March 2008 - Categories - categories.org.au

Foundations?
by F W Lawvere 03 Sep '10

03 Sep '10

Down with "Foundations"! Up with algebra! Dear Friends, Presumably I am among those who are being "vilified" as "lovers of categories as foundation". By avoiding any precise definition, such a formulation might appeal to the widespread justified boredom induced by the past hundred years of "foundations as justification". Whenever I used the word "foundation" in my writings over the past forty years, I have explicitly rejected that reactionary use of the term and instead used the definition implicit in the work of my teachers Truesdell and Eilenberg. Namely, an important component of mathematical practice is the careful study of historical and contemporary analysis, geometry, etc. to extract the essential recurring concepts and constructions; making those concepts and constructions (such as homomorphism, functional, adjoint functor, etc.) explicit provides powerful guidance for further unified development of all mathematical subjects, old and new. What is the primary tool for such summing up of the essence of ongoing mathematics? Algebra! Nodal points in the progress of this kind of research occur when, as is the case with the finite number of axioms for the metacategory of categories, all that we know so far can be expressed in a single sort of algebra. I am proud to have participated with Eilenberg, Mac Lane, Freyd, and many others, in bringing about the contemporary awareness of Algebra as Category Theory Had it not been for the century of excessive attention given to the alleged possibility that mathematics is inconsistent, with the accompanying degradation of the F-word, we would still be using it in the sense known to the general public: the search for what is "basic". We, who supposedly know the explicit algebra of homomorphisms, functionals, etc. are long remiss in our duty to find ways to utilize those concepts also in guiding high school calculus. Best wishes, Bill Bibliography: - The Category of Categories as a Foundation for Mathematics, La Jolla conference 1965, Springer (1966) - Adjointness in Foundations, Dialectica, (1969), to be reprinted in TAC - Foundations and Applications: Axiomatization and Education, Bulletin of Symbolic Logic, (2003) vol 9, pp 213-224 - Sets for Mathematics, w/ Bob Rosebrugh, Cambridge Univ. Press, (2003) ************************************************************ F. William Lawvere Mathematics Department, State University of New York 244 Mathematics Building, Buffalo, N.Y. 14260-2900 USA Tel. 716-645-6284 HOMEPAGE: http://www.acsu.buffalo.edu/~wlawvere ************************************************************

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exploiting similarities and analogies
by Al Vilcius 03 Apr '08

03 Apr '08

Dear Categorists, Has anyone explored, either formally or informally, the connection between the Melzak Bypass Principle (MBP) and adjoints? The MBP (aka "the conjugacy principle" which embraces and generalizes Jacobi inversion) Ref MR696771 http://www.ams.org/mathscinet/pdf/696771.pdf (and no, it does not appear in either Wikipedia or PlanetMath, yet) is somewhat heuristic in character, suggesting : Transform the problem (T), Solve(S), Transform back(T^1), as a "bypass" given by (T^1)ST, which looks like conjugation. Melzak himself refers to adjoints (quite tangentially) as "being bypasses, though dressed up and served forth exotically" p.106 ibid. (I do recall that adjoints were generally seen as pretty exotic in the early 1970's when I was a graduate student at UBC, to my great chagrin). The MBP is acclaimed in MM vol.57 No.3 May 1984 as "a device for exploring analogies", or as "a dazzling attempt to comprehend complexity". Perhaps "bypass" could also be seen in the words of W.W. Tait (1996) "the propositions about the abstract objects translate into propositions about the things from which they are abstracted and, in particular, the truth of the former is founded on the truth of the latter". http://home.uchicago.edu/~wwtx/frege.cantor.dedekind.pdf . For me, "bypass" is a kenning for quasi-inverse or ad joint pairs. Motivation for seeking such a connection is not really to revive a 25 or 30 year old idea (as brilliant as Melzak's insights were, of course), but rather "to facilitate invention and discovery" (in Melzak's own words), and to find additional (as well as interdisciplinary) sources of instances of adjoints, possibly as a way to make adjoints more immediately relevant in any introductory discussion of categories, since, of course, adjoints are undoubtedly one of the most successful concepts within category theory. Further inspiration could be found in the Brown/Porter "Analogy" paper http://www.bangor.ac.uk/~mas010/eureka-meth1.pdf and others, along with a passion for invention and discovery through the continued pursuit of Unity and Identity of Opposites (UIO) - obviously referring to Bill Lawvere. Furthermore, I would also like to see this connection developed for practical reasons, applied to various situations, in particular to the structure of the www as an anthropomorphic creation that could benefit from further categorical perspective, given by the learned categorists I respect the most. I look forward to your thoughts and comments. ..... Al Al Vilcius Campbellville, ON, Canada

