April 2011 - 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 05 Oct '11

05 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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Re: Explanations
by peasthope＠shaw.ca 03 May '11

03 May '11

Charles & everyone, Earlier peasthope wrote, "...changing a few words of a sentence can make a concept obvious rather than nebulous". Revise that to "obvious rather than difficult". From: Charles Wells <charles(a)abstractmath.org> Date: Fri, 22 Apr 2011 09:37:44 -0500 > Can you give specific examples? I suspect that in most cases the change > introduces a useful metaphor that was hidden before. Here is a small example from the _Conceptual Mathematics_ of Lawvere and Schanuel. No offense to the authors or the book. It's an indispensible and invaluable resource. L&S page 292, "Definition ... equalizer ... and for each x:T-->X ... there is exactly one e:T-->E ... ." "For all T" is implicit. http://en.wikipedia.org/wiki/Equalizer_(Mathematics) , "In category theory ... defined by a universal property, ... object E and morphism eq ... such that, given any other object O and morphism m ... ." For me, the reference to "any other object O" helps. The definition in the Wikipedia seems to reveal the "universality" of the equalizer better. The diagram also helps. A trivial issue for most readers but a small detail can make a difference for a student. Regards, ... Peter E. -- Telephone 1 360 450 2132. bcc: peasthope at shaw.ca Shop pages http://carnot.yi.org/ accessible as long as the old drives survive. Personal pages http://members.shaw.ca/peasthope/ . [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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CT2011 Abstracts
by Steve Lack 30 Apr '11

30 Apr '11

Dear Colleagues, The original deadline for abstract submission for the International Category Theory Conference (CT2011) was May 1. This has now been extended until June 1. I would ask, however, those who have not already submitted an abstract and intend to do so, to send me a message by May 1 notifying me of their intention to submit. The conference website is http://www.mat.uc.pt/~ct2011/ . Steve Lack (Chair of Scientific Committee) [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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Final call for contributions: CALCO-Jnr 2011: CALCO Young Researchers Workshop (Winchester, UK)
by Toby Wilkinson 29 Apr '11

29 Apr '11

!!! Please forward to PhD students and young researchers !!! =============================================================== FINAL CALL FOR CONTRIBUTIONS: CALCO-Jnr 2011 CALCO Young Researchers Workshop August 29, 2011, Winchester, UK part of 4th Conference on Algebra and Coalgebra in Computer Science August 29-September 2, 2011, Winchester, UK =============================================================== Abstract submission: May 8, 2011 Author notification: May 30, 2011 Final abstract due: June 30, 2011 Full paper submission: September 30, 2011 =============================================================== http://calco2011.ecs.soton.ac.uk/ =============================================================== CALCO 2011 will be preceded by the CALCO Young Researchers Workshop, CALCO-Jnr, dedicated to presentations by PhD students and by those who completed their doctoral studies within the past few years. CALCO aims to bring together researchers and practitioners with interests in foundational aspects, and both traditional and emerging uses of algebras and coalgebras in computer science. The study of algebra and coalgebra relates to the data, process and structural aspects of software systems. This is a high-level, bi-annual conference formed by joining the forces and reputations of CMCS (the International Workshop on Coalgebraic Methods in Computer Science), and WADT (the Workshop on Algebraic Development Techniques). Previous CALCO editions took place in Swansea (Wales, 2005), Bergen (Norway, 2007) and Udine (Italy, 2009). The fourth edition will be held in the city of Winchester (England), a historic cathedral city and the ancient capital of Wessex and the Kingdom of England. The CALCO Young Researchers Workshop, CALCO-Jnr, is a CALCO satellite workshop dedicated to presentations by PhD students and young researchers. Attendance at the workshop is open to all - it is anticipated that many CALCO conference participants will want to attend the CALCO-Jnr workshop (and vice versa). Topics of Interest ----------------------- The CALCO Young Researchers Workshop invites submissions on the same topics as the CALCO conference: reporting results of theoretical work on the mathematics of algebras and coalgebras, the way these results can support methods and techniques for software development, as well as experience with the transfer of the resulting technologies into industrial practice. In particular, the workshop encourages submissions related to the topics listed below. * Abstract models and logics - Automata and languages, - Categorical semantics, - Modal logics, - Relational systems, - Graph transformation, - Term rewriting, - Adhesive categories * Specialised models and calculi - Hybrid, probabilistic, and timed systems, - Calculi and models of concurrent, distributed, mobile, and context-aware computing, - General systems theory and computational models (chemical, biological, etc) * Algebraic and coalgebraic semantics - Abstract data types, - Inductive and coinductive methods, - Re-engineering techniques (program transformation), - Semantics of conceptual modelling methods and techniques, - Semantics of programming languages * System specification and verification - Algebraic and coalgebraic specification, - Formal testing and quality assurance, - Validation and verification, - Generative programming and model-driven development, - Models, correctness and (re)configuration of hardware/middleware/architectures, - Process algebra Submission ---------------- CALCO-Jnr presentations will be selected according to originality, significance, and general interest, on the basis of submitted 2-page abstracts. A booklet with the abstracts of the accepted presentations will be available at the workshop. Submissions are handled via the following link: https://www.easychair.org/conferences/?conf=calcojnr2011. The use of LNCS style (see http://www.springer.de/compo/lncs/authors.html) is strongly encouraged. After the workshop, the author(s) of each presentation will be invited to submit a full 10-15 page paper on the same topic. They will also be asked to write (anonymous) reviews of papers submitted by other authors on related topics. Additional reviewing and the final selection of papers will be carried out by the CALCO-Jnr PC. The volume of selected papers from the workshop will be published as a technical report of the University of Southampton. Authors will retain copyright, and are also encouraged to disseminate the results reported at CALCO-Jnr by subsequent publication elsewhere. Important Dates ---------------------- May 8, 2011 Deadline for 2-page abstract submission May 30, 2011 Notification of abstract selection decision June 30, 2011 Final version of abstract due August 29, 2011 CALCO-Jnr, CALCO Young Researchers Workshop August 30 -September 2, 2011 CALCO technical programme September 30, 2011 Deadline for 10-15 page paper submission November 15, 2011 Notification of paper selection decision November 30, 2011 Final version of paper due Programme Committee -------------------------------- * Corina Cirstea, University of Southampton, UK http://www.ecs.soton.ac.uk/people/cc2 * Magne Haveraaen, University of Bergen, NO http://www.ii.uib.no/~magne/ * John Power, University of Bath, UK http://www.bath.ac.uk/comp-sci/people/contact/index.php?contact=Dr_John_Pow… * Monika Seisenberger (chair), Swansea University, UK http://www.cs.swan.ac.uk/~csmona/ * Toby Wilkinson, University of Southampton, UK http://www.ecs.soton.ac.uk/people/stw08r Posters ------------ * Low quality (for online viewing) http://calco2011.ecs.soton.ac.uk/workshops/calcojnr.jpg * High quality (for printing) http://calco2011.ecs.soton.ac.uk/workshops/calcojnr.pdf --- CALCO-Jnr 2011: http://calco2011.ecs.soton.ac.uk/workshops/calco-jnr.html CALCO 2011: http://calco2011.ecs.soton.ac.uk/ [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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Re: Explanations
by Marta Bunge 28 Apr '11

