December 2023 - Categories - categories.org.au

PhD opportunities at the University of Birmingham
by Paul Levy 24 Nov '24

24 Nov '24

* Imminent funding deadline (1 December) - please contact us immediately if you are interested. * Dear all, We invite applications for PhD study at the University of Birmingham. We are a group of (mostly) theoretical computer scientists who explore fundamental concepts in computation. Our work includes category theory, computational complexity, programming language semantics, proof theory, type theory, verification and much else besides. See our webpage, with links to individual researchers, here: https://www.birmingham.ac.uk/research/activity/computer-science/theory-of-c… Information about PhD applications may be found here: https://www.birmingham.ac.uk/schools/computer-science/postgraduate-research… If you are considering applying, please contact any of us. We will be very happy to discuss the opportunities available. Best regards, The Birmingham CS theory group, including:- Benedikt Ahrens Rajesh Chitnis Anupam Das Martín Escardó Eric Finster Dan Ghica Mirco Giacobbe Paul Levy Sonia Marin Sean Moss Jakub Opršal Vincent Rahli Uday Reddy Eike Ritter You're receiving this message because you're a member of the Categories mailing list group from Macquarie University. To take part in this conversation, reply all to this message. View group files<https://outlook.office365.com/owa/categories@mq.edu.au/groupsubscription.as…> | Leave group<https://outlook.office365.com/owa/categories@mq.edu.au/groupsubscription.as…> | Learn more about Microsoft 365 Groups<https://aka.ms/o365g>

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Re: "First" use of 'Category theory' to describe our field
by David Roberts 23 Feb '24

23 Feb '24

Dear Ross, no, that's pretty good! It's mildly surprising that it took ~20 years for the name to 'stick', but maybe less so given that the field grew slowly to start. Thanks, David David Roberts Webpage: https://ncatlab.org/nlab/show/David+Roberts Blog: https://thehighergeometer.wordpress.com On Thu, 11 Jul 2019 at 08:21, Ross Street <ross.street(a)mq.edu.au> wrote: > > Dear David > > From memory, the Pure Mathematics Honours (USyd) course that Max Kelly taught in 1965 > was called ``Category Theory''. It concentrated on different kinds of morphisms > and factorizations in a category, and finished with adjoint functors. > Also John Gray's (UIllinois) 1968-69 graduate course had that name. > > From Eilenberg I heard that each person using categories should have their own category of expertise. > I told this to John Gray who said that was fine; the time had come for that category to be Cat. > > I would suggest that the first category theorists to think of themselves as such were Eilenberg's students at Columbia. > However, Mac Lane was definitely a category theorist. > > This is probably not the verifiable stuff you were seeking. > > Ross > > > On 10 Jul 2019, at 10:01 PM, David Roberts <droberts.65537(a)gmail.com> wrote: > > Hi all, > > the (idle) question is: when did the phrase 'category theory' catch on > for the field? Clearly it didn't leap from either of the heads of > Eilenberg or Mac Lane full-grown, since they used the phrase 'General > theory of natural equivalences'. There are the old 'Reports of the > Midwest Category Seminar' lecture notes (the first in 1967), which > hints that 'category theory' wasn't quite the name in use. > > Even more interesting: who was the first "category theorist", by that name? > > Answers referring to verifiable sources would be best. > > Thoughts? > > David > > > > David Roberts > Webpage: https://ncatlab.org/nlab/show/David+Roberts > Blog: https://thehighergeometer.wordpress.com > [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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History: The Eilenberg-Mac Lane collaboration
by Michael Barr, Prof. 05 Jan '24