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FMCS 2008, Halifax - please register!
by selinger＠mathstat.dal.ca 29 Mar '08

29 Mar '08

FMCS 2008 16th Workshop on Foundational Methods in Computer Science Dalhousie University, Halifax, Canada May 30 - June 1, 2008 http://www.mathstat.dal.ca/~selinger/fmcs2008/ SECOND ANNOUNCEMENT: CALL FOR PARTICIPATION IMPORTANT DEADLINES: *** April 15 *** - please register to speak at the workshop. *** April 15 *** - to apply for student travel support * * * Foundational Methods in Computer Science is an annual workshop bringing together researchers in mathematics and computer science with a focus on the application of category theory in computer science. This year's meeting will be hosted in the Department of Mathematics and Statistics at Dalhousie University in Halifax, Canada. There will be an informal welcome reception in the evening of May 29. The scientific program starts on May 30, and consists of a day of tutorials aimed at students and newcomers to category theory, as well as a day and a half of research talks. The meeting ends at mid-day on June 1. FMCS 2008 takes place one week after MFPS 2008 (which will be held at the University of Pennsylvania). We hope that this will enable and encourage participants from overseas to attend both conferences! TUTORIAL LECTURES: There will be four tutorial lectures, presented by: Pieter Hofstra (Ottawa) Ernie Manes (Massachusetts) Paul-Andre Mellies (Paris 7) Andrea Schalk (Manchester) SPECIAL SESSION: There will be a special session in honor of Ernie Manes' 65th birthday. The special session will be organized by Phil Mulry. TO GIVE A TALK: Prospective speakers are requested to send a title and optional abstract to fmcs2008(a)mathstat.dal.ca by *** April 15 ***. Late submissions may be considered if there is space. All submissions will be acknowledged by return email. STUDENT SUPPORT: Graduate student participation is encouraged at FMCS. Students will pay a reduced registration fee. We will also be able to provide limited support for travel and accommodations to students. If you are interested in this, please send a request to fmcs2008(a)mathstat.dal.ca by *** April 15 ***. Please also arrange for a letter of reference from your supervisor or appropriate other person. ACCOMMODATIONS: We have reserved a block of rooms at the King's College residences. The rate, including taxes, are $37.37 per night for a single room, and $56.04 for a double room. Reservations can be made by sending an e-mail to conferences(a)admin.ukings.ns.ca and mentioning "FMCS 2008". A reservation form is available from the workshop website. It is preferred that you make your reservations by *** April 15 *** to ensure availability. For those wishing to stay in a hotel or bed & breakfast, some information is available on the conference website. REGISTRATION: Please register for the meeting by emailing fmcs2008(a)mathstat.dal.ca, preferably by *** April 15 ***. There will be an on-site registration fee of $120 to cover meeting costs. A discounted registration fee is available for students and for researchers without grant. MAPS AND LOCAL INFORMATION: Local information, including maps, is available from the conference website, http://www.mathstat.dal.ca/~selinger/fmcs2008/ PREVIOUS MEETINGS: Previous FMCS meetings were held in Pullman (1992), Portland (1993), Vancouver (1994), Kananaskis (1995), Pullman (1996), Portland (1998), Kananaskis (1999), Vancouver (2000), Spokane (2001), Hamilton (2002), Ottawa (2003), Kananaskis (2004), Vancouver (2005), Kananaskis (2006), and Hamilton (2007). ORGANIZING COMMITTEE: Robin Cockett (Calgary) John MacDonald (UBC) Phil Mulry (Colgate) Dorette Pronk (Dalhousie) Robert Seely (McGill) Peter Selinger (Dalhousie) LOCAL ORGANIZERS: Dorette Pronk (Dalhousie) Peter Selinger (Dalhousie) *

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MSFP second call for papers
by Venanzio Capretta 22 Mar '08

