December 2001 - Categories - categories.org.au

Only two SMC structures on Cat?
by Jason C Reed 27 Jul '02

27 Jul '02

Power, A.J. and Robinson, E.P. Premonoidal categories and notions of computation (ftp://ftp.dcs.qmw.ac.uk/pub/lfp/edmundr/premoncat.ps.gz) in section 2 asserts that there is excatly one symmetric monoidal closed structure on Cat besides the cartesian one. Does anyone know [the location of] a proof? ---Jason

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paperback announcement: Categorical Logic and Type Theory
by Bart Jacobs 16 Mar '02

16 Mar '02

Dear Colleague, I am happy to announce that Elsevier has now published a paperback version of my book B. Jacobs, Categorical Logic and Type Theory Studies in Logic and the Foundations of Mathematics 141, North Holland, Elsevier, 1999. 780 pages. The regular price of the paperback is NLG 150 / Euro 68.07 / US$ 74 Elsevier now offers a discount of 25% for this paperback if you order before 31 july 2001, using the attached form. In that case the price is: NLG 112.50 / Euro 51 / US$ 55.50. If you wish to use this special offer, please fill in the form, and send it in time to Andy Deelen at Elsevier (precise address at bottom of the form). Do not send it to me. The book gives a survey of categorical logic and type theory starting from the unifying concept of a fibration. Its intended audience consists of logicians, type theorists, category theorists and (theoretical) computer scientists. It contains the following chapters. Prospectus Introduction to fibred category theory Simple type theory Equational Logic First order predicate logic Higher order predicate logic The effective topos Internal category theory Polymorphic type theory Advanced fibred category theory First order dependent type theory Higher order dependent type theory References Notation index Subject index More information can be obtained from the authors webpage: http://www.cs.kun.nl/~bart/CLT/bookinfo.html Bart Jacobs, Dep. Comp. Sci., Univ. Nijmegen, P.O. Box 9010, 6500 GL Nijmegen, The Netherlands. Email: bart(a)cs.kun.nl PS. Please pass this information on to your institute's librarian.

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Positions in Paris 7 University
by Pierre-Louis Curien 01 Feb '02

01 Feb '02

Universite Paris 7 - CNRS Laboratoire d'Informatique Algorithmique : Fondements et Applications (LIAFA) Laboratoire Preuves,, Programmes et Systemes (PPS) APPEL A CANDIDATURES / ANNOUNCEMENT Il y aura au concours 2002 / University Paris 7 will hire in 2002 - 2 postes de professeur d'universite / 2 professors - 3 postes de maitres de conferences / 3 assistant professors en informatique / in computer science. La recherche en informatique est repartie sur deux laboratoires / There are two computer science laboratories at Paris 7: - LIAFA (algorithms and combinatorics, automata, modelisation and verification) - PPS (logic and programming) Les deux laboratoires souhaitent renforcer et elargir leurs thematiques / Both laboratories seek to reinforce and enlarge their research themes. Profils recherches / some possible research profiles for applicants - tous les domaines de competence actuels des deux laboratoires / all present themes of LIAFA and PPS - LIAFA: bases de donnees, bio-informatique, cryptographie, ingenierie de la langue, systemes a evenements discrets / data bases, bio-informatics, cryptography, computational linguistics, discrete event systems - PPS: nous recherchons une ouverture sur les objets, ainsi que sur concurrence et mobilite / we seek expertise on objects, and on mobility and concurrency Application information: The positions will be officially open for application in early 2002. Only candidates who have gone through the national Qualification procedure (application during the autumn of year n for applying to a position in year n+1) are eligible. Rather fluent knowledge of French is expected for teaching. The five positions are permanent positions, starting october 2002. Pour plus d'information sur les deux laboratoires / URL links of the two labs http://www.liafa.jussieu.fr http://www.pps.jussieu.fr Contact : Daniel KROB - Directeur du LIAFA - dk(a)liafa.jussieu.fr Pierre-Louis CURIEN - Directeur de PPS - curien(a)pps.jussieu.fr

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Categories and cognition
by Andree Ehresmann 11 Jan '02

11 Jan '02

In answer to >I simply want to attract category theorists to cognitive science. May I refer to the mathematical model for biological and neural systems, based on category theory, which I am developing with a physician, Jean-Paul Vanbremeersch, since 15 years? It uses categorical tools, e.g. completion theorems, for explaining the emergence of higher order cognitive processes and the formation of a Semantics (possibly without necessarily language). The main ideas as well as some recent papers and the list of our publications can be found in our Internet site: http://perso.wanadoo.fr/vbm-ehr With my best wishes for the new year Andree C. Ehresmann

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Natural disasters
by Michael Barr 07 Jan '02

07 Jan '02

It seems like there are natural disasters, first in Sydney and, to a lesser extent, in Buffalo (82 inches of snow by one report) and I would like to enquire how all are. Michael

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Two categories or 2-categories?
by Peter Freyd 02 Jan '02

02 Jan '02

In the film "A Beautiful Mind," the first indication that John Nash is regaining his abilities is a conversation with a student ("Galois extensions are really the same as covering spaces!" exclaims Toby, the student). The scene ends with Nash and the student bent over some papers and -- as I heard it -- the student says: "Functor...Two...Categories" (The film's not bad but its relation to Nash's life is tangential. If I had not absorbed a hint from a review, I think I might have stomped out in the middle because of the ridiculous portrayal of what mathematicians do. It turns out that the filmmakers are playing a game -- very effective with most of the audience -- in sliding between perceptions: ours and Nash's.)

