From cat-dist Mon Jun 2 09:11:06 1997 Received: by mailserv.mta.ca; id AA02683; Mon, 2 Jun 1997 09:10:20 -0300 Date: Mon, 2 Jun 1997 09:10:20 -0300 (ADT) From: categories To: categories Subject: CTCS'97 - Call for Participation Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: O X-Status: Date: Sat, 31 May 1997 15:28:10 +0200 From: Eugenio Moggi [Please look at the conference URL for more detailed information] CATEGORY THEORY AND COMPUTER SCIENCE (CTCS'97) 4-6 SEPTEMBER 1997, S. MARGHERITA LIGURE (GENOA), ITALY CONFERENCE URL: "http://www.disi.unige.it/conferences/ctcs97/" PRELIMINARY PROGRAMME and CALL FOR PARTICIPATION CTCS'97 is the 7th conference on Category Theory and Computer Science. The purpose of the conference series is the advancement of the foundations of computing using the tools of category theory, algebra, geometry and logic. While the emphasis is upon applications of category theory, it is recognized that the area is highly interdisciplinary. The proceedings will be published by Springer in the LNCS series. The conference is sponsored by GNIM (Gruppo Nazionale Informatica Matematica) of CNR and Universita' di Genova. LOCATION The conference will take place at Hotel Regina Elena, a 4 stars hotel with private beach, located in S. Margherita Ligure. S. Margherita is a beautiful sea resort in Liguria very close to Portofino promontory and about 30 km east of Genova. INVITED SPEAKERS - J. Baez, Univ. of California at Riverside (USA) - R. Bird, Oxford Univ. (UK) - B. Jay, Univ. of Technology Sydney (Australia) - G. Plotkin, Univ. of Edinburgh (UK) ************************ IMPORTANT DEADLINES ************************ **** 15 JULY 1997 early registration **** **** 31 JULY 1997 "guaranteed" hotel reservation **** ********************************************************************* REGISTRATION. See the CONFERENCE URL for details on how to register. | before 15 July | after 15 July | -----------------------------------------------| Regular rate | 260000 It.Lire | 400000 It.Lire | -----------------------------------------------| Student rate | 220000 It.Lire | 400000 It.Lire | ------------------------------------------------ The fee includes the welcome reception, coffee breaks, lunches, a copy of the proceedings. HOTEL RESERVATION. Hotel reservations are handled by DAVOR VIAGGI (see the CONFERENCE URL for details). Participants will be hosted in 3 and 4 stars hotels (among them the conference hotel). All hotels are within walking distance from the conference hotel and have rooms with private bathrooms. The price range of a room per day inclusive of breakfast and taxes are | single room | double/twin room | --------------------------------------------------------| 4 stars | 113000-138000 It.Lire | 178000-242000 It.Lire | --------------------------------------------------------| 3 stars | 75000-115000 It.Lire | 120000-155000 It.Lire | --------------------------------------------------------- Requests are handled on a first-come-first-served basis, therefore it is advisable to send the hotel registration form well before the deadline. After JULY 31 DAVOR VIAGGI will accept reservations, but can no longer guarantee that they can be satisfied. CONTACT INFORMATION - Conference email: ctcs97@disi.unige.it fax: +39 (10) 3536699 - Address: E. Moggi (CTCS'97), DISI, v. Dodecaneso 35, 16146 Genova, Italy - Organizers: E. Moggi, moggi@disi.unige.it, +39 (10) 353 6629 G. Rosolini, rosolini@disi.unige.it, +39 (10) 353 6630 PROGRAMME COMMITTEE S. Abramsky (UK) P.-L. Curien (France), P. Dybjer (Sweden), P. Johnstone (UK), G. Longo (France), G. Mints (USA), J. Mitchell (USA), E. Moggi (Italy), A. Pitts (UK), A. Poigne (Germany), G. Rosolini (Italy), D. Rydeheard (UK), F-J. de Vries (Japan). RELATED EVENTS Express'97 workshop, 8-12 Sep 1997, S. Margherita Ligure, Italy. ----------------------------------------------------------------------------- PRELIMINARY PROGRAMME HOTEL REGINA ELENA Lungomare Milite Ignoto 44, 16038 S. Margherita Ligure, Italy phone: +39 (185) 287003, fax: +39 (185) 284473 WEDNESDAY, 3 September 18.00 Welcome Reception and Registration THURSDAY, 4 September 09.00 Invited Talk: Richard Bird 10.15 Coffee Break 10.40 Proof Principles for Datatypes with Iterated Recursion by Ulrich Hensel, Bart Jacobs 11.20 A Calculus for Collections and Aggregates by Kazem Lellahi, Val Tannen 12.00 When do datatypes commute? by Paul Hoogendijk, Roland Backhouse 12.40 Lunch 14.45 Invited Talk: John Baez 16.00 Coffee Break 16.30 A factorisation theorem for external derivations by Paul-Andre Mellies 17.10 Monads and Modular Term Rewriting by Christoph Lueth, Neil Ghani 17.50 A 2-Categorical Presentation of Term Graph Rewriting by Andrea Corradini, Fabio Gadducci FRIDAY, 5 September 09.00 Invited Talk: Barry Jay 10.15 Coffee Break 10.40 Presheaf Models for the pi-Calculus by Gian Luca Cattani, Ian Stark, Glynn Winskel 11.20 Categorical Modelling of Structural Operational Rules: case studies by Daniele Turi 12.00 Specifying Interaction Categories by Dusko Pavlovic, Samson Abramsky 12.40 Lunch 14.45 Invited Talk: Gordon Plotkin 16.00 Coffee Break 16.30 Lifting by A. Bucalo, G. Rosolini 17.10 General Synthetic Domain Theory -- A Logical Approach by Bernhard Reus, Thomas Streicher 17.50 Discussion on CTCS 20.00 Conference Dinner SATURDAY, 6 September 09.00 Shedding New Light in the World of Logical Systems by Uwe Wolter, Alfio Martini 09.40 Combining and Representing Logical Systems by Till Mossakowski, Andrzej Tarlecki, Wieslaw Pawlowski 10.20 Coffee Break 10.50 A decision algorithm for linear isomorphism of types O(nlog^2n) by Alexander Andreev, Sergei Soloviev 11.30 Effectiveness of the Global Modulus of Continuity on Metric Spaces by Klaus Weihrauch, Xizhong Zheng 12.30 Lunch Free Afternoon ----------------------------------------------------------------------------- From cat-dist Mon Jun 2 09:11:11 1997 Received: by mailserv.mta.ca; id AA02493; Mon, 2 Jun 1997 09:09:13 -0300 Date: Mon, 2 Jun 1997 09:09:13 -0300 (ADT) From: categories To: categories Subject: ANNOUNCING: Xy-pic version 3.5 released! Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: O X-Status: Date: Fri, 30 May 1997 11:51:51 +0200 (MET DST) From: Kristoffer Hogsbro Rose Dear Category Theorists, Please find enclosed a copy of the TRAILER for a new version of Xy-pic - I am sorry for announcing a new version so soon after the previous release but a serious bug needed fixing. I hope you will find this version useful. Sincerely, Kristoffer H. Rose PS. Notice that DIKU has discontinued my ftp directory, so the European home of Xy-pic is now at brics.dk; as usual the mirror at CTAN should be current in a few days. ======================================================================= ANNOUNCING the Xy-pic version 3.5 DIAGRAM TYPESETTING PACKAGE ======================================================================= This is to announce a release of my diagram typesetting package Xy-pic. version 3.5 is a bug fix release where a single serious bug of the previous major release of Xy-pic 3 has been eliminated. ----------------------------------------------------------------------- GENERAL ----------------------------------------------------------------------- Xy-pic is a package for typesetting a variety of graphs and diagrams with TeX. Xy-pic works with most formats (including LaTeX, AMS-LaTeX, AMS-TeX, and plain TeX), in particular Xy-pic is provided as a LaTeX2e `supported package' (following the `CTAN LaTeX2e bundle' standard). Further specifics of the package are in the distribution README file. ----------------------------------------------------------------------- NEWS ----------------------------------------------------------------------- Xy-pic version 3 was a thorough rewrite of the prior major version, version 2 (last version 2 release was release 2.6; several beta-test releases of version 3, numbered 2.7-2.12, were made available to users). However, full backwards compatibility is maintained (except for the unavoidable but fully documented obscure cases). Release 3.5 fixes the following problem of release 3.4: * Breaks (in arrows) were ignored more often than not! Furthermore version 3.5 adds an installation script for TDS-compliant un*x Xy-pic installations. Thanks to Uffe Engberg, Juan Carlos Soliveres, and John Landamore for your bug reports! ----------------------------------------------------------------------- AVAILABILITY ----------------------------------------------------------------------- Xy-pic can be retrieved through the World Wide Web Xy-pic `home pages': URL: http://www.brics.dk/~krisrose/Xy-pic.html URL: http://www.mpce.mq.edu.au/~ross/Xy-pic.html as well as by anonymous ftp from CTAN: macros/generic/diagrams/xypic and from the private archives of the authors: ftp.brics.dk : /Staff/krisrose/TeX/ ftp.mpce.mq.edu.au : /pub/maths/TeX/ Check the README file in each location for specifics, in particular check that you have reached a version 3.5 copy (some archives take a while to mirror the latest files)! ----------------------------------------------------------------------- HISTORY & CREDITS ----------------------------------------------------------------------- The first public release (version 1.40) of Xy-pic was created by Kristoffer H. Rose, DIKU, U of Copenhagen (now BRICS, U of Aarhus) and distributed via Usenet on December 19, 1991. (Version 3.3 was released on December 19, 1996 because this was the fifth anniversary of Xy-pic.) This quickly became Version 2 of which version 2.6 was the most stable. The rewrite that became version 3 is a continued collaboration with Ross Moore, Macquarie U, Sydney, initiated through a visit to Macquarie (Jan-May 1994 supported by the Australian Research Council, Macquarie University, and using donated DEC equipment). Xy-pic is Copyright (c) 1991-1997 by Kristoffer H. Rose and 1994-1997 by Ross Moore under GNU COPYLEFT which means that you can use the package for any purpose but if you provide the macros or any code derived from them to a third party then you are obliged to include the entire Xy-pic package (full details in the file COPYING). ----------------------------------------------------------------------- This is the end of the announcement. Enjoy Xy-pic! ----------------------------------------------------------------------- PS. Don't miss TUG'97 with the latest in advanced TeX/LaTeX web & math typesetting developments! See -- Kristoffer Hxgsbro ROSE, Ph.D. BRICS International Ph.D. School Department of Computer Science +45 89423193, 20900180, fax 89423255 University of Aarhus, Ny Munkegade, bld. 540, DK-8000 Erhus C, DENMARK From cat-dist Tue Jun 3 11:06:59 1997 Received: by mailserv.mta.ca; id AA18011; Tue, 3 Jun 1997 11:05:30 -0300 Date: Tue, 3 Jun 1997 11:05:30 -0300 (ADT) From: categories To: categories Subject: New versions of papers available Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: O X-Status: Date: Mon, 02 Jun 1997 15:18:51 -0400 From: Charles Wells New versions of three papers by Atish Bagchi and myself are available at http://www.cwru.edu/CWRU/Dept/Artsci/math/wells/pub/papers.html The papers are Varieties of Mathematical Prose Graph Based Logic and Sketches I: The General Framework Graph Based Logic and Sketches II: Finite Product Categories and Equational Logic Charles Wells, 105 South Cedar Street, Oberlin, Ohio 44074, USA. EMAIL: cfw2@po.cwru.edu. HOME PHONE: 216 774 1926. FAX: Same as home phone. HOME PAGE: URL http://www.cwru.edu/CWRU/Dept/Artsci/math/wells/home.html "Some have said that I can't sing. But no one will say that I _didn't_ sing." --Florence Foster Jenkins From cat-dist Mon Jun 9 12:38:27 1997 Received: by mailserv.mta.ca; id AA31472; Mon, 9 Jun 1997 12:38:05 -0300 Date: Mon, 9 Jun 1997 12:38:05 -0300 (ADT) From: categories To: categories Subject: Call for papers - BarrFest Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: O X-Status: Date: Mon, 9 Jun 1997 10:01:42 -0400 From: Robert A. G. Seely CENTRE de RECHERCHE en THEORIE des CATEGORIES CATEGORY THEORY RESEARCH CENTER C ---------> R | / | | / | | / | | / | v / v T ---------> C BARRFEST PROCEEDINGS - CALL FOR PAPERS There will be a special issue of the Journal of Pure and Applied Algebra dedicated to Michael Barr, in honour of his 60th birthday, and nominally the proceedings of the BarrFest, held in Montreal 29 - 31 May 1997. We invite submissions to these Proceedings from anyone interested; papers submitted will undergo the usual JPAA referee process, and we are hopeful that the final Proceedings will be ready before summer 1998. Topics suitable for the Proceedings include any of the subjects to which Michael Barr has contributed, such as homological algebra, triples, embeddings, exact catgeories, torsion theories, topos theory, topology, *-autonomous categories, universal algebra, logic, linear logic, computer science, or linguistics. The submission deadline for the BarrFest Proceedings is 15 September 1997. Please send five (5) (paper) copies before then to R.A.G. Seely Department of Mathematics McGill University 805 Sherbrooke St W Montreal H3A 2K6 Quebec, Canada (If possible) please send an