May 2018 - Categories - categories.org.au

Vera Trnkova
by Jirí Adámek 04 Jun '18

04 Jun '18

It is with great sadness that I inform you that last Sunday Vera Trnkova has passed away at the age of 84 years. In the last couple of years she suffered from a disease that made her life very difficult, so that she could only leave her appartment in a wheelchair. This is a great loss to the category theory community: Vera was an incredibly enthusiastic and gifted researcher, and her seminars, in which she made it possible for students from their early years to participate at topical research, were a great inspiration to the participants. She published a monograph, coauthored by Ales Pultr, on embeddings of categories, which was one of her life-long topics. And another one, coauthored by me, on the categorical theory of automata. In a series of more than 160 research articles she combined category theory with general topology, theoretical computer science and combinatorics. Another life-long topic of Vera's was the theory of set functors which she and her pupils developed in a substantial series of papers. That theory found applications in diverse areas of mathematics. Vera was also a dear friend, whose personality influenced a number of her colleagues and students. She will be missed by many of us. Jiri Adamek [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

2 1

Point-free affine real line?
by Steve Vickers 01 Jun '18

01 Jun '18

Algebraic geometry defines the affine line over a field k as an affine scheme, the spectrum of k[X]. It includes a copy of k, each element a being present as the irreducible polynomial X-a, with local ring the ring of fractions got by inverting polynomials f(X) such that f(a) is non-zero. You can carry this out for the real line R, but it is very much R as a set, and the copy of R in the underlying space of the spectrum has the discrete topology. Does algebraic geometry provide an analogous construction that could lead to the point-free R? Can the locally ringed space be topologized (point-free) so that the copy of R has its usual topology? I've run into various problems. 1. It is not obvious to me that R[X] exists point-free. By that I mean that, without presupposing a set R[X], or using non-geometric constructions, I can't see how to define a geometric theory whose models are the polynomials. The problem comes with trying to pin down the requirement that all but finitely many of the coefficients of a polynomial must be zero. You cannot continuously define the degree of a polynomial, because the function R -> N, a |-> degree(aX + 1), is not continuous. That suggests the construction as Spec(R[X]) might have to be adjusted. Is there still some locally ringed space that does the trick? 2. The "structure sheaf" cannot be a sheaf. We hope its fibres are point-free local rings, but, whatever they are, they must be R-algebras and so cannot have the discrete topology. The space is locally ringed by some bundle other than a sheaf (local homeomorphism). 3. The usual local rings, got as rings of fractions as described above, may be problematic point-free in the same way as R[X] is. I don't know what would do instead. The power series ring R[[X]]? (At least as fibre over 0.) It does have the property of inverting those polynomials f for which f(0) is non-zero. And it can be defined point-free, as R^N. (However, the finitely presented approximations R[X|X^n = 0] happily exist point-free.) Thanks for any references you can provide, Steve. [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

4 3

YaMCATS 15 University of Leicester 11 June 2018
by Paoli, Simona (Dr.) 30 May '18

30 May '18

Dear Colleagues, Just to rectify a typo in the heading my previous e-mail: the next YaMCATS meeting at the University of Leicester is Monday 11 June 2018. Apologies for the confusion. Best wishes, Simona (on behalf of the YaMCATS organizers). [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

1 0

20 years of deep inference, call for participation
by Lutz Strassburger 29 May '18

29 May '18

******************** Call for Participation ************************* TWENTY YEARS OF DEEP INFERENCE Oxford, July 7, 2018 Part of FLoC 2018 <https://www.lix.polytechnique.fr/~lutz/orgs/TYDI2018.html> ********************************************************************* Aim and Scope: -------------- Deep inference is a paradigm for designing deductive proof systems. The inference rules in such systems can perform arbitrary rewriting inside formulas. This is very different from what one would expect from more traditional formalisms, like sequent calculus or natural deduction, where formulas are always decomposed along their main connective. The purpose of this workshop is to - bring together researchers in the area of deep inference to exchange ideas and to discuss their current work, and - present this vast growing field in a coherent, easy accessible way to other communities in all areas of logic in computer science. In particular, there will be a gentle introduction to deep inference given by Willem Heijltjes (University of Bath). Invited Talks: -------------- Willem Heijltjes (University of Bath): "An introduction to deep inference" Alessio Guglielmi(University of Bath): "Two Unifying Structural Principles" Dominic Hughes (UC Berkeley): "Some incoherent musings on deep inference and combinatorial proofs" Anupam Das (University of Copenhagen): "Proof complexity of deep inference: a survey" Contributed Talks: ------------------ Joseph Paulus: "Deep-Inference Intersection Types" Ross Horne: "Truely Concurrent Processes in the Calculus of Structures" Elaine Pimentel: "Sequentialising nested systems" Sonia Marin: "Nested sequents for modal logics and beyond" Benjamin Ralph: "Deep Inference, Herbrand???s Theorem and Expansion Proofs" Registration: ------------- Please use the FLoC registration page: <http://www.floc2018.org/register/> Note: Early registration ends on June 6! Accomodation: ------------- can be booked via the FLoC accomodation page: <http://www.floc2018.org/accommodation/> Organization: ------------- Andrea Aler-Tubella (IRIF, CNRS & Univ. Diderot) Lutz Stra??burger (Inria Saclay) [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