22 Mar '08

SECOND CALL FOR PAPERS This is a reminder that the deadline for submission to MSFP is approaching. Second Workshop on MATHEMATICALLY STRUCTURED FUNCTIONAL PROGRAMMING 6 July 2008, Reykjavik - Iceland A satellite workshop of ICALP 2008 PRESENTATION The workshop on Mathematically Structured Functional Programming is devoted to the derivation of functionality from structure. It is a celebration of the direct impact of Theoretical Computer Science on programs as we write them today. Modern programming languages, and in particular functional languages, support the direct expression of mathematical structures, equipping programmers with tools of remarkable power and abstraction. Monadic programming in Haskell is the paradigmatic example, but there are many more mathematical insights manifest in programs and in programming language design: Freyd-categories in reactive programming, symbolic differentiation yielding context structures, and comonadic presentations of dataflow, to name but three. This workshop is a forum for researchers who seek to reflect mathematical phenomena in data and control. The first MSFP workshop was held in Kuressaare, Estonia, in July 2006. An associated special issue of the Journal of Functional Programming is in preparation. INVITED SPEAKERS Andrej Bauer, University of Ljubljana Dan Piponi, Industrial Light and Magic SUBMISSIONS Electronic Notes in Theoretical Computer Science have provisionally agreed to publish the proceedings of MSFP 2008. ENTCS require submissions in LaTeX, formatted according to their guidelines (http://www.entcs.org/prelim.html) Papers must report previously unpublished work and not be submitted concurrently to another conference with refereed proceedings. Programme Committee members, barring the co-chairs, may (and indeed are encouraged to) contribute. Accepted papers must be presented at the workshop by one of the authors. There is no specific page limit, but authors should strive for brevity. We are using the EasyChair software to manage submissions. To submit a paper, please log in at: http://www.easychair.org/conferences/?conf=msfp2008. TIMELINE: Submission of abstracts: 4 April Submission of papers: 11 April Notification: 16 May Final versions due: 13 June Workshop: 6 July For more information about the workshop, go to: http://msfp.org.uk/ Programme Committee * Yves Bertot, INRIA, Sophia-Antipolis, France * Venanzio Capretta (co-chair), Radboud University, Nijmegen, The Netherlands * Jacques Carette, McMaster University, Hamilton, Ontario, Canada * Thierry Coquand, Chalmers University, Göteborg, Sweden * Andrzej Filinski, DIKU, University of Copenhagen, Denmark * Jean-Christophe Filliâtre, LRI, Université Paris Sud, France * Jeremy Gibbons, Oxford University, England * Andy Gill, Galois Inc., Portland, Oregon, USA * Peter Hancock, University of Nottingham, England * Oleg Kiselyov, FNMOC, Monterey, California, USA * Paul Blain Levy, University of Birmingham, England * Andres Löh, Utrecht University, The Netherlands * Marino Miculan, Università di Udine, Italy * Conor McBride (co-chair), Alta Systems, Northern Ireland * James McKinna, Radboud University, Nijmegen, The Netherlands * Alex Simpson, University of Edinburgh, Scotland * Tarmo Uustalu, Institute of Cybernetics, Tallinn, Estonia

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E. W. Beth Dissertation Prize: 2008 call for submissions
by Carlos Areces 22 Mar '08