05 Jan '24

I would like to tell some of the story of Eilenberg-Mac Lane. I will start with a tale told me my a graduate student at Columbia when I began as an instructor in 1962. He said that Sammy had never met Saunders in person until the International Congress in Cambridge, Mass in 1950 and that after they met, they never collaborated again. It is hard to imagine a more wrong story, but the student appeared to believe it. In fact, Sammy arrived in the US in (I could be off by a year) 1939 and got a one year appointment at U. Michigan. At that time he was working on the (co)homology of K(pi,1). A space with only one non-zero homotopy group pi in dimension n is called a K(pi,n) space. When n =1, pi can be any group. If n > 1, pi has to be commutative. In any case, the (co)homology groups depend only on pi, not on the space. Saunders was working on group extension theory—what we now call exact sequences 0 ---> A --> Pi --> pi --> 1 where A is abelian. He came to Ann Arbor to give a talk on his work and Sammy immediately recognized that they were making the same kinds of computation. In fact they had both discovered H^2(pi,A), which eventually got to be called the second Eilenberg-Mac Lane cohomology group of pi with coefficients in A. (I'm omitting lots of details here.) Anyway, they had a long discussion about this. How could the same computation arise in algebraic topology and (what eventually got to be called) homological algebra. In order to start explaining this they discovered the idea of a natural transformation, for which they needed functors, for which they needed categories. The following year, Sammy went to Indiana U. where he met, among others, Clifford Truesdell, the finest 19th century physicist of the 20th century, which had an interesting consequence, see below. Meantime, the war had started. Saunders moved from being a junior fellow at Harvard to a war office in New York. I'm not sure what they were doing there, but I would speculate they were creating ballistic firing tables. Where to aim a cannon given muzzle speed and wind velocity. But he somehow arranged to have Sammy join the office. Then every night after work, Sammy went to Saunders's apartment and they worked. On categories, on the Eilenberg-Mac Lane cohomology theory and on the the (co)homology of K(pi,n) spaces. The last was doubtless their deepest work. Or any rate, the one I don't really understand. Then the war ended. Sammy stayed in NY, spending the rest of his career at U. Chicago. They spent five years publishing their work from the war years and then their collaboration ceased. Almost surely because they were no longer in the same location. Mail was slow and unsatisfactory and there was no internet. When Charles and I were trying to collaborate on TTT, mail between Montreal and Cleveland took a minimum of two weeks. Then we both got computers and we discovered data transfers and we were off. Of course, collaboration by mail was possible, but highly unsatisfactory. I'm not sure when Bill Lawvere college. Best guess would 1955. He went to Indiana U. and totally impressed Truesdell. In fact, I have heard that he ended up living at the Truesdell's. At that time, he was just as interested in physics as in math. But Truesdell felt that Bill's true calling was math. Although he maintained and interest in physics all his life. At any rate (and I heard this story from Truesdell himself) when he started thinking where Bill should go to study math, he recalled the mathematician who had impressed him the most—Sammy. And that explains how Bill ended up doing his graduate work at Columbia. Michael You're receiving this message because you're a member of the Categories mailing list group from Macquarie University. To take part in this conversation, reply all to this message. View group files<https://outlook.office365.com/owa/categories@mq.edu.au/groupsubscription.as…> | Leave group<https://outlook.office365.com/owa/categories@mq.edu.au/groupsubscription.as…> | Learn more about Microsoft 365 Groups<https://aka.ms/o365g>

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Phil Scott
by Richard Blute 26 Dec '23

26 Dec '23

It is with great sadness that we convey the news to the category theory community that our good friend and colleague Phil Scott passed away this morning (18th December, 2023) after a long battle with cancer. Phil’s many contributions to category theory are well known. Phil and Jim Lambek essentially invented the field of categorical proof theory with a series of papers that culminated in the book “Introduction To Higher-Order Categorical Logic”, which is still the standard text on the subject. Phil’s research went well beyond these initial works: he made major contributions to theoretical computer science, linear logic, inverse semigroup theory and recursion theory. Those of us who knew him personally will always think of him as a mentor, a friend and a genuinely kind soul. Rick Blute Robin Cockett Simon Henry You're receiving this message because you're a member of the Categories mailing list group from Macquarie University. To take part in this conversation, reply all to this message. View group files<https://outlook.office365.com/owa/categories@mq.edu.au/groupsubscription.as…> | Leave group<https://outlook.office365.com/owa/categories@mq.edu.au/groupsubscription.as…> | Learn more about Microsoft 365 Groups<https://aka.ms/o365g>

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Category Theory as an educational tool in The Guardian / Observer
by Bob Coecke 26 Dec '23

26 Dec '23

Hi all, We would like to point to an article in the Guardian / Observer earlier this week that was about the educational benefits of category theory, as compellingly demonstrated by an experiment that we just did: https://www.theguardian.com/science/2023/dec/16/physicist-bob-coecke-its-ea… The word “category theory” only occurs twice, but it all concerns monoidal string diagrams, with structures like dagger compact closure and dagger Frobenius algebras. Concretely, what we did was teach 60 fairly averagely chosen 15-17 yr old secondary school students categorical quantum mechanics using the book “Quantum in Pictures” by Stefano Gogioso and myself. The only maths pre-requisite for that book is knowing how angles add up. We have video lectures of the book that we will release soon, and also recorded some worked-out exercises that we also will release soonish. With these resources we created an on-line course that follows the template of a typical Oxford post-grad course, but without the benefits of in person teaching. We then subjected the students to an exam exclusively consisting of Oxford post-grad quantum exam questions. The result: 80% passed and almost 40% got distinctions. Here is a statement by Oxford Uni about the experiment: https://www.cs.ox.ac.uk/news/2280-full.html and here is an extensive blog post I wrote about it, providing some additional context: https://medium.com/quantinuum/everyone-can-learn-quantum-now-even-at-a-cutt… All our best wishes for the new year! You're receiving this message because you're a member of the Categories mailing list group from Macquarie University. To take part in this conversation, reply all to this message. View group files<https://outlook.office365.com/owa/categories@mq.edu.au/groupsubscription.as…> | Leave group<https://outlook.office365.com/owa/categories@mq.edu.au/groupsubscription.as…> | Learn more about Microsoft 365 Groups<https://aka.ms/o365g>