1 0

CGASA dedicates a volume to Prof Gratzer
by Mojgan Mahmoudi 28 May '18

28 May '18

Dear Colleagues As we mentioned before, this is to announce that: In honor of Professor George A. Gratzer, we are going to celebrate (i) 55th anniversary of the publication of Gratzer–Schmidt Theorem, and (ii) 40the anniversary of Gratzer’s General Lattice Theory book, and many other his contributions to Universal Algebra and Lattice Theory, by dedicating a volume of our journal CGASA (Categories and General Algebraic Structures with Applications: www.cgasa.ir) to him. We invite all of you to join this events by submitting your papers. The deadline to submit papers is September 30, 2018. Best Regards, Mojgan Mahmoudi and M. Mehdi Ebrahimi On behalf of the Editorial Board ************************* Mojgan Mahmoudi; Professor Department of Mathematics, Shahid Beheshti University, Tehran 19839, IRAN. Telefax: (+98)(21)(22431652) E-mail: m-mahmoudi(a)sbu.ac.ir, mojganmahmoudi(a)yahoo.com http://faculties.sbu.ac.ir/m-mahmoudi/ [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

1 0

YaMCATS 15 University of Leicester 18 June 2018
by Paoli, Simona (Dr.) 27 May '18

27 May '18

Dear Colleagues, the next meeting of the Yorkshire and Midlands Category Seminar will take place at the University of Leicester on Monday 11 June 2018. The invited speakers are: Alexander Kurz (University of Leicester) Sandra Mantovani (University of Milano) Sean Moss (University of Oxford) Andy Tonks (University of Leicester) Further details can be found on the YaMCATS website. Best wishes, The YaMCATS organizers Simona Paoli, Nicola Gambino, Steve Vickers, Scott Balchin. [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

1 0

copowers/weighted colimits in (V-Cat)-Cat
by David Roberts 18 May '18

18 May '18

Hi all, I'm looking for a reference that discusses the existence of weighted colimits in (V-Cat)-Cat, where V is a symmetric monoidal category that is suitably complete and cocomplete. I have in mind V=Vect or otherwise some flavour of topological vector spaces. In particular I'd be interested discussion/description of copowers of V-Cat-categories by finite V-categories. Thanks David David Roberts http://ncatlab.org/nlab/show/David+Roberts [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

1 0

postdoc at Macquarie
by Steve Lack 16 May '18

16 May '18

The Centre of Australian Category Theory is advertising for a postdoc. The position is for 2 years and the ad is here http://jobs.mq.edu.au/cw/en/job/503874/postdoctoral-research-fellow Feel free to ask me or any of the other Macquarie people if you have questions. Regards, Steve Lack. [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

1 0

"Toposes in Como" - second announcement
by Olivia Caramello 16 May '18

16 May '18

Dear All, This is the second announcement of the following international event (school + conference) on topos theory, which will take place in Como from 24 to 29 June 2018. We hope to see you in Como. Best regards, Olivia Caramello (on behalf of the Scientific and Organizing Committees) ============================================================================ === TOPOSES IN COMO Call for participation School: 24-26 June 2018 - Conference: 27-29 June 2018 Lake Como School of Advanced Studies and Università degli Studi dell'Insubria http://tcsc.lakecomoschool.org * Scope * ------------ The event "Toposes in Como", which represents the second edition of the conference "Topos à l'IHES" held in France in 2015, will consist of a three-day school, offering introductory courses for the benefit of students and mathematicians who are not already familiar with topos theory, followed by a three-day conference featuring both invited and contributed presentations on new theoretical advances in the subject as well as applications of toposes in different fields such as algebra, topology, number theory, algebraic geometry, logic, homotopy theory, functional analysis and computer science. * School lecturers * -------------------------- Francis BORCEUX (Université Catholique de Louvain) Olivia CARAMELLO (Università degli Studi dell'Insubria - Como) Alain CONNES (IHES) Laurent LAFFORGUE (IHES) * Conference invited speakers * ------------------------------------------ Tibor BEKE (University of Massachusetts) Ingo BLECHSCHMIDT (University of Augsburg) Eduardo DUBUC (University of Buenos Aires) Pieter HOFSTRA (University of Ottawa) Maria Emilia MAIETTI (Università degli Studi di Padova) Andrew PITTS (University of Cambridge) Mauro PORTA (Université de Strasbourg) Bas SPITTERS (Aarhus University) David SPIVAK (MIT) * Scientific Committee * -------------------------------- Olivia CARAMELLO Alain CONNES Caterina CONSANI Laurent LAFFORGUE * Organizing Committee * ---------------------------------- Olivia CARAMELLO Franco CAZZANIGA Stefano PIGOLA Lidia STOPPINO * Registration and contact * ------------------------------------ Registration information is available at the conference webpage http://tcsc.lakecomoschool.org/registration/ If you have any queries please send them to the conference e-mail address tcsc(a)lakecomoschool.org ============================================================================ === [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

1 0

CT 2018 - deadlines
by CT2018 16 May '18

16 May '18

Dear Colleagues, We would like to remind you of the following deadlines - abstract submission: *May 25, 2018* - early registration: *June 10, 2018* You may find further information concerning CT 2018 at http://www.mat.uc.pt/~ct2018/ With best regards, The Organising Committee -- Category Theory :: ct2018(a)mat.uc.pt [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

1 0