email message to rags@math.mcgill.ca indicating the title (and authors, if other than the sender of the email) of the paper, as well as an abstract (in standard ascii format, maximum 1 page) of the paper. If you are able to provide a uuencoded, compressed PostScript file (300 dpi), please mention this in your email as well. If having the electronic file will speed up the refereeing process, we will get in touch with you to request such files. For further information, please contact Robert Seely . F.W. Lawvere (guest editor) T. Fox, R.A.G. Seely (co-editors) From cat-dist Mon Jun 9 12:38:36 1997 Received: by mailserv.mta.ca; id AA31394; Mon, 9 Jun 1997 12:36:50 -0300 Date: Mon, 9 Jun 1997 12:36:50 -0300 (ADT) From: categories To: categories Subject: Tentative timetable, Billfest Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: O X-Status: Date: Sat, 7 Jun 1997 11:45:30 -0400 From: Michael Barr We now have a tentative timetable for the Billfest in Sept., although not very many titles. There will be a tex version, followed by an Ascii version. \documentstyle[12pt]{article} \textwidth 6.3in \oddsidemargin -.1in \begin{document} \begin{tabular}{|r@{--}r|l|p{3.4in}|}\hline \multicolumn4{|c|}{Friday, September 26\vrule height 15pt depth 5pt width 0pt}\\ \hline \multicolumn2{|c|}{} && \\[-10pt]\hline 8:45 & 9:35 &Andr\'e Joyal & TBA \\ \hline 9:45 & 10:15 &Marta Bunge &Functions vs Distributions\\ \hline 10:25 & 10:55 &Jonathon Funk &Complete Spreads in Topos Theory\\ \hline \multicolumn2{|c|}{} && \\[-12pt]\hline 3:00 & 3:50 &Pierre Cartier & TBA \\ \hline 4:00 & 4:30 &Phil Mulry & TBA \\ \hline 4:40 & 5:10 &Jim Otto & From NNO to Complexity \\ \hline 5:20 & 5:50 &Robert Par\'e & TBA \\ \hline \multicolumn4{|c|}{Saturday, September 27\vrule height 15pt depth 5pt width 0pt}\\ \hline \multicolumn2{|c|}{} && \\[-10pt]\hline 8:45 & 9:35 &Bill Lawvere & Toposes of Laws of Motion\\ \hline 9:45 & 10:15 &Walter Noll & TBA \\ \hline 10:25 & 10:55 &Anders Kock & TBA \\ \hline \multicolumn2{|c|}{} && \\[-12pt]\hline 3:00 & 3:50 &Peter Gabriel & TBA \\ \hline 4:00 & 4:30 &Alex Heller & TBA \\ \hline 4:40 & 5:10 &Kimmo Rosenthal& Multirelations and power quantales \\ \hline 5:20 & 5:50 &Fred Linton& Triples vs. Theories---one last time\\ \hline \multicolumn4{|c|}{Sunday, September 28\vrule height 15pt depth 5pt width 0pt}\\ \hline \multicolumn2{|c|}{} && \\[-10pt]\hline 8:45 & 9:35 &Mikhail Kapranov & TBA \\ \hline 9:45 & 10:15 &Ross Street & The Petit Topos of Globular Sets\\ \hline 10:25 & 10:55 &Todd Trimble & TBA \\ \hline \multicolumn2{|c|}{} && \\[-12pt]\hline 3:00 & 3:50 &Steve Schanuel & TBA \\ \hline 4:00 & 4:30 &Aurelio Carboni & TBA \\ \hline 4:40 & 5:10 &Jim Lambek &A tribute to Bill Lawvere \\ \hline \end{tabular} \end{document} |=======================================================================| | Friday, September 26 | |=======================================================================| |=======================================================================| | 8:45- 9:35| Andr\'e Joyal | TBA | |------------|---------------------|------------------------------------| | 9:45-10:15| Marta Bunge | Functions vs Distributions | |------------|---------------------|------------------------------------| | 10:25-10:55| Jonathon Funk | Complete Spreads in Topos Theory | |============|=====================|====================================| | 3:00- 3:50| Pierre Cartier | TBA | |------------|---------------------|------------------------------------| | 4:00- 4:30| Phil Mulry | TBA | |------------|---------------------|------------------------------------| | 4:40- 5:10| Jim Otto | From NNO to Complexity | |------------|---------------------|------------------------------------| | 5:20- 5:50| Robert Par\'e | TBA | |=======================================================================| | | | | |=======================================================================| | Saturday, September 27 | |=======================================================================| |=======================================================================| | 8:45- 9:35| Bill Lawvere | Toposes of Laws of Motion | |------------|---------------------|------------------------------------| | 9:45-10:15| Walter Noll | TBA | |------------|---------------------|------------------------------------| | 10:25-10:55| Anders Kock | TBA | |============|=====================|====================================| | 3:00- 3:50| Peter Gabriel | TBA | |------------|---------------------|------------------------------------| | 4:00- 4:30| Alex Heller | Multirelations and power quantales | |------------|---------------------|------------------------------------| | 4:40- 5:10| Kimmo Rosenthal | TBA | |------------|---------------------|------------------------------------| | 5:20- 5:50| Fred Linton |Triples vs. Theories--one last time | |=======================================================================| | | | | |=======================================================================| | Sunday, September 28 | |=======================================================================| |=======================================================================| | 8:45- 9:35| Mikhail Kapranov | TBA | |------------|---------------------|------------------------------------| | 9:45-10:15| Ross Street | The Petit Topos of Globular Sets | |------------|---------------------|------------------------------------| | 10:25-10:55| Todd Trimble | TBA | |============|=====================|====================================| | 3:00- 3:50| Steve Schanuel | TBA | |------------|---------------------|------------------------------------| | 4:00- 4:30| Aurelio Carboni | TBA | |------------|---------------------|------------------------------------| | 4:40- 5:10| Jim Lambek | A tribute to Bill Lawvere | |=======================================================================| From cat-dist Mon Jun 9 12:39:25 1997 Received: by mailserv.mta.ca; id AA31565; Mon, 9 Jun 1997 12:39:23 -0300 Date: Mon, 9 Jun 1997 12:39:23 -0300 (ADT) From: categories To: categories Subject: BarrFest "entertainments" Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: RO X-Status: Date: Mon, 9 Jun 1997 10:05:58 -0400 From: Robert A. G. Seely As advertised at the BarrFest, we have put several items on our ftp site of a lighter nature - namely Fred Linton's triples ode and presentation, Cynthia Kennison's short story "Closed door", and Saunder's "Here's to Barr". THese may be found by going to the Category group's home page at (these are identical