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LICS 2024 Second Call for Papers
by Sam Staton 22 Dec '23

22 Dec '23

SECOND CALL FOR PAPERS Thirty-Ninth Annual ACM/IEEE Symposium on LOGIC IN COMPUTER SCIENCE (LICS) Tallinn, July 2024 https://lics.siglog.org/lics24 SCOPE The LICS Symposium is an annual international forum on theoretical and practical topics in computer science that relate to logic, broadly construed. We invite submissions on topics that fit under that rubric. Suggested, but not exclusive, topics of interest include: automata theory, automated deduction, categorical models and logics, concurrency and distributed computation, constraint programming, constructive mathematics, database theory, decision procedures, description logics, domain theory, finite model theory, formal aspects of program analysis, formal methods, foundations of computability, foundations of probabilistic, real-time and hybrid systems, games and logic, higher-order logic, knowledge representation and reasoning, lambda and combinatory calculi, linear logic, logic programming, logical aspects of AI, logical aspects of bioinformatics, logical aspects of computational complexity, logical aspects of quantum computation, logical frameworks, logics of programs, modal and temporal logics, model checking, process calculi, programming language semantics, proof theory, reasoning about security and privacy, rewriting, type systems, type theory, and verification. IMPORTANT DATES FOR PAPERS Authors are required to submit a paper title and a short abstract of about 100 words in advance of submitting the extended abstract of the paper. The exact deadline time on these dates is anywhere on earth (AoE). Titles and Short Abstracts Due: 21 January 2024 Full Papers Due: 26 January 2024 Author Feedback/Rebuttal Period: 18-23 March 2024 Author Notification: 15 April 2024 Conference: 8-12 July 2024. Submission deadlines are firm; late submissions will not be considered. All submissions will be electronic via easychair. PAPER SUBMISSION INSTRUCTIONS Submissions should use ACM SIGCONF Proceedings 2-column 10pt format and may be at most 12 pages, excluding references. Latex style files and further submission information is at https://lics.siglog.org/lics24/cfp.php. LICS 2024 will use a lightweight double-blind reviewing process. Please see the website for further details and requirements from the double-blind process. The official publication date may differ from the first day of the conference. The official publication date may affect the deadline for any patent filings related to published work. We will clarify the official publication date in due course. You're receiving this message because you're a member of the Categories mailing list group from Macquarie University. To take part in this conversation, reply all to this message. View group files<https://outlook.office365.com/owa/categories@mq.edu.au/groupsubscription.as…> | Leave group<https://outlook.office365.com/owa/categories@mq.edu.au/groupsubscription.as…> | Learn more about Microsoft 365 Groups<https://aka.ms/o365g>

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Modification of what I said
by Michael Barr, Prof. 21 Dec '23

21 Dec '23

Peter Freyd claims that Hassler Whitney defined natural transformation in a 1938 paper. I no longer have access to Math. Reviews (except by going to McGill, which I have done only once in the last four years) so I cannot supply a reference. Michael You're receiving this message because you're a member of the Categories mailing list group from Macquarie University. To take part in this conversation, reply all to this message. View group files<https://outlook.office365.com/owa/categories@mq.edu.au/groupsubscription.as…> | Leave group<https://outlook.office365.com/owa/categories@mq.edu.au/groupsubscription.as…> | Learn more about Microsoft 365 Groups<https://aka.ms/o365g>

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17th International Workshop on Coalgebraic Methods in Computer Science (CMCS'24): Second Call for Papers
by Henning Urbat 20 Dec '23