28 Apr '11

Dear Andre, In connection with the current discussion on explanatory proofs, and more particularly about the difference between computer generated proofs and human ones, I have something to add to what you wrote --drawn from my own experience. Humans do not have either the speed or the ability to hold the enormous amounts of information that machines do. On the other hand, the only way to see the big picture is speed of reasoning coupled with intuition - naturally without checking the details at each step. That way, two things may happen to humans of which computers are free of: (1) errors are made, and (2) new ideas originate. Errors are not a good thing, of course, but they are a possible outcome from taking risks, without which no new ideas would ever surface. Working out the details of that first glimpse of the truth may be painful, but necessary. It may lead to truth (hardly ever), or to further glimpses. I agree with you that the sequence intuition --> computation---> intuition---> computation-->.... is the only available course of action for a good mathematician. With luck, the sequence terminates eventually, and it does in truth. But it must begin with intuition. Some of my collaborators have expressed surprise at my starting any investigation with a title and an abstract, when they would leave both for the end. Naturally, that title and abstract may very well change at the end of the investigation, but if I were incapable to see the big picture at first, I would not begin any work at all. A final trivial thought - computation alone is not mathematics, and neither is intuition alone. The former is typical of machines, whereas the latter is typical of artists. Best regards,Marta ---------------------------------------- > Date: Mon, 25 Apr 2011 22:01:05 -0400 > Subject: categories: Re: Explanations > From: joyal.andre(a)uqam.ca > To: jds(a)math.upenn.edu; ronnie.profbrown(a)btinternet.com; graham(a)eecs.qmul.ac.uk > > Dear Jim, > > You are perfectly right! > I am always amazed by the fact that a computation > can yield a surprising result. > It is as if the formal system knew more than me! > Actually, I find a computation boring when the result is not surprising. > Computing is probably the main vehicule by which we can move > beyond a given body of intuitive knowledges. > But after the initial surprise, we try hard to > integrate the new result in a larger body, > where it may become less surprising. > It may even become obvious! > > The chain > > intuition--->computation---->intuition--->computation..... > > is probably more important than the chain > > proof--->method---->proof--->method..... > > André > [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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Re: Topology at the VU
by Timothy Porter 28 Apr '11

