Categorical Semantics of Entropy

19 April, 2022

There will be a workshop on the categorical semantics of entropy at the CUNY Grad Center in Manhattan on Friday May 13th, organized by John Terilla. I was kindly invited to give an online tutorial beforehand on May 11, which I will give remotely to save carbon. Tai-Danae Bradley will also be giving a tutorial that day in person:

Tutorial: Categorical Semantics of Entropy, Wednesday 11 May 2022, 13:00–16:30 Eastern Time, Room 5209 at the CUNY Graduate Center and via Zoom. Organized by John Terilla. To attend, register here.

12:00-1:00 Eastern Daylight Time — Lunch in Room 5209.

1:00-2:30 — Shannon entropy from category theory, John Baez, University of California Riverside; Centre for Quantum Technologies (Singapore); Topos Institute.

Shannon entropy is a powerful concept. But what properties single out Shannon entropy as special? Instead of focusing on the entropy of a probability measure on a finite set, it can help to focus on the “information loss”, or change in entropy, associated with a measure-preserving function. Shannon entropy then gives the only concept of information loss that is functorial, convex-linear and continuous. This is joint work with Tom Leinster and Tobias Fritz.

2:30-3:00 — Coffee break.

3:00-4:30 — Operads and entropy, Tai-Danae Bradley, The Master’s University; Sandbox AQ.

This talk will open with a basic introduction to operads and their representations, with the main example being the operad of probabilities. I’ll then give a light sketch of how this framework leads to a small, but interesting, connection between information theory, abstract algebra, and topology, namely a correspondence between Shannon entropy and derivations of the operad of probabilities.

Symposium on Categorical Semantics of Entropy, Friday 13 May 2022, 9:30-3:15 Eastern Daylight Time, Room 5209 at the CUNY Graduate Center and via Zoom. Organized by John Terilla. To attend, register here.

9:30-10:00 Eastern Daylight Time — Coffee and pastries in Room 5209.

10:00-10:45 — Operadic composition of thermodynamic systems, Owen Lynch, Utrecht University.

The maximum entropy principle is a fascinating and productive lens with which to view both thermodynamics and statistical mechanics. In this talk, we present a categorification of the maximum entropy principle, using convex spaces and operads. Along the way, we will discuss a variety of examples of the maximum entropy principle and show how each application can be captured using our framework. This approach shines a new light on old constructions. For instance, we will show how we can derive the canonical ensemble by attaching a probabilistic system to a heat bath. Finally, our approach to this categorification has applications beyond the maximum entropy principle, and we will give an hint of how to adapt this categorification to the formalization of the composition of other systems.

11:00-11:45 — Polynomial functors and Shannon entropy, David Spivak, MIT and the Topos Institute.

The category Poly of polynomial functors in one variable is extremely rich, brimming with categorical gadgets (e.g. eight monoidal products, two closures, limits, colimits, etc.) and applications including dynamical systems, databases, open games, and cellular automata. In this talk I’ll show that objects in Poly can be understood as empirical distributions. In part using the standard derivative of polynomials, we obtain a functor to Set × Setop which encodes an invariant of a distribution as a pair of sets. This invariant is well-behaved in the sense that it is a distributive monoidal functor: it acts on both distributions and maps between them, and it preserves both the sum and the tensor product of distributions. The Shannon entropy of the original distribution is then calculated directly from the invariant, i.e. only in terms of the cardinalities of these two sets. Given the many applications of polynomial functors and of Shannon entropy, having this link between them has potential to create useful synergies, e.g. to notions of entropic causality or entropic learning in dynamical systems.

12:00-1:30 — Lunch in Room 5209

1:30-2:15 — Higher entropy, Tom Mainiero, Rutgers New High Energy Theory Center.

Is the frowzy state of your desk no longer as thrilling as it once was? Are numerical measures of information no longer able to satisfy your needs? There is a cure! In this talk we’ll learn about: the secret topological lives of multipartite measures and quantum states; how a homological probe of this geometry reveals correlated random variables; the sly decategorified involvement of Shannon, Tsallis, Réyni, and von Neumann in this larger geometric conspiracy; and the story of how Gelfand, Neumark, and Segal’s construction of von Neumann algebra representations can help us uncover this informatic ruse. So come to this talk, spice up your entropic life, and bring new meaning to your relationship with disarray.