at present). The call-for-papers notice may be found there as well. all the best, Robert Seely From cat-dist Wed Jun 11 11:52:20 1997 Received: by mailserv.mta.ca; id AA29877; Wed, 11 Jun 1997 11:51:11 -0300 Date: Wed, 11 Jun 1997 11:51:11 -0300 (ADT) From: categories To: categories Subject: CT97 Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: RO X-Status: Date: Mon, 9 Jun 97 17:59:24 -0700 From: John MacDonald INTERNATIONAL CATEGORY THEORY MEETING (CT97) July 13-19, 1997 University of British Columbia Vancouver, Canada The conference arrival day is Sunday July 13 with a reception 6-9pm in the Fireplace Lounge of Walter Gage Towers on the UBC campus. The scientific program will begin Monday morning July 14 at 9am in Angus 104 and will finish on Saturday July 19 at the end of the morning session (12:30pm). HOUSING On June 13 all rooms from our block which have not been individually reserved will be released to the public for reservation. After that time rooms can be reserved using the same reservation form anytime up until the start of the conference, as long as space is available. If you need a housing form, then please send email to johnm@math.ubc.ca with the subject Housing and a room reservation form will be sent to you. The completed form can then be sent by email to the housing office. REGISTRATION It is not too late to register for the conference. In fact the organizers will welcome registrations up until one week before the meeting. To get a registration form please send email to johnm@math.ubc.ca with subject Registration. If you decide to come, then it will be greatly appreciated if you register as soon as possible after deciding so that our space requirements can be more accurately determined. SCIENTIFIC PROGRAM The number of speakers already appears to match the time available. For this reason it is unlikely that there will be time available on the program for those who have not already given the organizers a title or at least indicated their wish for a space on the program. A list of speakers will be sent out soon. TRAVEL AND TOURS The name and fax number of a Vancouver travel agent will be supplied upon request to those who wish to book a hotel or tours locally. For information about how to get to UBC after arriving in the city by air, by automobile or by ferryboat contact the UBC Conference Centre web site http://www.conferences.ubc.ca. For extensive information about British Columbia in general and links to all regions contact http://travel.bc.ca. One of the registrants has also recommended the Vancouver site www.vancouver-bc.com./index.html for a lot of information about B&Bs. From cat-dist Wed Jun 11 11:52:20 1997 Received: by mailserv.mta.ca; id AA29879; Wed, 11 Jun 1997 11:51:57 -0300 Date: Wed, 11 Jun 1997 11:51:57 -0300 (ADT) From: categories To: categories Subject: Workshop Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: RO X-Status: Date: Tue, 10 Jun 1997 14:50:24 +0200 From: Bart Jacobs ANNOUNCEMENT, AND EARLY CALL FOR SUBMISSION: WORKSHOP ON COALGEBRAIC METHODS IN COMPUTER SCIENCE ======== == =========== ======= == ======== ======= (Lisbon, 28-29 March 1998 Satelite workshop to ETAPS'98) Organized by: Bart Jacobs, Larry Moss, Horst Reichel, Jan Rutten. Submissions: 1 January 1998: deadline for submissions 15 February 1998: notification 7 March 1998: final version Proceedings: ENTCS (Electronic Lecture Notes in Computer Science), and later a special issue of TCS. For more information and instructions for submission, see: http://www.cs.kun.nl/~bart/coalg_worksh.html. (We apologize for multiple copies.) From cat-dist Wed Jun 11 11:53:17 1997 Received: by mailserv.mta.ca; id AA29920; Wed, 11 Jun 1997 11:53:15 -0300 Date: Wed, 11 Jun 1997 11:53:15 -0300 (ADT) From: categories To: categories Subject: Announcement: paper on linear functors available Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: RO X-Status: Date: Wed, 11 Jun 1997 10:13:43 -0400 From: Robert A. G. Seely We wish to announce the availability of the following paper. Linearly distributive functors by J.R.B. Cockett R.A.G. Seely ABSTRACT This paper introduces a notion of "linear functor" between linearly distributive categories that is general enough to account for common structure in linear logic, such as the exponentials (!, ?), and the additives (product, coproduct), and yet when interpreted in the doctrine of *-autonomous categories, gives the familiar notion of monoidal functor. We show that there is a bi-adjunction between the 2--categories of linearly distributive categories and linear functors, and of *-autonomous categories and monoidal functors, given by the construction of the "nucleus" of a linearly distributive category. We develop a calculus of proof nets for linear functors, and show how linearity accounts for the essential structure of the exponentials and the additives. This paper was first presented at a conference held in Montreal in May 1997, in honour of Michael Barr's 60th birthday, and is dedicated to him in celebration of this occasion. ------------------------ The paper may be found at the following URLs or from the WWW home page Contact if there is any problem retrieving this paper. From cat-dist Tue Jun 17 08:34:19 1997 Received: by mailserv.mta.ca; id AA26155; Tue, 17 Jun 1997 08:32:35 -0300 Date: Tue, 17 Jun 1997 08:32:35 -0300 (ADT) From: categories To: categories Subject: pushouts in toposes Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: O X-Status: Date: Mon, 16 Jun 1997 14:22:42 +0000 From: Cesc Rossello Dear categorists A PhD student of mine, Merce Llabres, and I we have got involved in proving some properties of pushouts on toposes, similar (but somehow dual) to those known for pullbacks. We are worried by the fact that perhaps somebody else has already proved many of the results we are interested in. So, before struggling to prove some probably well-known things, we would really appreciate some pointers to literature on the topic. For instance: Assume you have a family of pushouts in a topos Ai ---> Bi | | v f v A------> B (all squares have the same bottom arrow f) with vertical arrows monic, and assume the pullbacks of (Ai -->A)_i and (Bi---> B)_i exist, say A0 and B0, and consider the obvious square A0 ---> B0 | | v f v A------> B It is a pushout square when the family of squares is finite, and for arbitrary families in all complete toposes we have tried (sets, hypergraphs, total unary algebras, unary partial algebras with closed homomorphisms,...). Moreover, a proof (for complete toposes) can probably be derived from the