20 Dec '23

SECOND CALL FOR PAPERS ===================== The 17th IFIP WG 1.3 International Workshop on Coalgebraic Methods in Computer Science (CMCS'24) Luxembourg, 6-7 April 2024 (co-located with ETAPS 2024) https://www.coalg.org/cmcs24/ Objectives and scope -------------------- Established in 1998, the CMCS workshops aim to bring together researchers with a common interest in the theory of coalgebras, their logics, and their applications. As the workshop series strives to maintain breadth in its scope, areas of interest include neighbouring fields as well. Topics of interest are the theory and applications of coalgebra and coinductive reasoning in all research areas of Computer Science, including (but not limited to) the following: - set-theoretic and categorical foundations of coalgebra; - algebra & coalgebra, (co)monads, and distributive laws; - (modal) logic; - automata theory and formal languages; - coinductive definitions and proof principles (including "up-to" techniques) - semantic models of computation (for programming languages, dynamical systems, term rewriting, etc.) - functional, objected-oriented, concurrent, and constraint programming; - type theory (notably behavioural typing); - formal verification and specification; - control theory (notably discrete events and hybrid systems); - quantum computing; - game theory; - implementation, tools, and proof assistants In addition to presentations of contributed papers, the workshop will also include invited talks and tutorials. Venue and event --------------- CMCS '24 will be held in Luxembourg City, Luxembourg, co-located with ETAPS 2024 on 6-7 April 2024. Important dates (tentative) --------------------------- Abstract regular papers 29 January 2024 Submission regular papers 2 February 2024 Notification regular papers 5 March 2024 Final version 25 March 2024 Submission short contributions 7 March 2024 Notification short contributions 11 March 2024 Programme committee ------------------- Adriana Balan (University Politehnica of Bucharest, Romania) Harsh Beohar (University of Sheffield, United Kingdom) Marta Bilkova (Academy of Sciences of the Czech Republic) Fredrik Dahlqvist (Queen Mary University of London, United Kingdom) Jérémy Dubut (National Institute of Advanced Industrial Science and Technology, Japan) Sebastian Enqvist (Lund University, Sweden) Richard Garner (Macquarie University, Australia) Ichiro Hasuo (National Institute of Informatics, Japan) Tobias Kappé (Open University of the Netherlands and ILLC, University of Amsterdam) Marina Lenisa (University of Udine, Italy) Larry Moss (Indiana University Bloomington, United States) Fredrik Nordvall Forsberg (University of Strathclyde, United Kingdom) Jurriaan Rot (Radboud University, The Netherlands) Matteo Sammartino (Royal Holloway University of London, United Kingdom) Pawel Sobocinski (Tallinn University of Technology, Estonia) David Spivak (Topos Institute, United States) Sam Staton (University of Oxford, United Kingdom) Tarmo Uustalu (Reykjavik University, Iceland, and Tallinn University of Technology, Estonia) Thorsten Wißmann (Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany) PC co-chairs -------------- Barbara König (Universität Duisburg-Essen, Germany) Henning Urbat (Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany) Publicity chair --------------- Thorsten Wißmann (Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany) Steering committee ------------------ Corina Cirstea, University of Southampton, United Kingdom Helle Hansen, University of Groningen, The Netherlands Ichiro Hasuo, National Institute of Informatics, Japan Bart Jacobs, Radboud University Nijmegen, The Netherlands Stefan Milius, Friedrich-Alexander Universität Erlangen-Nürnberg, Germany Daniela Petrişan, IRIF, Université Paris-Cité, France Jurriaan Rot, Radboud University Nijmegen, The Netherlands Lutz Schröder, Friedrich-Alexander Universität Erlangen-Nürnberg, Germany Alexandra Silva (chair), Cornell University, United States Fabio Zanasi (University College London, United Kingdom Submission guidelines --------------------- We solicit two types of contributions: regular papers and short contributions. Regular papers must be original, unpublished, and not submitted for publication elsewhere. Regular papers should be at most 18 pages long in Springer LNCS style, excluding references. A clearly marked appendix containing technical proofs can be added, but this will not be published in the proceedings. Note that the reviewers are not obliged to read the appendix, and the merits of the paper should be clear from the main text. Short contributions may describe work in progress, or summarise work submitted to a conference or workshop elsewhere. They should be no more than two pages including references. Regular papers and short contributions must be submitted electronically as a PDF file via the Easychair system at https://easychair.org/my/conference?conf=cmcs2024 The proceedings of CMCS 2024 will include all accepted regular papers and will be published post-conference as a Springer volume in the IFIP-LNCS series. Accepted short contributions will be bundled in a technical report. 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Looking for Jean-Louis Loday's slides on "Combinads"
by Chaitanya Leena Subramaniam 19 Dec '23

