September 2026 - Categories - categories.org.au

Winter School: Homotopical Methods in Geometry and Representation Theory — Prague, 15–19 February 2027
by FERNANDO MURO JIMENEZ 19 Sep '26

19 Sep '26

Dear colleagues, We would like to announce the winter school Homotopical Methods in Geometry and Representation Theory which will take place at the Institute of Mathematics of the Czech Academy of Sciences in Prague, on 15–19 February 2027. The school aims to introduce participants to methods from homotopy theory that have recently found applications in geometry and representation theory. The programme will consist of five lecture series covering topics including: - differential graded and A-infinity categories and enhancements of triangulated categories, - model categories and the Kan–Quillen model structure, - spectral sequences, - differential graded operads and their homotopy theory, - obstruction theory for A-infinity algebras and bimodules. Speakers: Gustavo Jasso, Fernando Muro, Constanze Roitzheim, Paolo Stellari, and Sarah Whitehouse. Further information and registration can be found at: https://sites.google.com/view/hmgrt/ The registration deadline is 31 December 2026. A limited amount of financial support is available to cover accommodation costs for early-career researchers. Applications for financial support should be submitted through the registration form by 30 November 2026. Please feel free to circulate this announcement among potentially interested colleagues and students. Best regards, The organisers Michal Hrbek Gustavo Jasso Fernando Muro Jan Šťovíček Alexandra Zvonareva Fernando Muro Universidad de Sevilla, Departamento de Álgebra https://personal.us.es/fmuro/

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2nd Announcement: QCOMICAL School 2026 on Quantum Programming Languages and Semantics
by tedeschi 15 Sep '26

15 Sep '26

Apologies for multiple copies. ========================================================== QCOMICAL School 2026 16-20 November 2026, Pisa, Italy https://qcomical2026.github.io ========================================================== BACKGROUND: After a succesfull first edition in Nancy (France), the second QCOMICAL School will take place in Pisa (Italy) as part of the QCOMICAL project. The school will offer tutorials and lectures by leading researchers involved in the project, working on quantum computing with a focus on quantum programming languages and their semantics, fostering interaction across foundational approaches. COURSES: • Computational Quantum Logic - Alejandro Díaz-Caro (Inria Nancy, France & Universidad de la República, Uruguay) • Bayesian Networks (and Quantum Ones) - Claudia Faggian (CNRS/Université Paris Cité, France) • Quantum Process Calculi - Fabio Gadducci (CINI/Università di Pisa, Italia) • Tool Session: Automated Verification of Quantum Protocols - Giuseppe Lomurno (Università di Pisa, Italy) • Quantum Programming Languages - Benoît Valiron (CentraleSupélec, France) • Categories for Quantum Computing - Vladimir Zamdzhiev (INRIA/Université Paris Saclay, France) REGISTRATION: * Opens now, up until October 16. * Free of charge. * Coffee breaks and lunches are included. Travel and accommodation are at participants' expense. * The registration form and practical details (travel, visas, accommodation) are in the website. ORGANISING COMMITTEE: • Roberto Bruni - Università di Pisa, Italia • Alejandro Dìaz-Caro - Inria Nancy, France & Universidad de la República, Uruguay • Fabio Gadducci (chair) - CINI/Università di Pisa, Italia • Gabriele Tedeschi - Université Paris Cité/CNRS, France • Benoît Valiron - CentraleSupélec, France FUNDING: The QComical project is funded by the European Union through the Marie Skłodowska-Curie Actions – Staff Exchanges programme (MSCA-SE). Current sponsors are AICA, Alice&Bob, Università di Pisa.