2:30-3:15 — On characterizing classical and quantum entropy, Arthur Parzygnat, Institut des Hautes Études Scientifiques.

In 2011, Baez, Fritz, and Leinster proved that the Shannon entropy can be characterized as a functor by a few simple postulates. In 2014, Baez and Fritz extended this theorem to provide a Bayesian characterization of the classical relative entropy, also known as the Kullback–Leibler divergence. In 2017, Gagné and Panangaden extended the latter result to include standard Borel spaces. In 2020, I generalized the first result on Shannon entropy so that it includes the von Neumann (quantum) entropy. In 2021, I provided partial results indicating that the Umegaki relative entropy may also have a Bayesian characterization. My results in the quantum setting are special applications of the recent theory of quantum Bayesian inference, which is a non-commutative extension of classical Bayesian statistics based on category theory. In this talk, I will give an overview of these developments and their possible applications in quantum information theory.

Wine and cheese reception to follow, Room 5209.

Applied Category Theory 2022

25 February, 2022

The Fifth International Conference on Applied Category Theory, ACT2022, will take place at the University of Strathclyde from 18 to 22 July 2022, preceded by the Adjoint School 2022 from 11 to 15 July. This conference follows previous events at Cambridge (UK), Cambridge (MA), Oxford and Leiden.

Applied category theory is important to a growing community of researchers who study computer science, logic, engineering, physics, biology, chemistry, social sciences, linguistics and other subjects using category-theoretic tools. The background and experience of our members is as varied as the systems being studied. The goal of the Applied Category Theory conference series is to bring researchers together, strengthen the applied category theory community, disseminate the latest results, and facilitate further development of the field.


We accept submissions in English of original research papers, talks about work accepted/submitted/published elsewhere, and demonstrations of relevant software. Accepted original research papers will be published in a proceedings volume. The keynote addresses will be chosen from the accepted papers. The conference will include an industry showcase event and community meeting. We particularly encourage people from underrepresented groups to submit their work and the organizers are committed to non-discrimination, equity, and inclusion.

Submission formats

Extended Abstracts should be submitted describing the contribution and providing a basis for determining the topics and quality of the anticipated presentation (1-2 pages). These submissions will be adjudicated for inclusion as a talk at the conference. Such work should include references to any longer papers, preprints, or manuscripts providing additional details.

Conference Papers should present original, high-quality work in the style of a computer science conference paper (up to 14 pages, not counting the bibliography; detailed proofs may be included in an appendix for the convenience of the reviewers). Such submissions should not be an abridged version of an existing journal article (see item 1) although pre-submission Arxiv preprints are permitted. These submissions will be adjudicated for both a talk and publication in the conference proceedings.

Software Demonstrations should be submitted in the format of an Extended Abstract (1-2 pages) giving the program committee enough information to assess the content of the demonstration. We are particularly interested in software that makes category theory research easier, or uses category theoretic ideas to improve software in other domains.

Extended abstracts and conference papers should be prepared with LaTeX. For conference papers please use the EPTCS style files available at

The submission link is

Important dates

The following dates are all in 2022, and Anywhere On Earth.

• Submission Deadline: Monday 9 May
• Author Notification: Tuesday 7 June
• Camera-ready version due: Tuesday 28 June
• Adjoint School: Monday 11 to Friday 15 July
• Main Conference: Monday 18 to Friday 22 July

Conference format

We hope to run the conference as a hybrid event with talks recorded or streamed for remote participation. However, due to the state of the pandemic, the possibility of in-person attendance is not yet confirmed. Please be mindful of changing conditions when booking travel or hotel accommodations.

Financial support

Limited financial support will be available. Please contact the organisers for more information.

Program committee

• Jade Master, University of Strathclyde (Co-chair)
• Martha Lewis, University of Bristol (Co-chair)

The full program committee will be announced soon.