techniques in the paper by Kawahara in TCS vol 77 (1990). But, has somebody already proved (or disproved) such a result? Thanks in advance Cesc Rossello From cat-dist Tue Jun 17 23:51:51 1997 Received: by mailserv.mta.ca; id AA26346; Tue, 17 Jun 1997 23:51:29 -0300 Date: Tue, 17 Jun 1997 23:51:29 -0300 (ADT) From: categories To: categories Subject: Re: pushouts in toposes Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: RO X-Status: Date: Tue, 17 Jun 1997 10:32:21 -0400 (EDT) From: Peter Freyd Cesc Rossello asks about pushouts in topoi. In particular, assume that for each i, Ai ---> Bi | | A ---> B f is a pushout (same f each i) and that the vertical maps are monic (henceforth to be treated notationally as inclusion maps). Let A0 be the intersection of the Ai's and B0 the intersection of the Bi's. Then is it the case that A0 ---> B0 | | A ---> B is also a pushout? Yes for finite families, no for arbitrary families. The case for finite families is an straightforward consequence of the representation theorem for pre-topoi and the fact that such representations preserve pushouts of monics. (See 1.636 and 1.65 in Categories, Allegories.) For the failure in the infinite-family case specialize to the case that f:A --> B is also an inclusion map. The result, if true, would translate to: A v /\Bi = /\(A v Bi). Take sheaves on any non-discrete T1-space, X, for a counterexample. Let B be the terminal sheaf (i.e. X itself), A the complement of some non-isolated point and {Bi} the family of all other complements of one-element sets. From cat-dist Tue Jun 17 23:52:48 1997 Received: by mailserv.mta.ca; id AA25889; Tue, 17 Jun 1997 23:52:46 -0300 Date: Tue, 17 Jun 1997 23:52:46 -0300 (ADT) From: categories To: categories Subject: Re: pushouts in toposes Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: RO X-Status: Date: Tue, 17 Jun 1997 11:54:07 -0400 (EDT) From: Peter Freyd The distributivity condition is not only necessary and but a sufficient condition for the pushout result. A square A'--> B' | | A --> B f in which the vertical arrows are monic is a pushout iff the following three conditions hold: 1) the square is a pullback; 2) B is the union of Image(f) and B'; 3) the congruence, E, induced by f is the union of the identity relation and E ^ (A' x A'). Hence, the desired result reduces to: B = Image(f) v /\Bi; E = I v /\(E ^ (Ai x Ai)) = I v (E ^ /\(Ai x Ai)). From cat-dist Fri Jun 27 00:14:53 1997 Received: by mailserv.mta.ca; id AA24475; Fri, 27 Jun 1997 00:14:14 -0300 Date: Fri, 27 Jun 1997 00:14:14 -0300 (ADT) From: categories To: categories Subject: CT97 Lists Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: RO X-Status: Date: Thu, 19 Jun 97 15:53:45 -0700 From: John MacDonald INTERNATIONAL CATEGORY THEORY MEETING (CT97) July 13-19, 1997 University of British Columbia Vancouver, Canada The conference arrival day is Sunday July 13 with a reception 6-9pm in the Fireplace Lounge of Walter Gage Towers on the UBC campus. The scientific program will begin Monday morning July 14 at 9am in Angus 104 and will finish on Saturday July 19 at the end of the morning session (12:30pm). In order to obtain registration and housing forms send email to johnm@math.ubc.ca with the subject heading Registration. Please advise the same address of any names that should be added to or removed from any of the following lists or of any other suggestions for changes or corrections. SPEAKERS LIST M. Barr, McGill University R. Betti, Politechnico Milano, Italy D. Bourn, Universite' du Littoral, France R. Cockett, University of Calgary R. Dawson, St. Mary's University, Halifax R. Ferguson, University of British Columbia P. Freyd, University of Pennsylvania, USA J. Funk, McGill University S. Fusco, York University M. Grandis, Universita' di Genova, Italy C. Hermida, McGill University M. Hebert, American University of Cairo, Egypt H. Hu, University of Pennsylvania, USA M. Johnson, Macquarie University, Australia P. Johnstone, Cambridge University, UK M. Kelly, University of Sydney, Australia H. Kleisli, Universite' de Fribourg, Switzerland A. Kock, University of Aarhus, Denmark J. Koslowski, TU Braunschweig, Germany S. Lack, University of Sydney, Australia F. W. Lawvere, SUNY at Buffalo, USA F. Linton, Wesleyan University, USA J. MacDonald, University of British Columbia S. Mac Lane, University of Chicago, USA A. Madanshekaf, Tarbiat Modares Univ., Iran, H. Miyoshi, Shukutoku Univ., Japan S. Niefield, Union College, NY, USA J. Otto, Illinois, USA R. Pare', Dalhousie University C. Pedicchio, Universita' di Trieste, Italy J. Picado, Univ. de Coimbra, Portugal T. Plewe, Imperial College, London, UK D. Pronk, Dalhousie University L. Roman, UNAM, Mexico R. Rosebrugh, Mt. Alison University J. Rosicky, Masaryk Univ., Cech Republic G. Rosolini, Universita' di Genova, Italy A. Schauerte, University of Capetown, South Africa R. Seely, McGill University L. Sousa, Instituto Politecnico de Viseau, Portugal A. Stone, Vancouver, B.C. R. Street, Macquarie University, Australia W. Tholen, York University J. Velebil, Czech Technical University, Czech Republic J. Walters-Wayland, University of Denver, USA ADDITIONAL CONFIRMED REGISTRANTS D. Benson, Washington State University, USA D. Hofmann, Univ. Bremen, Germany W. Hunsaker, Southern Illinois Univ., USA J. Isbell, SUNY at Buffalo, USA J.W. Pelletier, York University, Canada G. Richter, Univ. Bielefeld, Germany D. Schumacher, Acadia University, Canada PREREGISTRANTS(registration not yet confirmed, as of June 19) L. Barbosa, Univ. do Minho, Portugal W. Boshuck, McGill University, Canada P.C. Carrasco, Univ. de Granada, Spain Y. Chen, Washington State Univ., USA S. Crans, Macquarie University, Australia J. Duskin, SUNY at Buffalo, USA T. Fox, McGill University, Canada F. Gago, Univ. de Santiago de Compostela, Spain P. Glenn, Catholic University of America, USA M.J. Healy, Boeing, Seattle, USA V. Huber-Dyson, Pender Island, Canada C.B. Jay, Univ. of Technology, Australia Y. Katsov, Hannover College, USA R. Kieboom, Vrije Univ. Brussel, Belgium T. Krantz, Inst. de Math. de Luminy, Marseille, France F.G. Lasteria, Politecnico di Milano, Italy H. Lord, Univ. Pomona, USA P. Mccrudden, Macquarie University, Australia S. Mantovani, Universita' di Milano, Italy F. Marmolejo, UNAM, Mexico L. Mauri, Rutgers University, USA I. Moerdijk, Univ of Utrecht, The Netherlands U. Montanari, Universita' di Pisa P. Mulry, Colgate University, USA D. Novick, Aloha, OR, USA Z. Omiadze, Acad. Sci. Georgia, Republic of Georgia F. Piessens, University of Kuleuven, Belgium