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NWPT 2026, Final Call for Contributions
by Chad Mitchell Nester 15 Sep '26

15 Sep '26

== Call for Papers == 36th Nordic Workshop on Programming Theory November 19-20th, 2026, University of Tartu, Tartu, Estonia Conference web page: https://kodu.ut.ee/~nester/nwpt-2026/main.html == Important Dates (AOE) == * Submission of Abstracts: October 5th, 2026, 23:59 AOE * Notification: October 30th, 2026 * Submission of Final Version of Abstracts: November 6th, 23:59 AOE * Registration Deadline: November 2nd, 2026, 23:59 AOE * Conference Dates: November 19-20th, 2026 == Scope == NWPT is a series of annual regional-scope workshops on programming theory, targeted especially at younger researchers. In 2026, the workshop will take place in Tartu, Estonia. We hope this will be a nice opportunity to present recent results and/or work-in-progress, and to meet colleagues from the Nordic and Baltic countries. We encourage PhD students and postdocs to contribute. Topics of interest include (but are not limited to): * semantics of programming languages * programming language design and programming methodology * programming logics * formal specification of programs * program verification * program construction * tools for program verification and construction * program transformation and refinement * real-time, hybrid/cyber-physical systems modeling and verification * models of concurrency and distributed computing * model checking * model-based testing * language-based security == Submission Guidelines == Authors wishing to give a talk at the workshop are requested to submit abstracts of 2-3 pages (pdf, printable on A4 paper, typeset with LaTeX with easychair.cls) through EasyChair by October 5th: https://easychair.org/my/conference?conf=nwpt2026 Work in progress as well as abstracts of manuscripts submitted for formal publication elsewhere are permitted. The abstracts of the accepted contributions will be available electronically before the workshop. By submitting to EasyChair you agree that your abstract will be publicly available. Moreover, you as an author are responsible for the content. As in earlier NWPT workshops, we plan to arrange a special issue of the Journal of Logical and Algebraic Methods in Programming (JLAMP) devoted to the best contributions to the workshop. The contributions will be selected by the PC. They will be invited after the workshop and will undergo a rigorous, journal-strength review process according to the standards of JLAMP. This year submissions from NWPT 2023 and NWPT 2024 will be considered as well. == Program Committee == * Aggeliki Chalki, Reykjavik University, Iceland * Alceste Scalas, Technical University of Denmark, Denmark * Cheng-Syuan Wan, Tallinn University of Technology, Estonia * Daniel Gratzer, Aarhus University, Denmark * Elias Castegren, Uppsala University, Sweden * Elli Anastasiadi, Aalborg University, Denmark * Evan Cavallo, University of Gothenburg, Sweden * Fritz Henglein, University of Copenhagen, Denmark * Jaakko Jarvi, University of Turku, Finland * Keijo Heljanko, University of Helsinki, Finland * Lizeth Tapia, University of Oslo, Norway * Maja Hanne Kirkeby, Roskilde University, Denmark * Marina Walden, Åbo Akademi University, Finland * Marjan Sirjani, Mälardalen University, Sweden * Matthew Earnshaw, University of Tartu, Estonia * Mikhail Barash, University of Bergen, Norway * Peter LeFanu Lumsdaine, Stockholm University, Sweden * Rasmus Møgelberg, IT University of Copenhagen, Denmark * Robin Kaarsgaard, University of Southern Denmark, Denmark * Violet Ka I Pun, Western Norway University of Applied Sciences, Norway == Organisers and PC Chairs == * Chad Nester, University of Tartu, Estonia * Matthew Earnshaw, University of Tartu, Estonia == Contact == Please direct any questions to nester(a)ut.ee

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RHPL@FSTTCS 2026: Second Call for Proposals
by Abhisekh Sankaran 15 Sep '26

