November 2010 - Categories - categories.org.au

Research positions
by Maria Manuel Clementino 26 Feb '14

26 Feb '14

5-YEAR RESEARCH POSITIONS The Centre for Mathematics of the University of Coimbra (CMUC) invites applications for five 5-year research positions in all areas of Mathematics. Applicants should have a PhD in Mathematics and at least three years of post-doctoral experience, with an international-level publication record and demonstrated ability to perform independent research. Preference will be given to candidates working in one of the areas in which the members of CMUC are currently active. A very good command of English is required. The appointments will be made for three years, renewable for two more. Successful applicants are expected to develop research within the areas of interest of CMUC. They should also contribute to graduate studies, supervising students from the Department of Mathematics. The basic salary is equivalent to the index 195 of the Portuguese research career (in the order of 42 500 euros a year), in accordance with the Ciência 2008 guidelines http://alfa.fct.mctes.pt/apoios/contratacaodoutorados/edital2008 Benefits include private health insurance and social security. Applicants should send • cover sheet (available from www.mat.uc.pt/cmuc/coversheet.pdf) including names and contact information of three persons who can provide a letter of recommendation • curriculum vitae (publication list included) • a 5-year research proposal (2 pages max), emphasizing their own research goals as pdf files to cmuc(a)mat.uc.pt. The subject of the e-mail message must include the job reference C2008 FCTUC CMUC v15-v19. The deadline for applications is *September 10, 2008.* ------------------------------ More information can be found at www.mat.uc.pt

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separable locale
by Thomas Streicher 17 May '13

17 May '13

Recently rereading Fourman's "Continuous Truth" I came across the term "separable locale" but could nowhere find an explanation. Does it mean a cHa A for which there exists a countable subset B such that ever a in A is the supremum of those b in B with b leq a. This would be the point free account of "second countable", i.e. having a countable basis. Of course, second countable T_) spaces are separable, i.e. have a countable dense set. Is this reading the "usual" one? Thomas [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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What else do simplicial sets classify?
by Andrej Bauer 04 Oct '11

04 Oct '11

The presheaf category of simplicial sets is the classifying topos for the theory L of a bounded linear order. In general, there could be other theories which are "Morita equivalent" to L in the sense that their classifying toposes are equivalent to simplicial sets. Are any such known, preferably occurring in nature? With kind regards, Andrej [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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Is "braided monoidal" a conservative extension of "lax braided monoidal"?
by Alan Jeffrey 30 Nov '10

30 Nov '10

Hi everyone, Is there a known result (or counterexample) saying that the equational theory of a braided monoidal category is a conservative extension of a lax braided monoidal category? As a reminder, a lax braid is a natural b : A * B -> B * A satisfying coherence conditions with the units and associators, and a braid is a lax braid where b is an isomorphism. The motivation for asking this question is that string diagrams are a proof technique for braids, and I'd like to be able to use them for lax braids too, but this requires braiding to be a conservative extension of lax braiding. Cheers, Alan Jeffrey. [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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16th Estonian Winter School in Computer Science, Call for Partic.
by Tarmo Uustalu 27 Nov '10