H.E. Porst, Univ. of Bremen, Germany V. Pratt, Stanford University, USA L. Santocanale, UQAM, Canada P. Taylor, Imperial College, London, UK M. Thiebaud, College de Stael, Switzerland J. Thiessen, Itzehoe, Germany D. Van Osdol, University of New Hampshire, USA Y.P. Velinov, University of Natal, South Africa R.J. Wood, Dalhousie University, Canada F. Zalamea, Univ. Nacional de Columbia, Columbia The organizers of CT97 would like to acknowledge technical assistance received both from the UBC Conference Centre and the Pacific Institute for Mathematical Sciences(PIMS). From cat-dist Fri Jun 27 00:15:21 1997 Received: by mailserv.mta.ca; id AA23444; Fri, 27 Jun 1997 00:15:20 -0300 Date: Fri, 27 Jun 1997 00:15:20 -0300 (ADT) From: categories To: categories Subject: Tentative shcedule, take 2 Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: O X-Status: Date: Wed, 18 Jun 1997 08:01:29 -0400 From: Michael Barr As a result of certain constraints we were not aware of, we have had to revise the timetable for the Billfest. ALL WHO ARE SPEAKING should be aware that an abstract and title MUST BE RECEVIED BY JUN 26 if they are to be listed in the program schedule. A one sentence abstract will suffice for the abstract, if necessary. \documentstyle[12pt]{article} \textwidth 6.3in \oddsidemargin -.1in \begin{document} \begin{tabular}{|r@{--}r|l|p{3.4in}|}\hline \multicolumn4{|c|}{Friday, September 26\vrule height 15pt depth 5pt width 0pt}\\ \hline \multicolumn2{|c|}{} && \\[-10pt]\hline 8:45 & 9:30 &Andr\'e Joyal & TBA \\ \hline 9:40 & 10:10 &Marta Bunge &Functions vs Distributions\\ \hline 10:20 & 10:50 &Jonathon Funk &Complete Spreads in Topos Theory\\ \hline \multicolumn2{|c|}{} && \\[-12pt]\hline 2:30 & 3:15 &Pierre Cartier & TBA \\ \hline 3:25 & 3:55 &Phil Mulry & TBA \\ \hline 4:05 & 4:35 &Jim Otto & From NNO to Complexity \\ \hline 4:45 & 5:15 &Robert Par\'e & TBA \\ \hline \multicolumn4{|c|}{Saturday, September 27\vrule height 15pt depth 5pt width 0pt}\\ \hline \multicolumn2{|c|}{} && \\[-10pt]\hline 8:45 & 9:30 &Bill Lawvere & Toposes of Laws of Motion\\ \hline 9:40 & 10:10 &Walter Noll & TBA \\ \hline 10:20 & 10:50 &Anders Kock & TBA \\ \hline \multicolumn2{|c|}{} && \\[-12pt]\hline 2:30 & 3:15 &Peter Gabriel & TBA \\ \hline 3:25 & 3:55 &Alex Heller & TBA \\ \hline 4:05 & 4:35 &Kimmo Rosenthal& Multirelations and power quantales \\ \hline 4:45 & 5:15 &Fred Linton& Triples vs. Theories---one last time\\ \hline \multicolumn4{|c|}{Sunday, September 28\vrule height 15pt depth 5pt width 0pt}\\ \hline \multicolumn2{|c|}{} && \\[-10pt]\hline 8:45 & 9:30 &Mikhail Kapranov & TBA \\ \hline 9:40 & 10:10 &Ross Street & The Petit Topos of Globular Sets\\ \hline 10:20 & 10:50 &Todd Trimble & TBA \\ \hline \multicolumn2{|c|}{} && \\[-12pt]\hline 2:30 & 3:15 &Steve Schanuel & TBA \\ \hline 3:25 & 3:55 &Aurelio Carboni & TBA \\ \hline 4:05 & 4:35 &Jim Lambek &What is the category of sets---A tribute to Bill Lawvere \\ \hline \end{tabular} \end{document} |=======================================================================| | Friday, September 26 | |=======================================================================| |=======================================================================| | 8:45- 9:30| Andr\'e Joyal | TBA | |------------|---------------------|------------------------------------| | 9:40-10:10| Marta Bunge | Functions vs Distributions | |------------|---------------------|------------------------------------| | 10:20-10:50| Jonathon Funk | Complete Spreads in Topos Theory | |============|=====================|====================================| | 2:30- 3:15| Pierre Cartier | TBA | |------------|---------------------|------------------------------------| | 3:25- 3:55| Phil Mulry | TBA | |------------|---------------------|------------------------------------| | 4:05- 4:35| Jim Otto | From NNO to Complexity | |------------|---------------------|------------------------------------| | 4:45- 5:15| Robert Par\'e | TBA | |=======================================================================| | | | | |=======================================================================| | Saturday, September 27 | |=======================================================================| |=======================================================================| | 8:45- 9:30| Bill Lawvere | Toposes of Laws of Motion | |------------|---------------------|------------------------------------| | 9:40-10:10| Walter Noll | TBA | |------------|---------------------|------------------------------------| | 10:20-10:50| Anders Kock | TBA | |============|=====================|====================================| | 2:30- 3:15| Peter Gabriel | TBA | |------------|---------------------|------------------------------------| | 3:25- 3:55| Alex Heller | Multirelations and power quantales | |------------|---------------------|------------------------------------| | 4:05- 4:35| Kimmo Rosenthal | TBA | |------------|---------------------|------------------------------------| | 4:45- 5:15| Fred Linton |Triples vs. Theories--one last time | |=======================================================================| | | | | |=======================================================================| | Sunday, September 28 | |=======================================================================| |=======================================================================| | 8:45- 9:30| Mikhail Kapranov | TBA | |------------|---------------------|------------------------------------| | 9:40-10:10| Ross Street | The Petit Topos of Globular Sets | |------------|---------------------|------------------------------------| | 10:20-10:50| Todd Trimble | TBA | |============|=====================|====================================| | 2:30- 3:15| Steve Schanuel | TBA | |------------|---------------------|------------------------------------| | 3:25- 3:55| Aurelio Carboni | TBA | |------------|---------------------|------------------------------------| | 4:05- 4:35| Jim Lambek | What is the category of sets-- | | | | A tribute to Bill Lawvere | |=======================================================================| From cat-dist Fri Jun 27 00:16:23 1997 Received: by mailserv.mta.ca; id AA25935; Fri, 27 Jun 1997 00:16:22 -0300 Date: Fri, 27 Jun 1997 00:16:22 -0300 (ADT) From: categories To: categories Subject: CTCS'97 - support for participants Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: O X-Status: Date: Thu, 19 Jun 1997 12:06:18 +0200 From: Eugenio Moggi [Please look at the conference URL for more detailed