22 Mar '08

E. W. Beth Dissertation Prize: 2008 call for submissions =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D Since 2002, FoLLI (the European Association for Logic, Language, and Information, www.folli.org) awards the E. W. Beth Dissertation Prize to outstanding dissertations in the fields of Logic, Language, and Information. We invite submissions for the best dissertation which resulted in a Ph.D. degree in the year 2007. The dissertations will be judged on technical depth and strength, originality, and impact made in at least two of the three fields of Logic, Language, and Computation. Inter-disciplinarity is an important feature of the theses competing for the E. W. Beth Dissertation Prize. Who qualifies ~~~~~~~~~~~~~ Nominations of candidates are admitted who were awarded a Ph.D. degree in the areas of Logic, Language, or Information between January 1st, 2007 and December 31st, 2007. There is no restriction on the nationality of the candidate or the university where the Ph.D. was granted. After a careful consideration, FoLLI has decided to accept only dissertations written in English. Dissertations produced in 2007 but not written in English or not translated will be allowed for submission, after translation, also with the call next year (for 2008). Respectively, nominations of full English translations of theses originally written in other language than English and defended in 2006 and 2007 will be accepted for consideration this year, too. Prize ~~~~~ The prize consists of: * a certificate * a donation of 2500 euros provided by the E. W. Beth Foundation. * an invitation to submit the thesis (or a revised version of it) to the new series of books in Logic, Language and Information to be published by Springer-Verlag as part of LNCS or LNCS/LNAI. (Further information on this series is available on the FoLLI site) How to submit ~~~~~~~~~~~~~ Only electronic submissions are accepted. The following documents are required: 1. the thesis in pdf or ps format (doc/rtf not accepted); 2. a ten page abstract of the dissertation in ascii or pdf format; 3. a letter of nomination from the thesis supervisor. Self-nominations are not admitted: each nomination must be sponsored by the thesis supervisor. The letter of nomination should concisely describe the scope and significance of the dissertation and state when the degree was officially awarded; 4. two additional letters of support, including at least one letter from a referee not affiliated with the academic institution that awarded the Ph.D. degree. All documents must be submitted electronically to bethaward2008(a)gmail.com. Hard copy submissions are not admitted. In case of any problems with the email submission or a lack of notification within three working days after submission, nominators should write to goranko(a)maths.wits.ac.za or policriti(a)dimi.uniud.it. Important dates ~~~~~~~~~~~~~~~ Deadline for Submissions: April 30th, 2008. Notification of Decision: July 15th, 2008. Committee : * Anne Abeill=C3=A9 (Universit=C3=A9 Paris 7) * Natasha Alechina (University of Nottingham) * Didier Caucal (IGM-CNRS) * Nissim Francez (The Technion, Haifa) * Valentin Goranko (chair) (University of the Witwatersrand, Johannesburg) * Alexander Koller (University of Edinburgh) * Alessandro Lenci (University of Pisa) * Gerald Penn (University of Toronto) * Alberto Policriti (Universit=C3=A0 di Udine) * Rob van der Sandt (University of Nijmegen) * Colin Stirling (University of Edinburgh)

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Submission deadline March 31 for QUANTUM PHYSICS AND LOGIC & DEVELOPMENTS IN COMPUTATIONAL MODELS, Reykjavik, Iceland, July 12-13, 2008
by Bob Coecke 21 Mar '08

21 Mar '08

ANNOUNCEMENT/CALL FOR CONTRIBUTIONS: --------------------------------------- Joint International Workshop on: QUANTUM PHYSICS AND LOGIC (QPL'08) DEVELOPMENTS IN COMPUTATIONAL MODELS (DCM'08) July 12-13, 2008, Reykjavik, Iceland. http://web.comlab.ox.ac.uk/oucl/work/bob.coecke/DCM_QPL_08.html --------------------------------------- Programme Committee: Howard Barnum (Los Alamos) Dan Browne (University College London) Bob Coecke (Oxford) Program Co-Chair Vincent Danos (Edinburgh) Andreas Doering (Imperial College London) Viv Kendon (Leeds) Annick Lesne (IHS Paris) Ian Mackie (LIX Paris) Prakash Panangaden (McGill) Program Co-Chair Jon Yard (Los Alamos) Invited speakers: Terry Rudolph (Imperial College London) Andreas Winter (Bristol) --------------------------------------- This ICALP 2008 affiliated joint event combines two (established) workshop series: QUANTUM PHYSICS AND LOGIC (QPL'08): This event has as its goal to bring together researchers working on mathematical foundations of quantum computing and the use of logical tools, new structures, formal languages, semantical methods and other computer science methods for the study quantum behaviour in general. Over the past couple of years there has been a growing activity in these foundational approaches together with a renewed interest in the foundations of quantum theory, which complement the more mainstream research in quantum computation. A predecessor of this event, with the same acronym, called Quantum Programming Languages, was held in Ottawa (2003), Turku (2004), Chicago (2005) and Oxford (2006); with the change of name and a new program committee we wish to emphasise the intended much broader scope of this event, aiming to nourish interaction between modern computer science logic, quantum computation and information, and structural foundations for quantum physics. DEVELOPMENTS IN COMPUTATIONAL MODELS (DCM'08): Besides quantum computing, several new models of computation have emerged in the last few years, and many developments of traditional computational models have been proposed with the aim of taking into account the new demands of computer systems users and the new capabilities of computation engines. A new computational model, or a new feature in a traditional one, usually is reflected in new structural paradigms. The aim of this workshop is to bring together researchers who are currently developing new computational models or new features for traditional computational models, in order to foster their interaction, to provide a forum for presenting new ideas and work in progress, and to enable newcomers to learn about current activities in this area. Previous editions in 2005, 2006 and 2007 were also affiliated to ICALP. Dates: - Submission deadline: March 31 - Acceptance/rejection notification: April 21 - Pre-proceedings versions due: June 15 - Workshop: July 12-13 2007 Submission format: Prospective speakers are invited to submit a 2-5 pages abstract which provides sufficient evidence of results of genuine interest and provides sufficient detail to allows the program committee to assess the merits of the work. Submissions of works in progress are encouraged but must be more substantial than a research proposal. We both encourage submissions of original research as well as research submitted elsewhere. Authors of accepted original research contributions will be invited to submit a full paper to a special issue of a journal yet to be decided on. Submissions should be in Postscript or PDF format and should be sent to Bob Coecke <coecke(a)comlab.ox.ac.uk> by March 31. Receipt of all submissions will be acknowledged by return email. Accepted contributors will be able to publish extended versions of their abstracts in Electronic Notes in Theoretical Computer Science. The workshop enjoys support from: EPSRC Network Semantics of Quantum Computation (EP/E006833/1) EPSRC ARF The Structure of Quantum Information and its Applications to IT (EP/D072786/1)

