November 2020 - Categories - categories.org.au

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

24 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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Re: Invitation: GReTA online seminar, December 4 at 15:00 CET
by Heckel, Reiko (Prof.) 30 Nov '20

30 Nov '20

CAUTION: The Sender of this email is not from within Dalhousie. FYI, the second one in our new series. Looking forward to see you all on Friday! Reiko On 30/11/2020, 08:42, "GReTA Seminar organisers" <greta(a)irif.fr> wrote: Dear colleagues, It is our great pleasure to invite you to the second seminar of the “GReTA - Graph Transformation Theory and Applications” series: Friday, December 4, 15:00 CET “Chemical Graph Transformation and Applications”, J.L. Andersen and D. Merkle (abstract: see attached) Please refer to http://www.irif.fr/~greta<https://eur03.safelinks.protection.outlook.com/?url=http:%2F%2Fwww.irif.fr%…> for further information on how to register for this Zoom meeting, or alternatively on how to attend the meeting via a YouTube live stream! The GReTA seminar series aims to serve as a platform for the international graph rewriting community, to promote recent developments and trends in the field, and to permit a regular networking and interaction between members of this community. Seminars are scheduled twice a month (cf. https://www.irif.fr/~greta/#talks<https://eur03.safelinks.protection.outlook.com/?url=https:%2F%2Fwww.irif.fr…> for a list of upcoming events). With best regards, Nicolas Behr, Jean Krivine and Reiko Heckel (GReTA organisers) ___________________________________________________ Date and time: Friday, December 4, 15:00 CET Speaker: J.L. Andersen and D. Merkle Title: Chemical Graph Transformation and Applications Abstract: Any computational method in chemistry must choose some level of precision in the modeling. One choice is made in the methods of quantum chemistry based on quantum field theory. While highly accurate, the methods are computationally very demanding, which restricts their practical use to single reactions of molecules of moderate size even when run on supercomputers. At the same time, most existing computational methods for systems chemistry and biology are formulated at the other abstraction extreme, in which the structure of molecules is represented either not at all or in a very rudimentary fashion that does not permit the tracking of individual atoms across a series of reactions. In this talk, we present our on-going work on creating a practical modelling framework for chemistry based on Double Pushout graph transformation, and how it can be applied to analyse chemical systems. We will address important technical design decisions as well as the importance of methods inspired from Algorithm Engineering in order to reach the required efficiency of our implementation. We will present chemically relevant features that our framework provides (e.g. automatic atom tracing) as well as a set of chemical systems we investigated are currently investigating. If time allows we will discuss variations of graph transformation rule compositions and their chemical validity. ___________________________________________________ [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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Shameless self-publicity
by ptj＠maths.cam.ac.uk 29 Nov '20

29 Nov '20

CAUTION: The Sender of this email is not from within Dalhousie. I imagine most people on this list will have heard that I had a serious bout with Covid-19 earlier this year, which put me in hospital for five months. I am deeply grateful to the many category-theorists who wrote to me at that time saying that I was in their thoughts. With that in mind, I thought people might be interested to read an article about my experience of the illness which has been written by the Publicity Officer of St John's College and published in the college magazine `Eagle Eye'. Here is the link: https://www.joh.cam.ac.uk/my-tears-are-tears-joy-because-i-cannot-believe-h… Peter Johnstone [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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quiver: a new commutative diagram editor
by Nathanael Arkor 27 Nov '20

27 Nov '20

CAUTION: The Sender of this email is not from within Dalhousie. Dear all, I would like to share a tool I have been developing for drawing commutative and pasting diagrams, which makes creating and modifying even large pasting diagrams essentially painless. Once drawn, the diagrams can be exported to LaTeX. The diagram editor is called quiver, and may be found here: https://q.uiver.app/ My desire is to make typesetting commutative diagrams as easy as drawing them by hand, and to cut down on the wasted time spent creating them in tikz-cd, xymatrix or TikZ. The editor is intended to be intuitive to use, but if you have any questions, please do send me an email. I would be glad to receive feedback (both general, and specific requests or issues), either by email or through the issue tracker. One closing request. There are some scenarios for which quiver does not yet emit LaTeX that perfectly matches the original diagram (e.g. diagrams involving 3-cells or higher), because I lack the necessary expertise to replicate these styles with TikZ. If anyone adept with TikZ would like to make quiver even better by working with me to improve the LaTeX output, I would love to hear from you. Thank you; I hope you find quiver useful! Nathanael Arkor [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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weakening(?) of locally connected
by Thomas Streicher 26 Nov '20

26 Nov '20

CAUTION: The Sender of this email is not from within Dalhousie. As is well known a geometric morphisms F --| U : EE -> SS is locally connected iff F preserves dependent products. But has anyone come across a g.m. whose inverse image part preserves ordinary function spaces, i.e. exponentials, but not dependent function spaces? In connection with Lawvere and Menni's TAC 30 paper (section 10) this question has been asked under the additional assumption that the g.m. is also hyperconnected and local. Triggered by discussion with Matias Menni I have thought about it with moderate success and then found out that I even do not know the answer to the (possibly) simpler question formulated at the beginning of this message. My hope now is that someone happens to know a counterexample to this simpler question at least... In my eyes the requirement that the further left adjoint be fibered/indexed is most natural if one thinks of gm's as cocomplete and locally small toposes over an arbitrary base topos (which I do as is apparent from my notes on Fibered Categories (section 18)). All examples of precohesive gm's I know of are locally connected. But it would be very surprising if this were always the case (unless the base is Set where essential and locally connected are known to coincide). Thanks in advance, Thomas [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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Kelly et al: “2-dimensional universal algebra” - references?
by Steve Vickers 25 Nov '20