28 Apr '11

Dear All, This is something that the categorical community may feel strongly about. I was circulated by the Alg Top List having initially been sent to various other lists by people at Amsterdam. Tim -------------------------------- Dear ... My university has put forward a plan to close the Geometry Section of the department of mathematics. This means that 4 mathematicians - Jan Dijkstra, Rob de Jeu, Dietrich Notbohm and Tilman Bauer - will lose their jobs. For me personally there is no problem since I will take early retirement by January 1, 2012. This I decided already more than one year ago since I want to spend my remaining good years on mathematics and nothing but mathematics and traveling around the globe. But for my colleagues, this is a terrible disaster and it is also a disaster for topology. You can help them by signing the petition below by clicking on the link and follow the necessary steps. Please forward this message to mathematicians in your community. We need your help now. Only if many mathematicians will protest, this may have an effect. Best wishes, Jan van Mill http://www.gopetition.com/petitions/save-pure-mathematics-at-the-vu-univers… As with most universities in the Netherlands, the VU University Amsterdam suffers from financial underfunding. All faculties and all departments at the VU are asked to take measures to deal with this problem. For the Department of Mathematics a committee of applied mathematicians has put forward a proposal to close the Geometry Section, which consists of six tenured positions and focuses on algebraic K-theory, algebraic topology, and general/geometric topology. At the same time, some of the funds freed up by the abolition of the Geometry Section are to be used for the creation of two additional positions in the Analysis Section. This proposal has received the endorsement of the Dean of the Faculty of Sciences and of the Executive Board of the university. Two members of the Geometry Section will retire in the next two years and closure of the section will allow for termination of the other four tenured positions. Thus, the proposal's drastic measures will merely cut the total number of positions by two. Of the four positions slated for termination, one is in general/geometric topology and has been held since 2001 by Jan Dijkstra. The other three people were appointed less than four years ago: Dietrich Notbohm, Rob de Jeu, and Tilman Bauer. This introduced algebraic K-theory and algebraic topology as new research subjects at the VU. In 2010, a research evaluation of all Dutch mathematics departments by an international committee took place. The committee welcomed these changes very much, stating that strong young people provided new impetus to the group in mainstream mathematics and offered promise for the future. What are the consequences of the closure of the Geometry Section for the university? Algebra, algebraic topology, and general/geometric topology will vanish. Algebraic K-theory and general/geometric topology will cease to exist in the Netherlands, and only Utrecht will be left with research in algebraic topology. No pure mathematicians will be on the staff anymore. The university will give up central areas of mathematics and adopt a narrow research profile. The education of students offered at the VU will also become much narrower, which may lead to a drop in the yearly intake of students, and will certainly compromise the academic chances for VU graduates. This petition asks for a reconsideration of this plan. By signing it you will help to save the Geometry Section at the Department of Mathematics at the VU! Petition: I appeal to the Department of Mathematics, the Faculty of Sciences, and the Executive Board of the VU University Amsterdam to repeal the plan to close the Geometry Section. Proceeding with the proposal as it stands would severely damage the quality of research and teaching in mathematics at the VU. Laying off capable tenured faculty and hiring new faculty at the same time is intolerable. ** [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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MFPS 27 - Second Call for Participation
by Michael Mislove 28 Apr '11

28 Apr '11

Dear Colleagues, This is the second Call for Participation at MFPS XXVII, the Twenty-seventh Conference on the Mathematical Foundations of Programming Semantics, which will take place on the campus of the Carnegie Mellon University, Pittsburgh, PA, USA, from May 25 to May 28, 2011. The meeting will include plenary lectures by Steve Brookes (CMU), Jérôme Feret (INRIA), John Reynolds (CMU), Alex Simpson (Edinburgh), Stephanie Weirich (Penn) and Steve Zdancewic (Penn). The program also includes a special session honoring John Reynolds on his 75th birthday, a session on systems biology, and a session on security, as well as tutorial lectures on "Programs from Proofs", and fourteen contributed talks selected by the PC for presentation at the meeting. Complete details about the program can be found at the web site http://www.math.tulane.edu/~mfps/MFPS27 Registration is now open, and registration information for the meeting also is available on the web site. Please note that the conference hotel will not guarantee to honor the conference rate after next Monday, May 2, so please make you hotel arrangements by then to obtain the conference rate. Any questions can be directed to mfps(a)math.tulane.edu Best regards, Mike Mislove Joel Ouaknine, Chair, Program Committee [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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Explanations
by Jean-Pierre Marquis 27 Apr '11

27 Apr '11

Hi, I have a general question which is not strictly speaking about categories, but I thought I would ask the members of the list anyhow. Here is the context: some people claim that there are mathematical proofs that are explanatory, that is, not only do they establish the claim they prove, but they also show why the given result holds. Here is my question: is there any proof, involving categories or not (but preferably so), that you would consider as being explanatory in this sense? Please answer off-list. Thanks, Jean-Pierre Jean-Pierre Marquis Professeur titulaire Responsable du premier cycle Département de philosophie Université de Montréal jean-pierre.marquis(a)umontreal.ca Tel: 514-343-6111 (33445) Télécopieur: 514-343-7899 [For admin and other information see: http://www.mta.ca/~cat-dist/ ]

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