Organizing committee

• Jules Hedges, University of Strathclyde
• Jade Master, University of Strathclyde
• Fredrik Nordvall Forsberg, University of Strathclyde
• James Fairbanks, University of Florida

Steering committee

• John Baez, University of California, Riverside
• Bob Coecke, Cambridge Quantum
• Dorette Pronk, Dalhousie University
• David Spivak, Topos Institute

Categories in Chemistry, Computing, and Social Networks

26 January, 2022

This article does two things:

• John Baez, Simon Cho, Daniel Cicala, Nina Otter, and Valeria de Paiva, Applied category theory in chemistry, computing, and social networks, Notices of the American Mathematical Society, February 2022.

It urges you — or your friends, or students — to apply for our free summer school in applied category theory run by the American Mathematical Society. It’s also a quick intro to some key ideas in applied category theory!

Applications are due Tuesday 2022 February 15 at 11:59 Eastern Time — go here for details. If you get in, you’ll get an all-expenses-paid trip to a conference center in upstate New York for a week in the summer. There will be a pool, bocci, lakes with canoes, woods to hike around in, campfires at night… and also whiteboards, meeting rooms, and coffee available 24 hours a day.

You can work with me on categories in chemistry, Nina on categories in the study of social networks, or Valeria on categories applied to concepts from computer science, like lenses.

There are also other programs to choose from. Read this, and click for more details:

Adjoint School 2022

2 January, 2022

Every year since 2018 we’ve been having annual courses on applied category theory where you can do research with experts. It’s called the Adjoint School.

You can apply to be a student at the 2022 Adjoint School now, and applications are due February 4th! Go here:

2022 Adjoint School: application.

The school will be run online from February to June, 2022, and then—coronavirus permitting—there will be in-person research at the University of Strathclyde in Glasgow, Scotland the week of July 11 – 15, 2022. This is also the location of the applied category theory conference ACT2022.

The 2022 Adjoint School is organized by Angeline Aguinaldo, Elena Di Lavore, Sophie Libkind, and David Jaz Myers. You can read more about how it works here:

About the Adjoint School.

There are four topics to work on, and you can see descriptions of them below.

Who should apply?

Anyone, from anywhere in the world, who is interested in applying category-theoretic methods to problems outside of pure mathematics. This is emphatically not restricted to math students, but one should be comfortable working with mathematics. Knowledge of basic category-theoretic language—the definition of monoidal category for example—is encouraged.

We will consider advanced undergraduates, PhD students, post-docs, as well as people working outside of academia. Members of groups which are underrepresented in the mathematics and computer science communities are especially encouraged to apply.

Also check out our inclusivity statement.

Topic 1: Compositional Thermodynamics

Mentors: Spencer Breiner and Joe Moeller

TA: Owen Lynch

Description: Thermodynamics is the study of the relationships between heat, energy, work, and matter. In category theory, we model flows in physical systems using string diagrams, allowing us to formalize physical axioms as diagrammatic equations. The goal of this project is to establish such a compositional framework for thermodynamical networks. A first goal will be to formalize the laws of thermodynamics in categorical terms. Depending on the background and interest of the participants, further topics may include the Carnot and Otto engines, more realistic modeling for real-world systems, and software implementation within the AlgebraicJulia library.


• John C. Baez, Owen Lynch, and Joe Moeller, Compositional thermostatics.

• F. William Lawvere, State categories, closed categories and the existence of semi-continuous entropy functions.

Topic 2: Fuzzy Type Theory for Opinion Dynamics

Mentor: Paige North

TA: Hans Reiss

Description: When working in type theory (or most logics), one is interested in proving propositions by constructing witnesses to their incontrovertible truth. In the real world, however, we can often only hope to understand how likely something is to be true, and we look for evidence that something is true. For example, when a doctor is trying to determine if a patient has a certain condition, they might ask certain questions and perform certain tests, each of which constitutes a piece of evidence that the patient does or does not have that condition. This suggests that a fuzzy version of type theory might be appropriate for capturing and analyzing real-world situations. In this project, we will explore the space of fuzzy type theories which can be used to reason about the fuzzy propositions of disease and similar dynamics.


• Daniel R. Grayson, An introduction to univalent foundations for mathematicians.

• Jakob Hansen and Robert Ghrist, Opinion dynamics on discourse sheaves.