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a tentative answer to Paul
by Thomas Streicher 20 Mar '08

20 Mar '08

Dear Paul, I do have reveiled my meta-theory, namely ZFC together with the axiom that every set appears as element of some Grothendieck universe. This is not a question of belief but of convenience. I haven't found anything in category theory which needs expressivity beyond that. You ask what I mean by the validity of the statement \forall n:N \exists i : P(X_n)^{X_{n+1}} Iso(i) Well, it has to be read in the internal language of a topos augmented with some `macros' form the language of dependent types (here X -> N is some map in the topos and the formula specifies that it's the family P(N)_{n \in N}. Of course, one might take the pains of Kripke-Joyaling this internal statement BUT why should one want to do so. You are quite right in emphasizing that specifying such a family is one thing and its existence is another one. For the latter purpose one needs the eaxiom of replacement though possibly not its full strength. That's the motivation for my considerations in my "Universes in Toposes". Postulating a class of display maps SS with a strongly generic family E -> U (i.e. this map is in SS and all maps can be obtained as pullback of it) and some desired closure properties. Now supposing N \in U and U being closed under powerset P(-) its is a most simple exercise to construct a map f : N -> U with f(0) = N and f(n+1) = P(f(n)). We have just exploited that P restricts to a map U -> U. This is known since around 1970 when Martin-Loef introduced universes. Of course, he now would not consider something impredicative as the power set functor P but he would consider X \mapsto X^X as an operation on U. Apparently, quite a few category people are not that fond of universes in this sense. So one may ask the question to which extent one may express recursively defined families without universes. The answer given in Paul's book is to require initial fixpoints of endofunctors on some category of families. In case of the example above it would be an endofunctor on EE/N where EE is the topos under consideration. (See www.mathematik.tu-darmstadt.de/~streicher/itpowtop.pdf (temporary!) for one possible way of putting it.) Such an external handling of recursive family is certainly possible but I find it inconvenient because I want to construct my recursive families inside the internal language. In mathematics you never work externally but always internally, i.e. in one single unspecified formal system like ZFC or strengthenings of it (see above). "External" is a logician's idea who considers formal systems, their models and relations between them. But when doing mathematics it's not a good idea to "go external". Thomas PS I find interesting you comments about glueing and the necessity of replacement. I haven't come across this because on the meta-level I use a very strong system where I have it anyway. You are right that via glueing you get a consistency proof for HAH (higher order arithmetic). But this a priori doesn't require replacemnt since Zermelo set theory is sufficient for this purpose.

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Fundamenta Informaticae / Special issue / Machines, Computations and Universality
by jerome.durand-lose＠univ-orleans.fr 20 Mar '08