27 Nov '10

[Lecturers: Boyen, Goré, Hofmann, Jacobs, Sadeghi. Place/time: Palmse, Estonia, 27 Feb-4 March 2011. Deadline for application and submission of abstracts for student talks: ** 14 Jan 2011 **.] CALL for PARTICIPATION 16th Estonian Winter School in Computer Science, EWSCS '11 Palmse, Estonia, 27 Feb-4 March 2011 http://cs.ioc.ee/ewscs/2011/ BACKGROUND AND OBJECTIVES EWSCS is a series of regional-scope international winter schools held annually in Estonia. EWSCS are organized by Institute of Cybernetics, a research institute of Tallinn University of Technology. The main objective of EWSCS is to expose Estonian, Baltic, and Nordic graduate students in computer science (but also interested students from elsewhere) to frontline research topics usually not covered within the regular curricula. The working language of the schools is English. EWSCS '11 is the sixteenth event of the series. PROGRAMME The schools' scientific programme consists of short courses by renowned specialists and a student session. Courses of EWSCS '11 * Xavier Boyen (Université de Liège, Belgium): Lattice-based cryptology * Rajeev Goré (Australian National University, Canberra, Australia): Automated reasoning in modal, tense and temporal logics * Martin Hofmann (Ludwig-Maximilians-Universität München, Germany): Amortized resource analysis * Bart Jacobs (Radboud Universiteit Nijmegen, The Netherlands): Introduction to coalgebra * Ahmad-Reza Sadeghi (Technische Universität Darmstadt and Fraunhofer-Institut für Sichere Informationstechnologie, Germany): Trusted and trustworthy computing: are we ready for clouds? The purpose of the student session is to give students an opportunity to present their work (typically, thesis work) and get feedback. Registrants are invited to propose short talks (20 min) on topics of theoretical computer science, broadly understood. The selection will be based on abstracts of 150-400 words. The social programme consists of an excursion and a conference dinner. VENUE Palmse is a small settlement 80 kms to the east from Tallinn in the county of Lääne-Viru. It is renowned for a large manor that used to belong to the von Pahlen family, today hosting the visitors' center of the Lahemaa National Park, a museum, and a hotel. Tallinn, Estonia's capital, is famous for its picturesque medieval Old Town, a UNESCO World Heritage site. In 2011, Tallinn, along with Turku in Finland, is the cultural capital of Europe. There are direct flights to Tallinn Lennart Meri airport from Amsterdam, Brussels, Copenhagen, Dublin, Düsseldorf Weeze, Edinburgh, Frankfurt, Gothenburg, Helsinki, Kiev, London Gatwick, Luton and Stansted, Milan Bergamo and Malpensa, Moscow, Munich, Oslo Gardermoen and Rygge, Prague, Riga, Stockholm Arlanda and Skavsta, St Petersburg, Warsaw and Vilnius, ferries from Stockholm and Helsinki. From Vilnius, Riga, St Petersburg the Lux Express coach services are the practical travel option. APPLICATION AND COST The deadline for application and submission of student talk abstracts is 14 January 2011. All applicants will be notified of admission to the school and acceptance of their talks by 28 January 2011. Admitted applicants are entitled and expected to attend the courses and student session of the school. They will also receive a binder with the course material and access to additional materials on the school website. The participation fee is 320 EUR and includes full board accommodation at Palmse, transportation from Tallinn to Palmse, the excursion and conference dinner (by contributing towards the associated expense). We may be able to reduce the fee for a small number of participants. To apply for fee reduction, please fill in the online fee reduction request form. PROGRAMME COMMITTEE / ORGANISING COMMITTEE * Tarmo Uustalu (Institute of Cybernetics) (chair) * Monika Perkmann (Institute of Cybernetics) (secretary) * Helger Lipmaa (Cybernetica AS) * Peeter Laud (Cybernetica AS) * Varmo Vene (University of Tartu) * Sven Laur (University of Tartu) SPONSORS * Tiger University Plus programme of the Estonian Information Technology Foundation * Estonian Centre of Excellence in Computer Science, EXCS, funded by the European Regional Development Fund FURTHER INFORMATION Details on the application procedure and cost, submission of student talk abstrats are available from the school webpage, http://cs.ioc.ee/ewscs/2011/. Questions should be sent to ewscs11(at)cs.ioc.ee. [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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Re: Proving enough injectives for modules over a Grothendieck topos
by Colin McLarty 26 Nov '10

26 Nov '10

This proof really fell through the cracks. The argument from injective Abelian groups to injective R-modules was known by 1960. The last piece was in place in 1974 with Barr's theorem on coverings with AC. The proof may be published somewhere but I can't find it and Peter suggests it is not. Its absence works mischief. Eisenbud COMMUTATIVE ALGEBRA (p. 621) proves modules (n Set) have enough injectives and then sends readers off to Hartshorne for the Godement construction to prove modules over topological spaces have enough injectives. But he has in effect already proved it for all Grothendieck toposes! He merely has to send readers off to Mike's paper or Peter's (1977) book for the AC result. While Eisenbud states results explicitly for module categories over Sets, he frames them to hold much more generally and he sends readers to sources for that generality. I am glad to hear it will be in the Elephant. best, Colin PS thanks to Carsten Butz for reminding me of Andreas Blass "Injectivity, projectivity, and the axiom of choice" (Trans. AMS Volume 255, November 1979) for both history and a proof that choice will be required. 2010/10/11 Prof. Peter Johnstone <P.T.Johnstone(a)dpmms.cam.ac.uk>: > Dear Colin, > > Yes, the argument is correct, and it'll be in volume 3 of the Elephant. > I don't know why it hasn't been published elsewhere. > > Peter > [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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free access to logica universalis / papers of interes]
by Universal Logic 24 Nov '10