Topic 3: A Compositional Theory of Timed and Probabilistic Processes: CospanSpan(Graph)

Mentor: Nicoletta Sabadini

TA: Mario Román

Description: Span(Graph), introduced by Katis, Sabadini and Walters as a categorical algebra for automata with interfaces, provides, in a very intuitive way, a compositional description of hierarchical networks of interacting components with fixed topology. The algebra also provides a calculus of connectors, with an elegant description of signal broadcasting. In particular, the operations of “parallel with communication” (that allows components to evolve simultaneously, like connected gears), and “non-sequential feedback” (not considered in Kleene’s algebra for classical automata) are fundamental in modelling complex distributed systems such as biological systems. Similarly, the dual algebra Cospan(Graph) allows us to compose systems sequentially. Hence, the combined algebra CospanSpan(Graph), which extends Kleene’s algebra for classical automata, is a general algebra for reconfigurable networks of interacting components. Still, some very interesting aspects and possible applications of this model deserve a better understanding:

• How can timed actions and probability be combined in CospanSpan(Graph)?

• If not, can we describe time-varying probability in a compositional setting?

• Which is the possible role of “parallel with communication” in understanding causality?


• L. de Francesco Albasini, N. Sabadini, and R.F.C. Walters, The compositional construction of Markov processes II.

• A. Cherubini, N. Sabadini, and R.F.C. Walters, Timing in the Cospan-Span model.

Topic 4: Algebraic Structures in Logic and Relations

Mentor: Filippo Bonchi

Description: Fox’s theorem provides a bridge between structures defined by universal properties (products in a category) and structures specified by algebraic means (comonoids in a symmetric monoidal category). Such a theorem has recently received a renewed interest as the algebraic structures allows for reasoning in terms of string diagrams. While the universal properties underlying logical theories have been extensively studied in categorical logic, their algebraic counterparts have been the objects of fewer investigations. This raises a natural question: can we capture the universal content of logical theories algebraically? In other words, what are the ‘Fox theorems’ for logic? In this project, we attempt to answer to this question by taking as starting point Cartesian bicategories which serves as algebraic setting for regular logic.


• Aurelio Carboni and R. F. C. Walters, Cartesian bicategories I.

• Filippo Bonchi, Jens Seeber and Pawel Sobocinski, Graphical conjunctive queries.

• Filippo Bonchi, Dusko Pavlovic and Pawel Sobocinski, Functorial semantics for relational theories.

Learn Applied Category Theory!

27 October, 2021

Do you like the idea of learning applied category theory by working on a project, as part of a team led by an expert? If you’re an early career researcher you can apply to do that now!

Mathematical Research Community: Applied Category Theory, meeting 2022 May 29–June 4. Details on how to apply: here. Deadline to apply: Tuesday 2022 February 15 at 11:59 Eastern Time.

After working with your team online, you’ll take an all-expenses-paid trip to a conference center in upstate New York for a week in the summer. There will be a pool, bocci, lakes with canoes, woods to hike around in, campfires at night… and also whiteboards, meeting rooms, and coffee available 24 hours a day to power your research!

Later you’ll get invited to the 2023 Joint Mathematics Meetings in Boston.

There will be three projects to choose from:

Valeria de Paiva (Topos Institute) will lead a study in the context of computer science that investigates indexed containers and partial compilers using lenses and Dialectica categories.

Nina Otter (Queen Mary University of London) will lead a study of social networks using simplicial complexes.

John Baez (University of California, Riverside) will lead a study of chemical reaction networks using category theoretic methods such as structured cospans.

The whole thing is being organized by Daniel Cicala of the University of New Haven:

and Simon Cho of Two Six Technologies:

I should add that this is just one of four ‘Mathematical Research Communities’ run by the American Mathematical Society in 2022, and you may prefer another. The applied category theory session will be held at the same time and place as one on data science! Then there are two more:

• Week 1a: Applied Category Theory

Organizers: John Baez, University of California, Riverside; Simon Cho, Two Six Technologies; Daniel Cicala, University of New Haven; Nina Otter, Queen Mary University of London; Valeria de Paiva, Topos Institute.