15 Sep '26

TCS Confidential ============================================================= CALL FOR PROPOSALS RHPL@FSTTCS 2026: Workshop on Research Highlights in Programming Languages + Dates: December 16 - 18, 2026 + Venue: IIT Delhi, co-located with FSTTCS 2026 + Website: https://fmindia.cmi.ac.in/rhpl2026/ + Submission link: https://forms.fillout.com/t/7ePHh773f2us + Submission deadline: September 28, 2026 IST ============================================================= Dear Colleague, As you may know, FSTTCS 2026 (https://www.fsttcs.org.in/2026/) will be held at IIT Delhi (https://home.iitd.ac.in/) during December 16 - 18, 2026. The conference is organized by IARCS, the Indian Association for Research in Computing Science (https://www.iarcs.org.in/) in association with ACM India (https://india.acm.org/) It is a very visible forum for presenting original results in foundational aspects of computer science and software technology. As in previous years, the Workshop on Research Highlights in Programming Languages (RHPL) will be co-located with the main FSTTCS conference. The focus of the workshop will be on all areas of programming languages. The workshop is organized jointly this year by IARCS and iPLAN (the India Chapter of ACM SIGPLAN; https://india.acm.org/chapters) The objective of RHPL is to foster interactions between researchers working on programming languages and the traditional FSTTCS community of researchers working on theoretical computer science and formal methods. We invite proposals for: + Talks: based on recent work that has been published in reputed venues, or is mature in terms of approach and evaluation. + Posters: - Regular: Based on early ideas that are promising but have not been developed fully. Selections of these proposals will be made based on the promise of research possibilities and their novelty. - Student: Based on unpublished work at any stage. Selected proposals will be included in a Student Poster Competition that will be judged by a panel of experts. More details on the submission topics, submission guidelines and the poster competition can be found below. --------------- Websites: --------------- RHPL 2026: https://fmindia.cmi.ac.in/rhpl2026/ RHPL 2025: https://fmindia.cmi.ac.in/rhpl2025/ ============= Important Dates ============= All dates below are in Indian Standard Time (IST). - Submission portal opens: August 21, 2026 - Submission deadline: September 28, 2026 - Notification: October 7, 2026 - Early registration deadline: TBA - RHPL@FSTTCS: December 16 - 18, 2026 =============== Submission Topics =============== The submission topics include, but are not limited to, the following: - Applied formal methods - Automated and interactive theorem provers - Compilers - Concurrency and memory models - Domain and type theories - Program analysis and verification - Program sketching, synthesis, and repair - Programming language design and semantics Further, in view of the increasing role of Artificial Intelligence (AI) and Machine Learning (ML) in PL theory and practice, the workshop explicitly includes in its scope themes at this intersection. Of particular interest are the roles of Large Language Models (LLMs) in PL, such as in design and code synthesis, as well as broader mutual influences between AI/ML and PL; for instance, probabilistic programming languages. ==================== Student Poster Competition ==================== We invite students at all stages, from undergraduate to PhD, to submit poster proposals based on their unpublished work. For graduate students, only individual work is allowed to be presented. If the work is being done as part of a group, then the presenters must focus on their individual contributions. Undergraduates can present their individual work and also work done in (undergraduate) team projects. The evaluation of the posters will be on the basis of the technical strength of the work, the presenter's awareness of related literature, and the quality of the poster and presentation. The results will be announced on the RHPL 2026 website following the competition. ================ Submission Guidelines ================ Proposals to the workshop may be submitted using the form below. https://forms.fillout.com/t/7ePHh773f2us Proposals for talks may be based on published or unpublished work. Proposals for posters are only for unpublished work. For both formats, submissions may present either a single study, such as in an individual paper or an unpublished manuscript, or a body of research. Multiple proposal submissions are allowed. Each proposal must be submitted as a single PDF file. Any reasonable style file can be chosen. The proposal page limits are as below; the page counts exclude references. Appendices are to be avoided, and references may contain pointers to papers, preprints, technical reports, or manuscripts under progress that the proposal is based on. + Talks: - Proposals based on work that is published: 2 pages - Proposals based solely on unpublished work: 4 pages + Posters: - Regular (non-student) proposals: 2 pages - Student proposals: 4 pages Talk proposals based on unpublished work and student poster proposals will be provided short referee reports along with their decision notifications. There are no publications of the workshop. Accepted proposals may be compiled into a booklet of abstracts/proposals to be made available on the RHPL 2026 website. ======= Contact ======= For any queries, feel free to write to us at the email addresses below. - pankaj.kumar.kalita(a)ibm.com<mailto:pankaj.kumar.kalita@ibm.com> - abhisekh.sankaran(a)tcs.com<mailto:abhisekh.sankaran@tcs.com> We look forward to receiving your talk/poster proposals to the workshop. On behalf of the RHPL@FSTTCS workshop organizing committee: Pankaj Kumar Kalita (IBM Research) (co-Chair) Abhisekh Sankaran (TCS Research) (co-Chair) Deepak D'Souza (IISc Bangalore) Uday Khedker (IIT Bombay) Kumar Madhukar (IIT Delhi) Kartik Nagar (IIT Madras) Ganesan Ramalingam (Microsoft) Abhik Roychoudhury (National University of Singapore) Divyesh Unadkat (Synopsys) =====-----=====-----===== Notice: The information contained in this e-mail message and/or attachments to it may contain confidential or privileged information. If you are not the intended recipient, any dissemination, use, review, distribution, printing or copying of the information contained in this e-mail message and/or attachments to it are strictly prohibited. If you have received this communication in error, please notify us by reply e-mail or telephone and immediately and permanently delete the message and any attachments. Thank you

