Jon Sterling › Blog

Lingyuan Ye and I have put on the arXiv a new version of our paper, Domains and Classifying Topoi, which is currently under review.

I’ve been thinking about the Elimination with a Motive transformation as modernised in terms of type theoretic equivalences.

I have made a great deal of progress with Pterodactyl in the past week.

One thing that is still pretty hazy to me is the claimed relationship between “linear types” (qua Cyclone/Rust/OxCaml/Swift/Hylo/etc.) and actual linear logic.

Somehow I have managed to get some time in the past couple weeks to work on my newsreader app, which I had been calling NewsRadar.

It’s well known that unification and subtyping don’t play well together, even in the setting of bidirectional elaboration; the problem, as Amélia Liao very helpfully outlined is scheduling.

In City of Illusions, the Shing have shattered the old League of All Worlds and dominated the Earth—whose people they allow to live quiet pastoral lives subject to only one rarely enforced Law: It Is Wrong To Take Life.

This vacation, my mom came to visit us for two weeks.

A year of reading fiction Reflecting on 2025, the biggest change I have made to my life is that I started reading fiction again after many years of reading only mathematics.

I have continued on my quest to understand and compare different architectures for demand-based/query-based compilation and elaboration.

Please note: I am no longer confident in the conclusions of this post, and I believe that I have made some mistakes.

Definitional proof-irrelevance is all the rage these days.

The thing about universe hierarchies is that they are both painful to implement properly, and punting on them leads to even more pain later on because introducing a hierarchy is an extremely disruptive change for both the system and its libraries.

Last time, I spoke about plans for handling multiple inheritance and implicit coercions in Pterodactyl’s theory preorder.

Project Pterodactyl aims to support coherent algebraic hierarchies with multiple inheritance as well as user-defined edges.

After a few very enlightening conversations following my HoTTEST seminar talk “Is it time for a new proof assistant?”

Mason Freed, a Chromium/Blink developer employed by Google, opened a ticket a couple weeks ago on the WHATWG/html repository: Shall we remove XSLT from the web platform?

During my Summer holiday, I began working on a new newsreader for the Macintosh which I have tentatively named NewsRadar.

Frank Herbert’s God Emperor of Dune is the most delightfully unhinged novel I have ever read.

As many predicted, Apple unveiled at its Worldwide Developer Conference a new design language for all its platforms centred around a material that they call Liquid Glass.

On Tuesday, I travelled by train to Sheffield to take part in the Yorkshire and Midlands Category Theory Seminar #37 meeting, where I would be speaking about my paper that compares partial map classifiers with Sierpiński cones in synthetic (domain/categor…

Over the Christmas holiday, I bought an iMac off eBay for £50.

Moments before leaving for a meeting in Barbados with my colleagues Anil Madhavapeddy and Mark Elvers, I hastily loaded Arthur C.

Two months ago I reviewed Harry Harrison’s delightful West of Eden, a piece of speculative fiction that considers a world in which the Cretaceous–Paleogene extinction event never occurred, and one species of dinosaur went on to evolve over the subsequent…

I have found that one could do far worse than perusing the r/CoolSciFiCovers subreddit and picking things to read at random.

How can we effectively and sustainably fund the intellectual infrastructure for generational human advancement?

I am a proponent of using plain text (or Markdown-formatted) emails rather than HTML-formatted emails.

I have been thinking about monoidal closed structures induced by slicing over a monoid, which has been considered by Combette and Munch-Maccagnoni as a potential denotational semantics of destructors à la C++.

I have been thinking again about the relationship between quantitative type theory and synthetic Tait computability and other approaches to type refinements.

For any small category \mathscr {C}, Fiore treats \mathscr {C}-sorted abstract syntax in the functor category {\mathopen {}\left [\mathscr {C},\operatorname {Pr}{\mathopen {}\left (\operatorname {\mathbb {L}}{\mathscr {C}}\right )\mathclose {}}\right ]\ma…

I have long been an enthusiast for outliners, a genre of computer software that deserves more than almost any other to be called an “elegant weapon for a more civilized age”.

Lurie states the following result as Proposition 7.2.1.14 of Higher Topos Theory: Let \mathcal {X} be an ∞-topos and let {\mathcal {X}}\xrightarrow {{\tau _{\leq 0}}}{\tau _{\leq 0}\mathcal {X}} be the left adjoint to the inclusion.