses,” from @julesh https://julesh.com/posts/2021-03-30-selection-functions-lenses.html

Flashback to this very short blog post I wrote 5 years ago: Selection functions and lenses https://julesh.com/posts/2021-03-30-selection-functions-lenses.html

Part 5 in the increasingly inaccurately named European Trilogy

I guess we formalised "make no mistakes"

Only you can prevent entropy

One simple practical way to fight against corporations and some of the other bad people is to randomly interleave sexual content with serious work. For slightly complicated historical reasons most of them are puritan (the same ones we expelled from Europe back in the day) so I suspect it sort of […]

A mathematician is a device for turning coffee into eepiness

bro just one more coffee bro one more coffee will fix it bro I swear

Wir müssen wissen *audio distortion kicks in* Wir werden wissen *bass drops*

Functors Lens → Set are the same thing as strong profunctors Setᵒᵖ x Set → Set (the Tambara representation theorem), so "dependent strong profunctors" on Set can probably be usefully *defined* to be functors Poly → Set

Sequence of increasingly mind-blowing realisations: - Every polynomial functor of the form ayᵃ is canonically a comonoid for the composition product - aka polynomial comonad - aka category - these are precisely the indiscrete categories (the ones where there is exactly 1 morphism between each […]

*Taps the sign* There is no royal road to mathematics

We have foundations crisis at home

Is that a large cardinal in your pocket or are you just pleased to see me

Self-OH: "I'm starting to think that categories might be really important... maybe even as important as additive containers"

An LLM is a device for turning water into theorems

Which is to say, proving hard Theorems is pretty neat, but it is entirely unrelated to the subject that I do professionally. I have never proved a single Theorem in my entire life.

I sure am glad to be a bird and not a frog

Throwback to this gnarly trilogy of blog posts I wrote 3 years ago: "Monadic lenses are the optic for right monad modules" Part 1: https://julesh.com/posts/2023-06-07-monadic-lenses-optic-right-monad-modules-i.html Part 2 […]

Building my website locally is a *serious* installation, it has both Haskell and OCaml as prerequisites, and a whole lot of haskell libraries

Maybe it's just me, but I kinda feel that recently my social media feed has gone past the traditional decades-old baseline of *doom* and into a new level of *despair*

Big day for me: I'm migrating the domain registration of https://julesh.com into Europe, specifically from Godaddy to OVH The website might go down for a bit, depending on whether it copies the DNS records that connect it to Github Pages (which I will also be migrating away from, but one step […]

Maybe you could characterise my recurring dreams and wandering mind by "what if Mad Max but for architecture instead of vehicles"

RE: https://mathstodon.xyz/@julesh/117095810329013013 Major update to the UK government's response so far to this summer's climate meltdown: 1) approve new fossil fuel drilling 2) deploy the national emergency alert system to tell us that they have banned disposable bbqs, and 3) tell everyone […]

julesh@julesh.mathstodon.xyz.ap.brid.gy · last mo.

So let me get this straight, the government's response so far to this summer's climate meltdown has been to: 1) approve new fossil fuel drilling, and 2) deploy the national emergency alert system to tell us that they have banned disposable bbqs

I guess the same feature of Javascript that we used in the 90s to get cute animations following the mouse pointer is what is now used to biometrically fingerprint your hand movements on every webpage

Hypodrive (device that allows you to travel through space extremely slowly)

I might have to write a blog post building up an explanation of this little bit of code. This is a way of handling mutable local state in lenses, using (1) an old Lisp trick called for simulating OOP, and (2) the fact that categories are comonoids of the composition product of polynomial functors

Misinformation RE: https://mathstodon.xyz/@johncarlosbaez/117206475161888003

"Average tech salary is high" factoid statistically false. Senior Machine Learning Engineer Georg, who lives in a cave and has a salary of 1,000,000 per year, is a statistical outlier adn should not have been counted

Misinformation RE: https://mathstodon.xyz/@johncarlosbaez/117206475161888003