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First meeting of Tallinn–Tartu category theory seminar (KASS), 9th October
by Matt Earnshaw 11 Sep '26

11 Sep '26

Dear all, The first meeting of the Tallinn–Tartu category theory seminar <https://tetrapharmakon.github.io/kass/> (KASS) will take place in Tallinn on 9th October 2026. Modelled on other regional CT seminars, KASS seeks to draw together the community of researchers and students across the Department of Software Science at Tallinn University of Technology, and the Institutes of Computer Science and Mathematics at the University of Tartu, as well as participants from the wider locality beyond. Meetings will alternate between Tallinn and Tartu, and will combine research talks with informal discussion, including work in progress. All are welcome, and we particularly encourage PhD students to present their work. A tentative programme may be found on the website <https://tetrapharmakon.github.io/kass/>. Best regards, The Organizers

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Algebra Down Under 2026, the 10th Australian Algebra Conference (16-20 Nov 2026)
by JS Lemay 11 Sep '26

11 Sep '26

[[Send on behalf of the organisers]] Dear colleagues, We are pleased to announce Algebra Down Under 2026, the 10th Australian Algebra Conference, which will be held at Western Sydney University in Sydney, Australia, from 16–20 November 2026. The conference will bring together mathematicians working across a broad range of areas in algebra, including category theory, representation theory, K-theory, universal algebra, operator algebras, noncommutative algebra, group theory, algebraic geometry, semigroup theory, graph theory, and coding theory. Registration is now open through the conference website: https://adu2027.github.io/10thaac/ Early-bird registration closes on 30 September 2026. The early-bird fees are AUD 180 for academics and general participants, and AUD 100 for students, postdoctoral researchers, and early-career researchers. The submission link for contributed talks will be available shortly on the conference website. Talk submissions and conference registration will be handled separately, so those interested in presenting a talk are welcome to register now. Further information, including the list of invited speakers, is available on the conference website. Questions may be directed to adu(a)westernsydney.edu.au<mailto:adu@westernsydney.edu.au>. We would be grateful if you could share this announcement with interested colleagues and students. Best wishes, The Algebra Down Under 2026 Organising Committee

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Mini-course on tangent categories at the University of Strathclyde 13--16 October
by Fredrik Nordvall Forsberg 08 Sep '26