information] CATEGORY THEORY AND COMPUTER SCIENCE (CTCS'97) 4-6 SEPTEMBER 1997, S. MARGHERITA LIGURE (GENOA), ITALY CONFERENCE URL: "http://www.disi.unige.it/conferences/ctcs97/ FINANCIAL SUPPORT FOR PARTICIPANTS Thanks to additional funding from sponsors it is possible to provide accommodation in twin bedrooms for a limited number of participants. Preference will be given to PhD students and participants from abroad. To apply for support one should send an EMAIL REQUEST to ctcs97@disi.unige.it BY JULY 10. Notification of acceptance/rejection of requests will be sent by e-mail BEFORE JULY 15. Please look at the conference URL for full details. Eugenio Moggi ************************ IMPORTANT DEADLINES ************************ **** 15 JULY 1997 early registration **** **** 31 JULY 1997 "guaranteed" hotel reservation **** ********************************************************************* From cat-dist Fri Jun 27 00:17:49 1997 Received: by mailserv.mta.ca; id AA24923; Fri, 27 Jun 1997 00:17:47 -0300 Date: Fri, 27 Jun 1997 00:17:47 -0300 (ADT) From: categories To: categories Subject: CSL'97: Programme and Call for Participation Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: O X-Status: Date: Fri, 20 Jun 1997 23:57:44 +0200 (MET DST) From: Uffe Henrik Engberg -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Programme and Call for Participation CSL'97 The 1997 Annual Conference on Computer Science Logic Aarhus, Denmark, 25-29 August, 1997 Organized by BRICS, Department of Computer Science, University of Aarhus Sponsored by BRICS, the Danish National Research Foundation and the Danish National Research Council -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- The 1997 Annual Conference on Computer Science Logic, CSL'97, will be held at the Computer Science Department, University of Aarhus, Denmark, 25 - 29 August, 1997, preceded by Tutorials, 23 - 24 August, 1997. The conference includes invited talks by the following speakers: - Samuel R. Buss, San Diego - Hubert Comon, Paris - Thierry Coquand, Gothenburg - Martin Hyland, Cambridge - Neil Immerman, Amherst - Nils Klarlund, Murray Hill - Yiannis N. Moschovakis, Los Angeles - Leszek Pacholski, Wroclaw The tutorials include a three series of lectures on the theme of Games in Computer Science Logic. The tutorials speakers are: - Samson Abramsky, Edinburgh - E. Allen Emerson, Austin - Wolfgang Thomas, Kiel - Igor Walukiewicz, Warsaw Preliminary proceedings will be available at the conference, and final proceedings will be published in Springer Lecture Notes in Computer Science, Springer Verlag. Participants will receive copies of both. Besides the scientific program, the conference offers a nice social programme including a conference dinner and an excursion visiting the Museum of Prehistory at Moesgaard and the Old Town of Aarhus. Amongst the attractions of Moesgaard are its collections from the Viking Age, and the Grauballe man, one of the only complete preserved bog bodies from the Iron age. A limited number of student grants covering accommodation, conference fee including refreshments, lunches, excursion, conference dinner and conference material, are available. Information on registering, student grants, travel etc., can be found after the conference and tutorials programme below or by visiting: http://www.brics.dk/CSL97 =========================================================================== CSL'97 Conference Programme =========================================================================== MONDAY, AUGUST 25 08:00-09:15 Registration 09:15-09:30 Welcome 09:30-10:30 Neil Immerman (invited speaker): Descriptive Complexity and Model Checking 10:30-11:00 Break 11:00-11:30 L. Staiger: Disjunctive omega-Words and Monadic Second-Order Arithmetic 11:30-12:00 D. Pardo, A. Rabinovich, B.A. Trakhtenbrot: On Synchronous Circuits over Continuous Time 12:00-12:30 A. Arnold, D. Janin: A Note on the Satisfiability Problem in Fixpoint Calculi 12:30-14:00 Lunch 14:00-15:00 Samuel R. Buss (invited speaker): Resolution, The Pigeonhole Principle and Proof Complexity 15:00-15:30 M. L. Bonet, N. Galesi: Linear Lower Bounds and Simulations in Frege Systems with Substitutions 15:30-16:00 Break 16:00-16:30 T. Coquand, H. Persson: A Proof-Theoretical Investigation of Zantema's Problem 16:30-17:00 E. Pezzoli: On the Computational Complexity of Type 2 Functionals 17:00-17:30 P. J. Voda: A Simple Ordinal Recursive Normalization of Goedel's T 17:45- EACSL Business Meeting TUESDAY, AUGUST 26 09:00-10:00 Thierry Coquand (invited speaker): Formal Topology and Inductive Definitions 10:00-10:30 M. Hollenberg: Equational Axioms of Test Algebra 10:30-11:00 Break 11:00-11:30 T. Brauener, V. de Paiva: A Dependency Formulation for Linear Logic 11:30-12:00 C. Faggian: Classical Proofs via Basic Logic 12:00-12:30 P. Baillot, V. Danos, T. Ehrhard, L. Regnier: Timeless Games 12:30-14:00 Lunch 14:00-15:00 Nils Klarlund (invited speaker): Mona & Fido: The Logic/Automaton Connection in Practice 15:00-15:30 O. Kupferman, R.P. Kurshan, M. Yannakakis: Existence of Reduction Hierarchies 15:30-16:00 Break 16:00-16:30 M. Grohe: Inversion of the L^k-invariants is Hard 16:30-17:00 A. Durand, R. Fagin, B. Loescher: Spectra with only Unary Function Symbols 17:00-17:30 F. Olive: A Conjunctive Logical Characterization of Nondeterministic Linear Time 17:30-18:00 T. Schwentick: Padding and the Expressive Power of Existential Second-Order Logics WEDNESDAY, AUGUST 27 09:00-10:00 Yiannis N. Moschovakis (invited speaker): Concurrent Recursion 10:00-10:30 R. Backofen, P. Clote: Evolution as a Computational Engine 10:30-11:00 Break 11:00-11:30 I. Schiering: A Hierarchical Approach to Graph Automata and Monadic Second-Order Logic over Graphs 11:30-12:00 N. Schweikardt: The Monadic Quantifier Alternation Hierarchy over Grids and Pictures 12:00-12:30 A. Ayari, D. Basin, A. Podelski: Lisa: A Specification Language Based on WS2S 13:30- Excursion THURSDAY, AUGUST 28 09:00-10:00 Hubert Comon (invited speaker): Higher-Order Matching and Tree Automata 10:00-10:30 F. Kamarredine, R. Bloo, R. Nederpelt: An Approximation of Reductional Equivalence 10:30-11:00 Break 11:00-11:30 A. Barber, P. Gardner, M. Hasegawa, G. Plotkin: From Action Calculi to Linear Logic 11:30-12:00 P. Ruet, F. Fages: Concurrent Constraint Programming and Mixed Non-Commutative Linear Logic 12:00-12:30 M. Hofmann: A Mixed Modal/Linear Lambda Calculus with Applications to Bellantoni-Cook Safe Recursion 12:30-14:00 Lunch 14:00-15:00 Martin Hyland (invited speaker): Constructing Categories of Abstract Games 