Just out: Functional Data Structures, edited by Tobias Nipkow

The Weak Spectroscopy Game to Characterize Behavioral Equivalences Lisa Barthel et al We formalise Bisping and Jansen's weak spectroscopy game, which can be used to characterize and decide a hierarchy of behavioral equivalences for systems with internal behavior. www.isa-afp.org/entries/Weak...

Rely-Guarantee Extensions and Locks RJ Colvin et al We extend the existing rely-guarantee library with flexible syntax, data-invariant support, etc. We apply our library to three queue locks: the Abstract Queue Lock, the Ticket Lock, and the Circular Buffer Lock. www.isa-afp.org/entries/RG_L...

New on my blog: Set theory with types lawrencecpaulson.github.io/2025/11/21/T...

Discrete Upper Confidence Bound Algorithm in HOL by A Faber He formally verifies the Discrete Upper Confidence Bound (UCB) algorithm, focusing on its probabilistic guarantees and regret bounds. The work explores verification of discrete-time bandit models. www.isa-afp.org/entries/Disc...

Pre*: The Predecessors of a Regular Language wrt a Context-Free Grammar T Lemke & T Nipkow Let L be a language, G a cfg and Pre*(L) the set of all predecessors of words in L. If L is regular so is Pre*(L). We formalize 2 algorithms to compute Pre*(L) for regular L. www.isa-afp.org/entries/Pre_...

Sometimes, a front page can sum up quite a lot that’s wrong with the world. Including the paper itself which has been so complicit in getting us to a place where children born to refugees could be deported, Trump celebrates despotic wealth and Boris Johnson’s sister moans about not being rich. Ugh.

New in the AFP: Formalizing Neural Networks A Brucker & A Stell The use of deep learning is constrained by the lack of verification techniques. We address this issue by formalizing an important class of neural networks, feed-forward neural networks, in Isabelle. www.isa-afp.org/entries/Neur...

A nice profile of Marijn Heule and his work www.quantamagazine.org/to-have-mach...

A new version of a talk I've given many times: formalising the Diagonal Ramsey paper youtu.be/YO-LUhUxtFc

New on my blog: "Why don't you use dependent types?" lawrencecpaulson.github.io/2025/11/02/W...

New in the AFP: Path Equivalence and Automation for Integration Contours by M Eberl Formalises concepts to ease manipulation of paths. Provides the path tactic, which simplifies some proof obligations for composite paths, eg decomposing integrals on a composite path. www.isa-afp.org/entries/Path...

New in the AFP: Muntac: A Verified Certificate Checker for Timed Automata S Wimmer Munta is a verified model checker for timed automata. Muntac is an extension of Munta that can check certificates for Büchi and reachability properties from other model checkers. www.isa-afp.org/entries/Munt...

New in the AFP: Pushdown Automata Kaan Taskin, Tobias Nipkow This entry formalizes pushdown automata and proves their equivalence with context-free grammars. It also shows that acceptance by empty stack and by final state are equivalent. www.isa-afp.org/entries/Push...

New in the AFP: Z Mathematical Toolkit by S Foster et al We construct the Z metalanguage and type universe and link this to types in Isabelle, to enable efficient proof automation. We use coercive subtyping and overloading to support Z-like expressions. www.isa-afp.org//entries/Z_T...

In an interview with Bloomberg, Farage has said that Nathan Gill was "one bad apple" - unintentionally being accurate because he forgot the rest of the proverb.

New on my blog: Most proofs are trivial lawrencecpaulson.github.io/2025/10/15/P...

New in the AFP: Relational Divisibility by W Guttmann We formalise key concepts and axioms of the divisibility relation on natural numbers using relation algebras. They use standard relational constructions for extrema, bounds, suprema, ... www.isa-afp.org/entries/Rela...

From the FT

My ITP paper is now out: Formalising New Mathematics in Isabelle: Diagonal Ramsey doi.org/10.4230/LIPI...

New on my blog: Everything you know is wrong lawrencecpaulson.github.io/2025/09/20/W...

Reminder: The existence of these in most Scottish supermarkets and corner shops is proof that anyone shilling for the notion that multiculturalism can't work on this island is a charlatan

From Feb 4th 1939

This 👇 theonion.com/in-defense-o...