19 Dec '23

Hello all, I notice that Jean-Louis Loday's personal web page (https://irma-web1.math.unistra.fr/~loday/) is not accessible any more. It used to have slides from a talk that Loday gave in 2012 on "combinads". The link to these slides was https://irma-web1.math.unistra.fr/~loday/PAPERS/A-O-C%28Lille2012%29.pdf I can access a snapshot of Loday's web page on the Internet Archive but it seems that there is no snapshot of the slides of this talk. I used to have a PDF of these slides, but I can't find it any more. Would anyone on this mailing list have a copy of them? Best, Chaitanya You're receiving this message because you're a member of the Categories mailing list group from Macquarie University. To take part in this conversation, reply all to this message. View group files<https://outlook.office365.com/owa/categories@mq.edu.au/groupsubscription.as…> | Leave group<https://outlook.office365.com/owa/categories@mq.edu.au/groupsubscription.as…> | Learn more about Microsoft 365 Groups<https://aka.ms/o365g>

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HoTT/UF 2024: Second Call for Contributions and Participation
by Jonathan Weinberger 19 Dec '23

19 Dec '23

========================================================= 2ND CALL FOR CONTRIBUTIONS AND PARTICIPATION Workshop on Homotopy Type Theory and Univalent Foundations (HoTT/UF 2024, co-located with WG6 meeting of the EuroProofNet COST action) ========================================================== ------------------------------------------------------------------------ Workshop on Homotopy Type Theory and Univalent Foundations April 2 - 3, 2024, Leuven, Belgium https://hott-uf.github.io/2024/ Co-located with the WG6 meeting of the EuroProofNet COST action April 4 - 5, 2024 https://europroofnet.github.io/wg6-leuven/ ------------------------------------------------------------------------ Homotopy Type Theory is a young area of logic, combining ideas from several established fields: the use of dependent type theory as a foundation for mathematics, inspired by ideas and tools from abstract homotopy theory. Univalent Foundations are foundations of mathematics based on the homotopical interpretation of type theory. The goal of this workshop is to bring together researchers interested in all aspects of Homotopy Type Theory/Univalent Foundations: from the study of syntax and semantics of type theory to practical formalization in proof assistants based on univalent type theory. The workshop will be held in person with support for remote participation. We encourage online participation for those who do not wish to or cannot travel. ================ # Invited speakers * Rafaël Bocquet (Eötvös Loránd University, Hungary) * Matthias Hutzler (University of Gothenburg, Sweden) * TBA ================ # Submissions * Abstract submission deadline: January 19, 2024 * Author notification: Mid-February 2024 Submissions should consist of a title and a 1-2 pages abstract, in pdf format, via https://easychair.org/conferences/?conf=hottuf2024. Considering the broad background of the expected audience, we encourage authors to include information of pedagogical value in their abstract, such as motivation and context of their work. ================ # Registration Registration is mandatory with a deadline of 8 March 2024 (AoE). Registration information will be provided shortly. ================ # Program committee * Pierre Cagne (Applachian State University) * Evan Cavallo (University of Gothenburg) * Felix Cherubini (Chalmers University of Technology/University of Gothenburg) * Tom de Jong (University of Nottingham) * Eric Finster (University of Birmingham) * Daniel Gratzer (Aarhus University) * Mitchell Riley (NYU Abu Dhabi) * Michael Shulman (University of San Diego) * Kristina Sojakova (INRIA Paris) * Jon Sterling (University of Cambridge) * Andrew Swan (University of Ljubljana) * Jonathan Weinberger (Johns Hopkins University) ================ # Organizers * Evan Cavallo, evan.cavallo(a)gu.se<mailto:evan.cavallo@gu.se> (University of Gothenburg) * Tom de Jong, tom.dejong(a)nottingham.ac.uk<mailto:tom.dejong@nottingham.ac.uk> (University of Nottingham) * Mitchell Riley, mitchell.v.riley(a)nyu.edu<mailto:mitchell.v.riley@nyu.edu> (NYU Abu Dhabi) * Jonathan Weinberger, jweinb20(a)jhu.edu<mailto:jweinb20@jhu.edu> (Johns Hopkins University) You're receiving this message because you're a member of the Categories mailing list group from Macquarie University. To take part in this conversation, reply all to this message. View group files<https://outlook.office365.com/owa/categories@mq.edu.au/groupsubscription.as…> | Leave group<https://outlook.office365.com/owa/categories@mq.edu.au/groupsubscription.as…> | Learn more about Microsoft 365 Groups<https://aka.ms/o365g>

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