08 Sep '26

Dear all, Geoffrey Cruttwell will be coming to the University of Strathclyde, Glasgow, Scotland to give a 6 x 1 hour tutorial on tangent categories 13 to 16 October 2026, more precisely the following dates: Tuesday 13 October Wednesday 14 October Friday 16 October Neil Ghani will also give a 6 x 1 hour lecture series on containers/polynomial functors. The courses will take place in Livingstone Tower, which is part of the University of Strathclyde's campus in Glasgow City Centre. For more information, see https://msp.cis.strath.ac.uk/tangentcats-2026/ . Attendance is free, but please register here for planning purposes: https://forms.cloud.microsoft/e/BFugK7iUqY . Registration deadline: Monday 5 October 2026. Best wishes, and hope to see you there, Fred # Abstracts ## Tangent categories tutorial (Geoffrey Cruttwell, Mount Allison University) Tangent categories are a "minimal" categorical setting for differential geometry. Previous work on categorical machine learning has used cartesian differential categories (and variants of it), but that abstraction is not flexible enough to work with learning on manifolds. Tangent categories enable one to "do differential geometry" on manifolds and many other settings, and thus represent the "next step" for the study of categorical machine learning. In this tutorial I'll introduce what tangent categories are, give a variety of models for their axioms, and show some of their theory. Basic category theory knowledge is assumed, but I will not assume any knowledge of differential geometry or categorical machine learning. ## Containers: Theory and Applications (Neil Ghani, Kodamai) A container is a strikingly simple idea: a set of prompts, and for each prompt a set of admissible responses. From this modest starting point comes an enormous range of structure — every ordinary data type arises as the least fixed point of a container, and the functors they denote, the polynomial functors, sit at the heart of type theory, category theory, and functional programming. A container is at once a data type and a typed interface, specifying for every prompt exactly which responses are valid, and it carries a rich algebra: several monoidal structures, a well-behaved notion of morphism, closed structure, and a derivative. This series introduces containers from the ground up, and then follows them into computer science. We cover the basic theory — the definition and its readings, the extension to polynomial functors, container morphisms, the monoidal and closed structures, free and cofree containers, monads over containers, and indexed and directed containers — before turning to applications: machine learning, agentic AI, theorem proving, and differential algebra.

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October/Novemberfest 2026 First Announcement
by Richard Blute 04 Sep '26

04 Sep '26

The 2026 Category Theory October/Novemberfest will be held on the weekend of October 31st through November 1st. The meeting will be virtual. (Links will be provided soon.) Following the tradition of past Octoberfests, this is intended to be an informal meeting, covering all areas of category theory and its applications. Talks by PhD students and young researchers are particularly encouraged! If interested in speaking, please send title and abstract to Rick Blute at rblute(a)uottawa.ca<mailto:rblute@uottawa.ca> by October 15th.

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Pacific Category Theory Seminar (Online) - Friday, September 11
by Soichiro Fujii 04 Sep '26