24 Nov '10

Free access to all papers published in Logica Universalis is avalaible up to November 30: http://www.springer.com/birkhauser/mathematics/journal/11787 Last issue of the journal is on the topic "is logic universal?" In the next future there will be special issues of the journal on the following topics: - Visual reasoning with diagrams - Multimodal logics - Categorical logics - Hexagon of opposition Subscription to the print version (hard copy) of the journal is avalaible at a very good price for individuals (38 euros per year including postage and handling). Among many interesting papers published since the start of the journal - freely downloadable up to November 30 - you can find: A New Modal Lindstroom Theorem Johan van Benthem http://www.springerlink.com/content/t26u1781q78508x2/ Generalized Definitional Reflection and the Inversion Principle Peter Schroeder-Heister http://www.springerlink.com/content/e543v66615054247/ Structuralist Logic: Implications, Inferences, and Consequences Arnold Koslow http://www.springerlink.com/content/b7115xg144h521g1/ Things That are Right with the Traditional Square of Opposition Terence Parsons http://www.springerlink.com/content/813595g60860521g/ Applications of Squares of Oppositions and Their Generalizations in Philosophical Analysis Jan Wolenski http://www.springerlink.com/content/g7063211k0543g72/ Russell and His Sources for Non-Classical Logics Irving H. Anellis http://www.springerlink.com/content/u1u6432708318164/ The Concept of Relevance and the Logic Diagram Tradition Jan Dejnozka http://www.springerlink.com/content/502120568051v101/ What is a Logic Translation? Till Mossakowski, Razvan Diaconescu and Andrzej Tarlecki http://www.springerlink.com/content/k768u15734x5l230/ Symmetric Generalized Galois Logics Katalin Bimbó and J. Michael Dunn http://www.springerlink.com/content/4t680856130n006l/ >------------------ Jean-Yves Beziau Editor-in-Chief Logica Universalis http://www.logica-universalis.org [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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Bilimit question
by Alex Hoffnung 23 Nov '10

23 Nov '10

Dear List, The weakest form of limits in a bicategory are defined by equivalences of hom-categories in place of the slightly more strict version defined by isomorphisms. Then the process of defining a monoidal structure on a bicategory with finite products takes on a slightly different flavor in each case. In the weak case, given a pair of 1-cells one must *choose* a monoidal product, whereas in the latter case, a *unique choice* of monoidal product can be obtained from the one-dimensional aspect of the universal property. I would guess that in the former case, one should not worry too much about how to choose the product 1-cells, since the universal property will come to the rescue when checking that one has indeed defined a monoidal structure on the bicategory. Does anyone know of a reference which proves something along these lines? Best, Alex [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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Leo Esakia
by Mamuka Jibladze 22 Nov '10

22 Nov '10

Dear Colleagues, It is with great sadness that we announce the passing of Leo Esakia on November 17, 2010. This is a big loss for all of Leo's friends, colleagues, and students, but also for the logic community as a whole. Leo was the founder and the anchor of the logic school in Georgia. He was a constant source of wisdom, inspiration, and encouragement to all of his colleagues and students. Leo made numerous important contributions to the study of algebraic and topological semantics of intuitionistic and modal logics. Several landmark theorems in the field bear his name. He also contributed immensely to establishing a strong research community working on algebraic, topological, and categorical methods in logic. Leo Esakia was not only a brilliant mathematician, but also an extraordinary human being. He will stay in our memory as a wonderful, charming, refined, and attentive person who was always there to give his support, encouragement, and guidance. He will be sorely missed. We believe his scientific legacy will be long remembered, and his ideas will carry forward. Our thoughts are with Leo's family at these difficult times. Guram Bezhanishvili Nick Bezhanishvili David Gabelaia Mamuka Jibladze Dimitri Pataraia [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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Union College Conference
by Niefield, Susan 19 Nov '10

19 Nov '10

UNION COLLEGE MATHEMATICS CONFERENCE Saturday and Sunday Schenectady April 30 - May 1, 2011 New York This is a preliminary announcement for the thirteenth Union College Mathematics Conference. This year the conference topics are algebraic topology, applied mathematics and category theory. In addition to plenary lectures of interest to the entire Conference audience, there will also be shorter contributed talks in parallel sessions. Anyone interested in giving such a talk should contact one of the organizers. The meeting will begin with an evening reception on Friday, April 29, and end on Sunday afternoon. More information will be available at the Union College Mathematics Department website (www.math.union.edu) in January. Union College is centrally located in New York's capital district about 10 miles from the Albany International Airport, easily accessible by train from NYC, and just 3 to 4 hours by car from NYC, Boston, and Montreal. We hope to see you here in the spring! ORGANIZERS Category Theory Susan Niefield (niefiels(a)union.edu) Algebraic Topology Brenda Johnson (johnsonb(a)union.edu) Kathryn Lesh (leshk(a)union.edu) Applied Mathematics Hubert Noussi (noussih(a)union.edu) Jue Wang (wangj(a)union.edu) [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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