• Week 1b: Data Science at the Crossroads of Analysis, Geometry, and Topology

Organizers: Marina Meila, University of Washington; Facundo Mémoli, The Ohio State University; Jose Perea, Northeastern University; Nicolas Garcia Trillos, University of Wisconsin-Madison; Soledad Villar, Johns Hopkins University.

• Week 2a: Models and Methods for Sparse (Hyper)Network Science

Organizers: Sinan G. Aksoy, Pacific Northwest National Laboratory; Aric Hagberg, Los Alamos National Laboratory; Cliff Joslyn, Pacific Northwest National Laboratory; Bill Kay, Oak Ridge National Laboratory; Emilie Purvine, Pacific Northwest National Laboratory; Stephen J. Young, Pacific Northwest National Laboratory; Jennifer Webster, Pacific Northwest National Laboratory.

• Week 2b: Trees in Many Contexts

Organizers: Miklós Bóna, University of Florida; Éva Czabarka, University of South Carolina; Heather Smith Blake, Davidson College; Stephan Wagner, Uppsala University; Hua Wang, Georgia Southern University.

Applicants should be ready to engage in collaborative research and should be “early career”—either expecting to earn a PhD within two years or having completed a PhD within five years of the date of the summer conference. Exceptions to this limit on the career stage of an applicant may be made on a case-by-case basis. The Mathematical Research Community (MRC) program is open to individuals who are US citizens as well as to those who are affiliated with US institutions and companies/organizations. A few international participants may be accepted. Depending on space and other factors, a small number of self-funded participants may be admitted. Individuals who have once previously been an MRC participant will be considered for admission, and their applications must include a rationale for repeating. Please note that individuals cannot participate in the MRC program more than twice: applications from individuals who have twice been MRC participants will not be considered.

We seek individuals who will both contribute to and benefit from the MRC experience, and the goal is to create a collaborative research community that is vibrant, productive, and diverse. We welcome applicants from academic institutions of all types, as well as from private industry and government laboratories and agencies. Women and under-represented minorities are especially encouraged to apply.

All participants are expected to be active in the full array of MRC activities—the summer conference, special sessions at the Joint Mathematics Meetings, and follow-up collaborations.

Nonequilibrium Thermodynamics in Biology

4 October, 2021

William Cannon and I are organizing a special session on thermodynamics in biology at the American Physical Society March Meeting, which will be held in Chicago on March 14–18, 2022.

If you work on this, please submit an abstract here before October 22! Our session number is 03.01.32.

Non-equilibrium Thermodynamics in Biology: from Chemical Reaction Networks to Natural Selection

Since Lotka, physical scientists have argued that living things belong to a class of complex and orderly systems that exist not despite the second law of thermodynamics, but because of it. Life and evolution, through natural selection of dissipative structures, are based on non-equilibrium thermodynamics. The challenge is to develop an understanding of what the respective physical laws can tell us about flows of energy and matter in living systems, and about growth, death and selection. This session will address current challenges including understanding emergence, regulation and control across scales, and entropy production, from metabolism in microbes to evolving ecosystems.

We have some speakers lined up already. Eric Smith of the Santa Fe Institute will speak on “Combinatorics in evolution: from rule-based systems to the thermodynamics of selectivities”. David Sivak of Simon Fraser University will speak on “”Nonequilibrium energy and information flows in autonomous systems”.

If you have any questions, please ask.

Compositional Robotics (Part 2)

27 May, 2021

Very soon we’re having a workshop on applications of category theory to robotics:

2021 Workshop on Compositional Robotics: Mathematics and Tools, online, Monday 31 May 2021.

You’re invited! As of today it’s not too late to register and watch the talks online, and registration is free. Go here to register:

Here’s the schedule. All times are in UTC, so the show starts at 9:15 am Pacific Time:

Time (UTC) Speaker


16:15-16:30   Intro and plan of the workshop


Jonathan Lorand

Category Theory Basics


John Baez Category Theory and Systems 


Breakout rooms



Andrea Censi
& Gioele Zardini

Categories for Co-Design


David Spivak

Dynamic Interaction Patterns


Breakout rooms



Aaron Ames

A Categorical Perspective on Robotics

21:30-22:15 Daniel Koditschek Toward a Grounded Type Theory for Robot Task Composition
22:30-00:30 Selected speakers Talks from open submissions

For more information go to the workshop website or my previous blog post on this workshop:

Compositional robotics (part 1).