25 Nov '20

CAUTION: The Sender of this email is not from within Dalhousie. The 1989 paper “Two-dimensional monad theory” (Blackwell, Kelly, Power) describes itself as “the first of a series of articles reporting the work of Kelly and various of his colleagues on what we may call two-dimensional universal algebra”. It refers to later articles on “two-dimensional structures defined by finite limit theories” and “presentations of monads and related syntactic issues”, to include “coherence results, to the effect that something non-strict may be replaced by an equivalent something that is non-strict”. Does anyone have references to these later papers, assuming they ever got written? I’ve looked through citations of the 1989 paper and didn’t spot anything obvious. Steve. [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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Around Toposes
by Olivia Caramello 23 Nov '20

23 Nov '20

CAUTION: The Sender of this email is not from within Dalhousie. Dear Category Theorists, I am glad to announce the creation of a new blog and forum about toposes: http://www.aroundtoposes.com This provides a platform for discussing about any aspect of toposes, at different levels of knowledge and technical sophistication, as well as a space where people interested in learning the subject can meet and set up reading groups. Anyone with these interests is welcome to join our forum. We look forward to seeing many of you there! Olivia [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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Reminder: Erik Palmgren memorial conference, Thu–Sat this week
by Peter LeFanu Lumsdaine 17 Nov '20

17 Nov '20

CAUTION: The Sender of this email is not from within Dalhousie. Dear all, As previously announced, the memorial conference for Erik Palmgren will be held online, this Thursday–Saturday, 9:00–11:30 and 13:30–16:30 Stockholm time. Full programme and other details are available at http://logic.math.su.se/palmgren-memorial/ . To receive the Zoom links, please register by emailing < palmgren-memorial(a)math.su.se> with your details, preferably by tomorrow morning. (We aren’t posting the Zoom details publicly, in order to prevent Zoom-bombing etc.) Best wishes, –Peter (for the organising committee) palmgren-memorial(a)math.su.se http://logic.math.su.se/palmgren-memorial/ [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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Next ItaCa Fest in November
by Giuseppe Metere 17 Nov '20

17 Nov '20

CAUTION: The Sender of this email is not from within Dalhousie. Dear colleagues and friends, I am writing to announce that the next ItaCaFest Seminar will be on Zoom Wednesday, 25 November 2020 and it will have the following schedule: 14:00 - Davide Trotta (Universita' di Verona) "The existential completion, choice principles and applications" 15:00 - Denis Nardin (Universit??t Regensburg) "Equivariant multiplicative structures" More details can be found on the conference webpage: progetto-itaca.github.io/pages/fest.html Attendance is free, no registration required, just follow the conference link at https://us02web.zoom.us/j/83503300759?pwd=NTNSRzRadEo1a3Uyc3ZSM3FVOGd5Zz09 Best regards, Beppe Metere (on behalf of the Programme Committee) -- Giuseppe Metere, PhD. Professore Associato di Algebra Dipartimento di Matematica e Informatica Universit?? degli Studi di Palermo [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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CSL 2021 - Call for Participation
by Alex Simpson 17 Nov '20

17 Nov '20

CAUTION: The Sender of this email is not from within Dalhousie. Readers of the categories mailing list may be interested in the online CSL conference, which takes place from Jan 25-28 2021 --- The European Association for Computer Science Logic invites you to participate in the 2021 edition of CSL, which will be held online from Mon Jan 25 to Thu Jan 28, 2021, organised by the Faculty of Mathematics and Physics at the University of Ljubljana # The Conference Computer Science Logic (CSL) is the annual conference of the European Association for Computer Science Logic (EACSL). It is an interdisciplinary conference spanning both basic and application-oriented research in mathematical logic and computer science. CSL 2021 will be the 29th edition in the series. CSL moved away from its former August/September slot in 2020. CSL 2021 is the second conference in the series that takes place in January. ## Invited Speakers - Assia Mahboubi, INRIA, Rennes, France - Sophia Drossopoulou, Imperial College, London, UK - Linda Westrick, Penn State University, State College, PA, USA - Sylvain Schmitz, Universit?? de Paris, Paris, France - Bartek Klin, Uniwersytet Warszawski, Warsawa, Poland ## Programme Thirty-four contributed papers have been selected for presentation at CSL 2021; see the [list of accepted papers](https://csl2021.fmf.uni-lj.si/accepted-papers/) ## Registration To register, please follow the link and information provided on the [CSL website](https://csl2021.fmf.uni-lj.si) The registration deadlines are: - *14th December 2020*: deadline for speaker registration. At least one author of every contributed paper must register as a speaker. - *11th January 2021*: deadline for non-speaker registration. All participants must register. Note that student non-speaker registration is free of charge. If you have any questions, please contact the local organisers <csl2021(a)fmf.uni-lj.si>. [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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