04 Sep '26

Dear all, Yuki Maehara (Tokyo Metropolitan University) will give a talk for this month's PCT seminar (https://pctseminar.github.io/) on Friday September 11 at 10am JST/11am AEST (1am UTC). The zoom link to join the seminar is: https://kyoto-u-edu.zoom.us/j/82401794000?pwd=VjVmzVjmlgxhkdHES4xYeQBTpMzQk… Title: Towards a homotopy theory of algebraic weak ω-categories Abstract: Mainstream models of weak infinite-dimensional categories (such as quasi-categories or complicial sets) are based on certain non-globular shapes (such as simplices). This allows one to encode the desired category-like *structure* as an existence *property*. For example, composition of 1-cells can be encoded as "for any composable pair f and g, there exists a triangle two of whose edges are f and g", and such a triangle exhibits the third edge as a composite of f and g. We don't require this triangle to be unique for given f and g, so composition is not well defined on the nose. This makes it impossible even to state strict axioms, and hence the resulting model is necessarily weak. But it is not too weak — composition is still "essentially" unique, satisfies the unit and associativity laws "up to equivalence", and so on — thanks to similar existence properties of higher-dimensional shapes. What happens if we instead use the familiar globes so that, for example, the boundary of a 2-cell is given by a parallel pair of 1-cells rather than a triangle? Well, the 2-globe (or in fact the n-globe for any n) doesn't contain a composable pair of 1-cells, so now we must encode composition as an actual algebraic operation rather than as an existence property; this is what "algebraic" means in the title of this talk. I will give an overview of a joint project with Soichiro Fujii and Keisuke Hoshino on such algebraic weak ω-categories, namely those of Batanin and Leinster, which are the Eilenberg–Moore algebras for a suitable monad on the category of globular sets. Compared with the mainstream models (formulated in the language of model categories or ∞-categories), this definition has the downside that it does not naturally come equipped with a homotopy theory, which makes it difficult to capture up-to-equivalence phenomena and constructions. On the other hand, it has the upside that these algebraic weak ω-categories feel much closer to strict ω-categories, particularly because not only the shapes of the cells but also the algebraic structure is designed to mirror the familiar behaviour of their strict counterparts. The overarching theme of this project is therefore to develop a suitable homotopy theory of algebraic weak ω-categories, drawing on the strict case for as much intuition — and even proof strategies — as possible. We hope to see you there! Talks are posted on YouTube afterwards: https://www.youtube.com/@PCTSeminar Best wishes, Soichiro Fujii, Zeinab Galal, JS Lemay

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Yang-Baxter Equation in Group Theory, Category Theory and Noncommutative Geometry: first announcement and call for contributions
by Yang-Baxter Equation in Group Theory Category Theory and Noncommutative Geometry 03 Sep '26

03 Sep '26

Dear friends and colleagues, We are glad to announce the "Yang-Baxter Equation in Group Theory, Category Theory and Noncommutative Geometry" conference that will be held at the Będlewo conference center from the 5th to the 9th of April, 2027. Please, feel free to share the details of this event in your local academic community and to forward the information to anyone who might be interested. ============================== *Yang-Baxter Equation in Group Theory, Category Theory and Noncommutative Geometry* *When*: 5-9 April 2027 *Where*: Będlewo conference center, Będlewo, Poland ============================== *Confirmed speakers* - Edwin Beggs - Swansea University, UK - Andrzej Borowiec - University of Wroclaw, Poland - Gabriella Böhm - EMS Press, Berlin, Germany - Rinat Kashaev - University of Geneva, Switzerland - Ganna Kudryavtseva - University of Ljubljana, Slovenia - Réamonn Ó Buachalla - Charles University, Czech Republic - Karen Strung - Czech Academy of Sciences, Czech Republic - Magdalena Wiertel - University of Warsaw, Poland ============================== *Conference Fee* The conference fee is 500 EUR, which covers the accommodation on site and full board from April 04 dinner till April 10 breakfast. ============================== *Registration* We invite applications for contributed talks, which will be scheduled for 25 minutes plus an additional 5 minutes for questions. The deadline for submitting abstracts is March 5. Please note that due to a limited number of slots, we cannot guarantee acceptance of all applications. To register, please fill out the registration form here. ============================== *Practical information* Participants are expected to arrive on Sunday, April 04, and depart on Saturday, April 09. Check-in for your accommodation will start at 2:00 PM on Sunday, April 04, at the conference centre. Check-out is required by 11:00 AM on Saturday, April 09. Participants who are self-funding their attendance are kindly requested to submit their affiliation details along with their registration payment. This information is essential for accurate identification of the source of the bank transfer and proper invoice preparation. Should you require any further information regarding registration or accommodation, please do not hesitate to contact us at yangbaxter(a)impan.pl. ============================== For more information, please visit our conference webpage https://sites.google.com/impan.pl/yangbaxter. If you have any questions, feel free to contact us at yangbaxter(a)impan.pl. We are looking forward to seeing you in Będlewo! Best regards, Tomasz Brzeziński Ilaria Colazzo Paolo Saracco Leandro Vendramin

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