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New address: RFC Walters
by RFC Walters 31 Dec '01

31 Dec '01

New email address robert.walters(a)uninsubria.it New mail address Universita' dell'Insubria Dipartimento di Scienze CC, FF e MM Via Valleggio 11 22100 COMO, Italy Web homepage http://www.unico.it/~walters/ My recent papers are available there: the latest being P. Katis, N. Sabadini, R.F.C. Walters Feedback, trace and fixed point semantics We introduce a notion of category with feedback-with-delay, closely related to the notion of traced monoidal category, and show that the Circ construction of [JPAA 115: 141--178, 1997] is the free category with feedback on a symmetric monoidal category. Combining with the Int construction of Joyal-Street-Verity [Math. Proc. Camb.Phil. Soc., 119, 447-468, 1996] we obtain a description of the free compact closed category on a symmetric monoidal category. We thus obtain a categorical analogue of the classical localization of a ring with respect to a multiplicative subset. In this context we define a notion of fixed-point semantics of a category with feedback which is seen to include a variety of classical semantics in computer science. Others: R. Rosebrugh, N. Sabadini, R. F. C. Walters, Minimization and Minimal Realization in Span(Graph), submitted P. Katis, N. Sabadini, RFC Walters, Classes of finite state automata for which compositional minimization is linear time Fabio Gadducci, Piergiulio Katis, Ugo Montanari, Nicoletta Sabadini, Robert F.C. Walters, Comparing cospan-spans and tiles via a Hoare-style process calculus

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Enriched locally presentable categories
by Mark Hovey 31 Dec '01

31 Dec '01

I am still trying to understand some enriched category theory. Suppose V is a closed symmetric monoidal category that is also locally presentable. Suppose C is a small V-category. I am interested in the category of V-functors from C to V, and, in particular, I want to know that it is locally presentable. Might need some hypotheses on C for this, but I would prefer to avoid hypotheses on the actual functors. This time I have actually looked in Kelly's book and I did not see it, but I confess to finding this subject rough going so might have missed it. On the other hand, my library is closed for the holiday, so I have not looked at Adamek and Rosicky's book on enriched category theory yet. I guess the generators ought to be the representable functors. I know everything is a weighted colimit of representables, but I don't know whether this colimit is filtered enough, nor do I know whether one can get away with weighted colimits instead of ordinary ones. One direction this might go is to develop a theory of locally presentable in an enriched sense, using weighted colimits instead of colimits. I would prefer to avoid that if possible. Happy holidays to all. Mark Hovey

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CFP: AMAST'2002
by Christophe Ringeissen 22 Dec '01

22 Dec '01

[We apologize if you receive multiple copies of this message] AMAST 2002 CALL FOR PAPERS 9-th International Conference on Algebraic Methodology And Software Technology AMAST 2002, September 9-13, 2002 St. Gilles les Bains, Reunion Island, France * Important Dates: Paper submissions February 1, 2002 Notification of paper acceptance April 27, 2002 Camera ready papers June 1, 2002 AMAST 2002 conference September 9-13, 2002 * Topics: As in previous years, we invite papers reporting original research on setting software technology on a firm mathematical basis. Of particular interest is research on using algebraic, logic, and other formalisms suitable as foundations for software technology, as well as software technologies developed by means of logic and algebraic methodologies. * Submissions: We invite prospective authors to submit electronically previously unpublished papers of high quality. Papers must be no longer than 15 pages (6 pages for system demonstrations) and should be prepared using LaTeX and the LNCS style that can be downloaded from the URL: http://www.springer.de/comp/lncs/authors.html Please send a fully self-contained PostScript file to amast(a)loria.fr As in the past, the AMAST'2002 proceedings will be published by Springer-Verlag in the Lecture Notes in Computer Science Series. * Program Committee: V.S. Alagar, E. Astesiano, M. Bidoit, D. Bolignano, M. Broy, J. Fiadeiro, B. Fischer, K. Futatsugi, A. Haeberer, N. Halbwachs, A. Haxthausen, D. Hutter, P. Inverardi, B. Jacobs, M. Johnson, H. Kirchner (PC chair), P. Klint, T. Maibaum, Z. Manna, J. Millen, P. Mosses, F. Orejas, R. de Queiroz, T. Rus, C. Ringeissen (PC chair assistant), D. Sannella, P.-Y. Schobbens, G. Scollo, A. Tarlecki, M. Wirsing * Local Organization Chair: Teodor Knapik, Univ. de la Reunion * Further information: For regularly updated details of the conference organization send email to amast(a)loria.fr or visit the AMAST'2002 web page: http://www.loria.fr/conferences/amast2002

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language and thinking
by Posina Venkata Rayudu 21 Dec '01

21 Dec '01

Hi, Does the debate -elements and their belongingness vs. functions and their composition- support Sapir-Whorf hypothesis that the way we think is a function of the language we use. In other words, language can transform thinking. According to this doctrine of linguistic relativity, =93users of markedly different grammars are pointed by their grammars toward different types of observations=85and hence are not equivalent as observers, but must arrive at somewhat different views of the world=94 (Whorf 1956, p. 221). Whorf, B. L. (1956) Language, Thought, and Reality: Selected Writings of Benjamin Lee Whorf (ed. J. B. Carroll) MIT Press, Cambridge, MA. Thanking you, Sincerely, Posina Venkata Rayudu =3D=3D=3D=3D=3D Posina Venkata Rayudu C/o: Sri. S. S. Chalam Advocate & Notary Public H.No: 39-4-10, Innespeta Rajahmundry =96 533102 Andhra Pradesh, India Phone: 91 (0883) 444232

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