20 Mar '08

Call for paper for the special issue of Fundamenta Informaticae on "Machines, Computations and Universality". This call for paper is open to everyone (it is not restricted to the participant of MCU '07). After the success of MCU '07 at Orleans (France), in Sept. 10-13, 2007, a special issue of Fundamenta Informaticae will be published with contributions on the topics of the conference, which include the following: Digital computation (fundamental classical models): Turing machines, register machines, word processing (groups and monoids), other machines. Digital models of computation: cellular automata, other automata, tiling of the plane, polyominoes, snakes, neural networks, molecular computations, Analog and Hybrid Computations: BSS machines, infinite cellular automata, real machines, quantum computing, computable analysis, abstract geometrical computation. In all these settings: frontiers between a decidable halting problem and an undecidable one in the various computational settings minimal universal codes: size of such a code, namely, for Turing machines, register machines, cellular automata, tilings, neural nets, Post systems computation complexity of machines with a decidable halting problem as well as universal machines, connections between decidability under some complexity class and completeness according to this class, self-reproduction and other tasks, universality and decidability in the real field. Submissions will be refereed and here are the dates for the process: submission dead-line: April 10th, 2008 (strict) notification of accetance/rejection : September, 1st, 2008 final version due: December, 1st, 2008 If you already have a published contribution in the proceedings of the conference (LNCS 4664), we draw your attention on the following: your submission must be sustantially different from the paper of LNCS: it must either contain significantly new results or important proofs that could not be included in the LNCS format; we have to strictly apply this rule. Send your submission to the following address: margens(a)univ-metz.fr It is important that your submission applies FI's format (see FI's site: http://fi.mimuw.edu.pl/) for your contribution to be examined. There is no apriori limit on the number of pages. The format of FI is large and, in principle, 30 pages is a reasonable limit. If you actually need more,please contact us. Jerome Durand-Lose, Maurice Margenstern, co-chairs of MCU '07

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[gratra] ICGT 2008 - Call for Papers
by Reiko Heckel 20 Mar '08

