Uploaded December 2025 | Updated September 2026, 2 weeks ago
Oxford Seminar, December 4 2025
Speaker: Matteo Capucci
Full Title: A Second Taste of Quantitative Logic
Abstract: In this second talk I will introduce p-means and argue they form a good quantitative analogue of first-order quantifiers. I will then sketch the construction of a hyperdoctrine valued in enriched graded preorders which forms the intended semantics of a first-order quantitative linear logic.
Oxford Seminar, December 4 2025
Speaker: Matteo Capucci
Full Title: A Second Taste of Quantitative Logic
Abstract: In this second talk I will introduce p-means and argue they form a good quantitative analogue of first-order quantifiers. I will then sketch the construction of a hyperdoctrine valued in enriched graded preorders which forms the intended semantics of a first-order quantitative linear logic.
![[DOTS Lectures] 13. A general representability theorem for Systems Theory Pt. 3
Part of a lecture series on the Double Operadic Theory of Systems (DOTS) presented by David Jaz Myers.
Some material from these lectures can be found in Davids book on categorical systems theory:
https://www.davidjaz.com/Papers/DynamicalBook.pdf [DOTS Lectures] 13. A general representability theorem for Systems Theory Pt. 3](https://i.ytimg.com/vi/BST8hBWS1Kw/mqdefault.jpg)
![[2-torial] Quantum information theory, Part 3: Quantum bird watching
2-torial, May 20 2026
You can find accompanying notes and other information on this video at https://topos.institute/work/lectures/2-torials/2026-05-20_hosgood_quantum/
Tutor: Tim Hosgood
Tutee: Jason Brown
The elements of quantum information theory are not so complicated: some linear algebra over the complex numbers and a bit of classical probability theory. But it doesnt take long before you run into some intriguing problems that showcase how established experimental results contradict our classical intuition. In this 2-torial we will learn the very basics of quantum theory, see how a Mach–Zehnder interferometer gives a real-world implementation of a classically impossible construction and suggests that we should go all in on complex numbers, and finally how this all applies to the world of theoretical bird watching via the Quantum Zeno effect. [2-torial] Quantum information theory, Part 3: Quantum bird watching](https://i.ytimg.com/vi/BfX-vy47fZw/mqdefault.jpg)
![Adrian Miranda: Kleisli constructions for pseudomonads
Topos Institute Colloquium, 30th of January 2025.
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The passage from a monad (A,S) to its category of algebras (resp. category of free algebras) can be seen as a V = Cat weighted limit (resp. colimit) construction [1]. The colimit case also has a description involving maps of the form X to SY and the so-called Kleisli composition.
When we move to the two-dimensional setting, the 2-category of pseudoalgebras can be seen as a V= Gray enriched weighted limit [2], but neither of the familiar descriptions of the Kleisli category categorify to give a weighted colimit [3]. We give a third, less well-known description of the Kleisli category which does categorify to the pseudomonad setting to give a weighted colimit. We show that comparisons induced by pseudoadjunctions splitting the pseudomonad are biequivalences if and only if their left pseudoadjoints are biessentially surjective on objects. This allows the more familiar Kleisli constructions for pseudomonads to be seen as tricategorical colimits, and for the development of the formal theory of pseudomonads pt. 2. Adrian Miranda: Kleisli constructions for pseudomonads](https://i.ytimg.com/vi/BksyGqtwjyg/mqdefault.jpg)
![[Berkeley Seminar] Ea Thompson | A Characterization of Pro-representable Virtual Double Categories
Title: A Characterization of Pro-representable Virtual Double Categories
Abstract: Virtual double categories have been shown to provide an effective framework for formal category theory, from characterizations of adjoints and liftings to descriptions of pointwise Kan extensions and Yoneda structures. In studying virtual double categories themselves, an interesting question comes from asking what kind of structure virtual double categories are enriched over. In this talk, we take a first step in answering this question by characterizing the exponentiable, or pro-representable, virtual double categories. We will provide examples of pro-representable virtual double categories, including pseudo double categories and cospan virtual double categories, while also providing a simple counter-example to the claim that all virtual double categories are exponentiable. If there is time, we will discuss another internal-hom candidate coming from Libkind, Myers, Carlson, and Brown’s theory of loose bimodules. [Berkeley Seminar] Ea Thompson | A Characterization of Pro-representable Virtual Double Categories](https://i.ytimg.com/vi/CLwKSyVtjLc/mqdefault.jpg)


![Christine Tasson: Semantics for Reactive Probabilistic Programming
Topos Institute Colloquium, 12th of September 2024.
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Synchronous languages are now a standard industry tool for critical embedded systems. Designers write high-level specifications by composing streams of values. These languages have been extended with Bayesian reasoning to program state-space models which compute a stream of distributions given a stream of observations [1].
This talk aims at describing semantics for probabilistic synchronous languages, based on a joint work with Guillaume Baudart and Louis Mandel [2]. The key idea is to interpret probabilistic expressions as a stream of un-normalized density functions which maps random variable values to a result and positive score. Two equivalent semantics are presented: the co-iterative semantics is executable while the relational semantics is easy to use for proving program equivalence. The semantical framework is then applied to prove the correctness of a program transformation required to run an optimized inference algorithm.
[1] Reactive Probabilistic Programming, Guillaume Baudart et al, PLDI 2020
[2] Density-Based Semantics for Reactive Probabilistic Programming, Guillaume Baudart, Louis Mandel, Christine Tasson, arxiv:2308.01676 Christine Tasson: Semantics for Reactive Probabilistic Programming](https://i.ytimg.com/vi/Di8rz9Vp3Rw/mqdefault.jpg)

![[2-torial] Quantum information theory, Part 2: Quantum theory isnt real
2-torial, May 20 2026
You can find accompanying notes and other information on this video at https://topos.institute/work/lectures/2-torials/2026-05-20_hosgood_quantum/
Tutor: Tim Hosgood
Tutee: Jason Brown
The elements of quantum information theory are not so complicated: some linear algebra over the complex numbers and a bit of classical probability theory. But it doesnt take long before you run into some intriguing problems that showcase how established experimental results contradict our classical intuition. In this 2-torial we will learn the very basics of quantum theory, see how a Mach–Zehnder interferometer gives a real-world implementation of a classically impossible construction and suggests that we should go all in on complex numbers, and finally how this all applies to the world of theoretical bird watching via the Quantum Zeno effect. [2-torial] Quantum information theory, Part 2: Quantum theory isnt real](https://i.ytimg.com/vi/EacdwqbOzlY/mqdefault.jpg)
![[Berkeley Seminar] Sophie Libkind | Two takeaways from ACT2Infer
Title: Two takeaways from ACT2Infer
Abstract: In September, David Spivak and I hosted the ACT2Infer workshop which brought together experts in applied category theory and active inference together in order to begin the process of articulating and clarifying the underlying principles of active inference via the formalism of category theory. In this two-part talk Ill (1) share the logistics of hosting this workshop and (2) share my main conceptual takeaway a polynomial functor account of active inference.
https://topos.site/events/berkeley-seminar/ [Berkeley Seminar] Sophie Libkind | Two takeaways from ACT2Infer](https://i.ytimg.com/vi/EcEJQtUAYMs/mqdefault.jpg)