Category Theory and Systems

27 May, 2021

I’m giving a talk on Monday the 31st of May, 2021 at 17:20 UTC, which happens to be 10:20 am Pacific Time for me. You can see my slides here:

Category theory and systems.

I’ll talk about how to describe open systems as morphisms in symmetric monoidal categories, and how to use ‘functorial semantics’ to describe the behavior of open systems.

It’s part of the 2021 Workshop on Compositional Robotics: Mathematics and Tools, and if you click the link you can see how to attend!  If you stick around for the rest of the workshop you’ll hear more concrete talks from people who really work on robotics. 

Compositional Robotics (Part 1)

20 April, 2021

A bunch of us are organizing a workshop on applications of category theory to robotics, as part of the IEEE International Conference on Robotics and Automation:

2021 Workshop on Compositional Robotics: Mathematics and Tools, online, 31 May 2021. Organized by Andrea Censi, Gioele Zardini, Jonathan Lorand, David Spivak, Brendan Fong, Nina Otter, Paolo Perrone, John Baez, Dylan Shell, Jason Kane, Alexandra Nilles, Andew Spielberg, and Emilio Frazzoli.

Submit your papers here by 21 May 2021!

Here’s the idea of the workshop:

In the last decade research on embodied intelligence has seen important developments. While the complexity of robotic systems has dramatically increased, both for single robots and interacting multi-robot systems (e.g., autonomous vehicles and mobility systems), the design methods have not kept up.

The standard answer to dealing with complexity is exploiting compositionality, but there are no well-established mathematical modeling and design tools that have the reach for compositional analysis and design at the level of a complex robotic system.

The goal of this workshop is to integrate mathematical principles and practical tools for compositional robotics, with a focus on applied category theory as a meta-language to talk about compositionality.

The workshop will happen on May 31st virtually. Details will follow.

Session I: Mathematics and Tools for Compositionality

In the morning, some of the world’s leading experts in Applied Category Theory (ACT) will provide tutorials to present an invitation to various aspects of compositionality, both at the theoretical and the practical level. In particular, Dr. Jonathan Lorand will teach Category Theory basics, Dr. David Spivak and Dr. Brendan Fong will introduce the audience to the concept of compositionality, Prof. John Baez will explain how the previously defined concepts can be used when modeling various types of systems, and Dr. Andrea Censi will present the theory of co-design, tailored to robotic applications.

Session II: Keynote Talks and Open Contributions

The afternoon session features two keynotes on the application of compositionality in robotics:

• Prof. Aaron Ames, Bren Professor of Mechanical and Civil Engineering and Control and Dynamical Systems, California Institute of Technology.

• Prof. Daniel Koditschek, Alfred Fitler Moore Professor of Electrical & Systems Engineering, School of Engineering & Applied Science, University of Pennsylvania. Prof. Koditschek will be assisted by Dr. Paul Gustafson (Wright State University) and Dr. Matthew Kvalheim (University of Pennsylvania).

Both speakers are leading experts in their fields and have succesfully applied category theory and compositionality to real challenges in robotics. Finally, we plan for eight talk-slots for open submissions. Submissions should focus on mathematical perspectives (not limited to ACT) and applications of compositionality.

Applied Category Theory 2021 — Call for Papers

16 April, 2021

The deadline for submitting papers is coming up soon: May 12th.

Fourth Annual International Conference on Applied Category Theory (ACT 2021), July 12–16, 2021, online and at the Computer Laboratory of the University of Cambridge.

Plans to run ACT 2021 as one of the first physical conferences post-lockdown are progressing well. Consider going to Cambridge! Financial support is available for students and junior researchers.

Applied category theory is a topic of interest for a growing community of researchers, interested in studying many different kinds of systems using category-theoretic tools. These systems are found across computer science, mathematics, and physics, as well as in social science, linguistics, cognition, and neuroscience. The background and experience of our members is as varied as the systems being studied. The goal of the Applied Category Theory conference series is to bring researchers together, disseminate the latest results, and facilitate further development of the field.

