Tom de Jong
Postdoc at the University of Nottingham working on type theory. PhD from the University of Birmingham. Mathematician, computer scientist and runner.
Postdoc at the University of Nottingham working on type theory. PhD from the University of Birmingham. Mathematician, computer scientist and runner.
i've always admired and sometimes envied people who can think very quickly, in front of others. it's taken me a long time to appreciate slow and solitary thinking (which i relate to more naturally) as a complementary skill, but i hope i can do some good in the world by talking about it. if you process things slowly, you're probably noticing a lot more detail, taking less for granted. sharing what you learn, even at long delay, is a gift you may give others patient enough to deserve it
@pigworker @jonmsterling The Windows 95 launch used "Start Me Up" by The Rolling Stones, which was an apt choice, but only because the chorus goes "You make a grown man cry".
At 9.50 today, I'm giving a talk on constructive domain theory at the Formal Topology Workshop in Venice. Feat. a shoutout to @nmvdw and @dif for their nice paper "The Interval Domain in Homotopy Type Theory".
It should be livestreamed: https://youtube.com/@wires0/streams
[Update: it seems the recording of my talk failed.]
I'm pleased, especially for our PhD student @aref_mz, that our paper "Generalized Decidability via Brouwer Trees" (https://arxiv.org/abs/2602.10844) with @aref_mz, @Nicolai_Kraus and @fnf was accepted to LICS'26.
#Agda was very useful for developing this work. Huge thanks to its maintainers!
My commiserations to those who submitted good work but didn't get in. I hope we can all escape this system one day.
@ToucanIan
Maybe you'll find https://doi.org/10.1016/j.entcs.2012.08.009 (and related work by Cockett and others) interesting.
This week the #HoTTEST seminar presents:
Freek Geerligs
Synthetic Stone duality
The talk is at 11:30am EDT (15:30 UTC) on Thursday, April 16. The talk will be 60 minutes long, followed by up to 30 minutes for questions. See https://hottest-seminar.github.io/ for the Zoom link and a list of all upcoming talks.
All are welcome!
Abstract:
In this talk, we will give an overview of Synthetic Stone duality (https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.TYPES.2024.3). We will then discuss some related work in progress.
Synthetic Stone duality is an extension of homotopy type theory with four axioms. These axioms are strong enough to decide Bishop's omniscience principles. We introduce a (synthetic) topology on any type, such that all functions are continuous. We are interested in Stone spaces and compact Hausdorff spaces, where the topology behaves as one would expect. In particular, we can define the (topological) interval and show that all functions are continuous in the epsilon-delta sense.
Currently, we are working on a paper with a method for calculating cohomology with countably presented coefficients for compact Hausdorff spaces. We are also interested in a correspondence between homotopical concepts defined using traditional topology (using paths from the topological interval) and homotopy type theory (using identity types).
This talk will contain joint work with Reid Barton, Felix Cherubini, Thierry Coquand, and Hugo Moeneclaey.
We're happy to announce that we are accepting applications for studentships & subsidised accommodation for SPLV'26:
https://spli.scot/splv/2026-glasgow/
To apply, please fill in the following form by April 27th. We will get back to you shortly after this date.
https://tinyurl.com/splv-pre-registration-26
There should be plenty of accommodation. We will prioritise studentship applications from SPLI institutions but may be able to offer some more widely.
Early registration will open at the end of April. More details soon!
I'm on the PC of Computer Science Logic (CSL 2027). https://csl2027.github.io/
The abstract/paper submission deadlines are 8/15 July 2026 (AoE) with notification of accepted papers on 15 October 2026, and the conference itself on 25-29 January 2027 in Brighton.
I would love to see papers on the following subset of relevant topics:
* category theory
* constructive mathematics
* denotational semantics
* domain theory
* interactive theorem proving
* realizability
* type theory
Sam Speight kicking off MGS 2026 with Lambda Calculus and Combinatory Algebra
There are still a few weeks left to submit papers and extended abstracts to the Workshop on Mathematically Structured Functional Programming: https://msfp-workshop.github.io/msfp2026/ I'm on the PC and would love to see what you've been up to!
"In the UK, a quarter of total university income is generated by international students, who pay much higher fees than home students. To attract them, British universities rely on vast, largely unregulated networks of agents operating primarily in Asia and Africa."
"The reason British universities spend so much to attract international students is simple: if they were to rely solely on home students, they would go bust."
What could possibly go wrong ... with university finances. This system is not well-grounded, not reliable or stable in any way or form.
Registration is now open for HoTT/UF 2026! Hope to see some of you in Aarhus soon 😃
See https://hott-uf.github.io/2026/ for registration details.
@danielgratzer Will there be (limited) options for remote participation? (I believe the original calls mentioned this, but might be wrong.)
If so, should remote participants register too?
Gothenburg University is hiring a postdoc to work on compilation of cubical programs: https://web103.reachmee.com/ext/I005/1035/job?site=7&lang=UK&validator=9b89bead79bb7258ad55c8d75228e5b7&job_id=40092
Very cool project with lots of potential and interesting research problems to solve. Please help spreading it to interested candidates!
@clayrat This paper does not show that the free topos validates countable choice (it doesn't), although it is easy to mistake it for saying that.
@johncarlosbaez @dougmerritt @MartinEscardo @JacquesC2 @pigworker @xenaproject Well, it should be obvious, but let me say it anyway.
We need mathematicians of every kind: the thinkers, the dreamers, the formalizers, and even physicists.
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