20 Mar '08

[Please apologize if you receive multiple copies of this message.] Second Call for Papers ------------------------ 4th International Conference on Graph Transformation (ICGT 2008) Leicester, United Kingdom, September 7 - 13, 2008 ----------------------- The 4th International Conference on Graph Transformation (ICGT 2008) will be held in Leicester (United Kingdom) in the second week of September 2008, along with several satellite events. It continues the line of conferences previously held in Barcelona (Spain) in 2002, Rome (Italy) in 2004, and Natal (Brazil) in 2006 as well as a series of six International Workshops on Graph Transformation with Applications in Computer Science between 1978 and 1998, and alternates with the workshop series on Application of Graph Transformation with Industrial Relevance. The conference takes place under the auspices of EATCS, EASST, and IFIP WG 1.3. Awards will be given by EATCS and EASST for the best theoretical and application-oriented papers. Proceedings are planned with Springer's Lecture Notes in Computer Science series. Scope: Graphs are among the simplest and most universal models for a variety of systems, not just in computer science, but throughout engineering and the life sciences. When systems evolve we are interested in the way they change, to predict, support, or react to their evolution. Graph transformation combines the idea of graphs as a universal modelling paradigm with a rule-based approach to specify evolution. The area is concerned with both the theory of graph transformation and their application to a variety of domains. The conference aims at bringing together researchers and practitioners interested in the foundations and application of graph transformation to a variety of areas. Topics of interest include, but are not limited to * foundations and theory of o General models of graph transformatio o High-level and adhesive replacement systems o Node-, edge-, and hyperedge replacement grammars o Parallel, concurrent, and distributed graph transformations o Term graph rewriting o Hierarchical graphs and decompositions of graphs o Logic expression of graph transformation properties o Graph theoretical properties of graph languages o Geometrical and topological aspects of graph transformation o Automata on graphs and parsing of graph languages o Analysis and verification of graph transformation systems o Structuring and modularization concepts for transformation systems o Graph transformation and Petri nets * application to, languages and tool support for o Software architecture o Workflows and business processes o Software quality and testing o Software evolution o Access control and security models o Aspect-oriented development o Model-driven development, especially model transformations o Domain-specific languages o Implementation of programming languages o Bioinformatics and system biology o Natural computing o Image generation and pattern recognition techniques o Massively parallel computing o Self-adaptive systems and ubiquitous computing o Service-oriented applications and semantic web o Rule- and knowledge-based systems Submitted papers should not exceed fifteen (15) pages using Springer's LNCS format, and should contain original research. Simultaneous submission to other conferences with proceedings or submission of material that has already been published elsewhere is not allowed. Important Dates: Submission of title and abstract: April 10, 2008 Submission of complete paper: April 17, 2008 Notification of acceptance: May 15, 2008 Final version due: June 15, 2008 Main conference: September 10-12, 2008 Conference including satellite events: September 7-13, 2008 The following Satellite Events are planned: - Doctoral Symposium Contact: Andrea Corradini <andrea(a)di.unipi.it> - GCM: Workshop on Graph Computation Models Contact: Mohamed Mosbah <mosbah(a)labri.fr> - GraBaTs: Graph Transformation Tools Contest Contact: Arend Rensink <rensink(a)cs.utwente.nl> - Tutorial: Introduction to Graph Transformation Contact: Reiko Heckel <reiko(a)mcs.le.ac.uk> - PNGT: Petri Nets and Graph Transformations Contact: Paolo Baldan <baldan(a)dsi.unive.it> - NCTG: Natural Computing and Graph Transformation Contact: Grzegorz Rozenberg <rozenber(a)liacs.nl>, Ian Petre <ipetre(a)abo.fi> Venue: Located in the heart of England, Leicester is a truly multi-cultural city. The city is a historic meeting place, where for centuries people of different races and cultures have gathered, creating a rich and unique heritage. This diversity continues today with a thriving ethnic minority community accounting for more than a third of Leicester's population. ICGT 2008 will be held at the University of Leicester's conference facility next to the Universiy's botanic gardens. Organisation Program Chairs Reiko Heckel <reiko(a)mcs.le.ac.uk>, University of Leicester, United Kingdom Gabriele Taentzer <taentzer(a)mathematik.uni-marburg.de>, Philipps-Universität Marburg, Germany Local Organisation Reiko Heckel <reiko(a)mcs.le.ac.uk>, University of Leicester, United Kingdom Publicity Chair: Karsten Ehrig <karsten(a)mcs.le.ac.uk>, University of Leicester, United Kingdom Workshop Chair: Dénes Bisztray <dab24(a)mcs.le.ac.uk>, University of Leicester, United Kingdom PC members: # Paolo Baldan, Padova (Italy) # Luciano Baresi, Milano (Italy) # Michel Bauderon, Bordeaux (France) # Andrea Corradini, Pisa (Italy) # Hartmut Ehrig, Berlin (Germany) # Gregor Engels, Paderborn (Germany) # Annegret Habel, Oldenburg (Germany) # Reiko Heckel (co-chair), Leicester (UK) # Dirk Janssens, Antwerp (Belgium) # Garbor Karsai, Nashville (USA) # Barbara Koenig, Stuttgart (Germany) # Hans-Jörg Kreowski, Bremen (Germany) # Juan de Lara, Madrid (Spain) # Tom Mens, Mons (Belgium) # Mark Minas, München (Germany) # Ugo Montanari, Pisa (Italy) # Mohamed Mosbah, Bordeau (France) # Manfred Nagl, Aachen (Germany) # Fernando Orejas, Barcelona (Spain) # Francesco Parisi-Presicce, Rome (Italy) # Mauro Pezzè, Milano (Italy) # John Pfaltz, Charlottesville (Virginia, USA) # Rinus Plasmeijer, Nijmegen (The Netherlands) # Detlef Plump, York (UK) # Arend Rensink, Twente (The Netherlands) # Leila Ribeiro, Porto Alegre (Brasil) # Grzegorz Rozenberg, Leiden (The Netherlands) # Andy Schürr, Darmstadt (Germany) # Gabriele Taentzer (co-chair), Marburg (Germany) # Hans Vangheluwe, Montreal (Canada) # Dániel Varró, Budapest (Hungary) # Albert Zündorf, Kassel (Germany) Further Information can be found at: http://www.cs.le.ac.uk/events/icgt2008 -- ------------------------------------------ Prof. Dr. Gabriele Taentzer Philipps-Universität Marburg Fachbereich Mathematik und Informatik Hans-Meerwein-Str. D-35032 Marburg Phone: +49-6421-2821532 Email: taentzer(a)mathematik.uni-marburg.de ------------------------------------------

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A question on adjoints
by Michael Barr 20 Mar '08

20 Mar '08

I guess I am getting old and dumb. This question should have been a snap for me years ago. It is old fashioned, only a 1-categorical question and not about internal vs. external. Suppose F: A --> B is left adjoint to U: B --> A. Suppose a is an object of A and b, b' objects of B such that there is an equalizer a ---> Ub ===> Ub'. (The two arrows Ub to UB' are not assumed to be U of arrows from B.) Does it follow that a ---> UFa ===> UFUFa is an equalizer? The arrows are \eta a, UF\eta a and \eta UFa of course. Michael

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