We accept submissions of both original research papers, and work accepted/submitted/ published elsewhere. Accepted original research papers will be invited for publication in a proceedings volume. The keynote addresses will be drawn from the best accepted papers. The conference will include an industry showcase event.

We hope to run the conference as a hybrid event, with physical attendees present in Cambridge, and other participants taking part online. However, due to the state of the pandemic, the possibility of in-person attendance is not yet confirmed. Please do not book your travel or hotel accommodation yet.

Financial support

We are able to offer financial support to PhD students and junior researchers. Full guidance is on the webpage.

Important dates (all in 2021)

• Submission Deadline: Wednesday 12 May
• Author Notification: Monday 7 June
• Financial Support Application Deadline: Monday 7 June
• Financial Support Notification: Tuesday 8 June
• Priority Physical Registration Opens: Wednesday 9 June
• Ordinary Physical Registration Opens: Monday 13 June
• Reserved Accommodation Booking Deadline: Monday 13 June
• Adjoint School: Monday 5 to Friday 9 July
• Main Conference: Monday 12 to Friday 16 July


The following two types of submissions are accepted:

Proceedings Track. Original contributions of high-quality work consisting of an extended abstract, up to 12 pages, that provides evidence of results of genuine interest, and with enough detail to allow the program committee to assess the merits of the work. Submission of work-in-progress is encouraged, but it must be more substantial than a research proposal.

Non-Proceedings Track. Descriptions of high-quality work submitted or published elsewhere will also be considered, provided the work is recent and relevant to the conference. The work may be of any length, but the program committee members may only look at the first 3 pages of the submission, so you should ensure that these pages contain sufficient evidence of the quality and rigour of your work.

Papers in the two tracks will be reviewed against the same standards of quality. Since ACT is an interdisciplinary conference, we use two tracks to accommodate the publishing conventions of different disciplines. For example, those from a Computer Science background may prefer the Proceedings Track, while those from a Mathematics, Physics or other background may prefer the Non-Proceedings Track. However, authors from any background are free to choose the track that they prefer, and submissions may be moved from the Proceedings Track to the Non-Proceedings Track at any time at the request of the authors.

Contributions must be submitted in PDF format. Submissions to the Proceedings Track must be prepared with LaTeX, using the EPTCS style files available at

The submission link will soon be available on the ACT2021 web page:

Program Committee


• Kohei Kishida, University of Illinois, Urbana-Champaign


• Richard Blute, University of Ottawa
• Spencer Breiner, NIST
• Daniel Cicala, University of New Haven
• Robin Cockett, University of Calgary
• Bob Coecke, Cambridge Quantum Computing
• Geoffrey Cruttwell, Mount Allison University
• Valeria de Paiva, Samsung Research America and University of Birmingham
• Brendan Fong, Massachusetts Institute of Technology
• Jonas Frey, Carnegie Mellon University
• Tobias Fritz, Perimeter Institute for Theoretical Physics
• Fabrizio Romano Genovese, Statebox
• Helle Hvid Hansen, University of Groningen
• Jules Hedges, University of Strathclyde
• Chris Heunen, University of Edinburgh
• Alex Hoffnung, Bridgewater
• Martti Karvonen, University of Ottawa
• Kohei Kishida, University of Illinois, Urbana -Champaign (chair)
• Martha Lewis, University of Bristol
• Bert Lindenhovius, Johannes Kepler University Linz
• Ben MacAdam, University of Calgary
• Dan Marsden, University of Oxford
• Jade Master, University of California, Riverside
• Joe Moeller, NIST
• Koko Muroya, Kyoto University
• Simona Paoli, University of Leicester
• Daniela Petrisan, Université de Paris, IRIF
• Mehrnoosh Sadrzadeh, University College London
• Peter Selinger, Dalhousie University
• Michael Shulman, University of San Diego
• David Spivak, MIT and Topos Institute
• Joshua Tan, University of Oxford
• Dmitry Vagner
• Jamie Vicary, University of Cambridge
• John van de Wetering, Radboud University Nijmegen
• Vladimir Zamdzhiev, Inria, LORIA, Université de Lorraine
• Maaike Zwart