15:00-15:30 J. Power: Categories with Algebraic Structure 15:30-16:00 Break 16:00-16:30 S. Abramsky, G. McCusker: Call-by-Value Games 16:30-17:00 R. Heckmann, M. Huth: A Duality Theory for Quantitative Semantics 17:00-17:30 T. Hartonas, M. Hennessy: Full Abstractness for a Functional/Concurrent Language with Higher-Order Value-Passing 19:00- Conference Dinner FRIDAY, AUGUST 29 09:00-10:00 Leszek Pacholski (invited speaker): Complexity of Type Inference 10:00-10:30 G. Davydov, I. Davydova: Applications of Unsatisfiability 10:30-11:00 Break 11:00-11:30 P. A. Bonatti, N. Olivetti: A Sequent Calculus for Circumscription 11:30-12:00 J. Hudelmaier: Bicomplete Calculi for Intuitionistic Propositional Logic 12:00-12:30 S. Brass, J. Dix, I. Niemelae, T. C. Przymusinski: A Comparison of the Static and the Disjunctive Well-founded Semantics 12:30-14:00 Lunch End of Conference =========================================================================== CSL'97 Tutorials Programme =========================================================================== SATURDAY, AUGUST 23 09:00-09:15 Welcome 09:15-10:45 Samson Abramsky, Univ. of Edinburgh: Game Semantics 10:45-11:15 Break 11:15-12:15 Wolfgang Thomas, Univ. of Kiel: Determinacy, the Rabin Tree Theorem and its extensions 12:15-14:00 Lunch 14:00-15:00 Wolfgang Thomas: Determinacy, the Rabin Tree Theorem and its extensions 15:00-15:30 Break 15:30-17:00 Samson Abramsky: Game Semantics SUNDAY, AUGUST 24 09:15-10:45 E. Allen Emerson, Univ. of Texas at Austin: Games, mu-calculus, and program verification 10:45-11:15 Break 11:15-12:15 Igor Walukiewicz, Univ. of Warsaw: Determinacy, the Rabin Tree Theorem and its extensions 12:15-14:00 Lunch 14:00-15:00 Igor Walukiewicz: Determinacy, the Rabin Tree Theorem and its extensions 15:00-15:30 Break 15:30-17:00 E. Allen Emerson: Games, mu-calculus, and program verification Tutorial Abstracts Samson Abramsky: Game Semantics for Programming Languages Abstract These lectures will give an introduction to game semantics and its applications to modelling programming languages. The mathematical structure of categories of games will be described, and it will be shown how they can be used to model a range of computational features in a precise way. E. Allen Emerson: Games, mu-calculus, and Program Verification Abstract Temporal logics are often used to verify concurrent programs using such techniques as model checking. We describe some intimate connections between such temporal logics, the related fixpoint logic known as the mu-calculus, and infinite games. Applications include improved nonemptiness algorithms for tree automata, mu-calculus characterizations of winning strategies in memoryless games, and an automata-theoretic characterization of the complexity of model checking in the mu-calculus. Wolfgang Thomas, Igor Walukiewicz: Determinacy, the Rabin Tree Theorem and its Extensions Abstract We present a self-contained proof of Rabin's Tree Theorem (decidability of the monadic theory of two successors). The proof uses memoryless determinacy of infinite games. We also show some extensions of the theorem to tree-like infinite graphs and discuss connections with fixed point calculi. =========================================================================== Further Information =========================================================================== How to Register ================ To get more detailed information on CSL'97, including information on registering, please visit: http://www.brics.dk/CSL97 We encourage you to register via this www page, but alternatively you may send an email to csl97@brics.dk including your surface mail address requesting a copy of the registration form to be forwarded. Notice that the deadline for early registration (DKK 2000) has been extended to July 11. Please also note that there is a reduced student registration fee (DKK 600). Registration Fees Particip. paid before July 11: DKK 2000 Particip. paid after July 11: DKK 2500 Student registration: DKK 600 Tutorials, paid before July 11: DKK 300 Tutorials, paid after July 11: DKK 400 The registration fees cover refreshments, lunches, excursion, banquet and conference material. See registration form for payment. If payment is made by credit card, the registration form must be signed and mailed or faxed to the Convention Bureau. All correspondence concerning registration and accommodation (payment, reservation, cancellation, etc.) should be sent to CSL'97 Aarhus Convention Bureau Raadhuset DK-8000 Aarhus C Denmark Telephone: +45 8612 1177 Telefax: +45 8612 0807 e-mail: aarhconv@inet.uni-c.dk Please give phone and/or telefax numbers on all inquiries to the Convention Bureau. Accompanying Persons ================== Please register accompanying persons on the registration form. Tickets for lunches, excursion and conference dinner may be purchased at the registra- tion desk. Grants ================== A limited number of student grants to attend the Conference and/or the Tutorials are available. The grants will cover local expenses (accom- modation at the nearby Youth Hostel and conference fee, including lunches and coffees during the conference, excursion and conference dinner). They will not cover travel expenses. The deadline for application is July 1, 1997. To apply, you fill out an application form available from the above mentioned www page, and return it with a short description of your research activity and a letter of recommendation from your supervisor or from the head of the department to Prof. Mogens Nielsen, CSL'97 Department of Computer Science University of Aarhus Ny Munkegade, Building 540 DK-8000 Aarhus C Denmark Inquiries ================== Organisational inquiries about the conference can be sent to: CSL97@brics.dk Local Organization ================== BRICS, Department of Computer Science University of Aarhus Ny Munkegade DK-8000 Aarhus C Denmark Telephone: +45 8942 3360 Telefax: +45 8942 3255 e-mail: csl97@brics.dk http://www.brics.dk/CSL97 Organizing Committee ================== Mogens Nielsen (chair) Gian Luca Cattani Uffe Engberg Karen K. Moeller Program Committee ================== K. Compton (Ann Arbor) J. Flum (Freiburg) F. Honsell (Udine) J. W. Klop (Amsterdam) V. W. Marek (Lexington) M. Nielsen (Aarhus, Vice-chair) P. Pudlak (Prague) E. Robinson (QMW, London) A. Tarlecki (Warsaw), W. Thomas (Kiel, Chair), I. Walukiewicz (Warsaw). Travel information ================== By air Aarhus Airport/Tirstrup is connected with Copenhagen International Airport through 19 daily departures on weekdays, 7-8 departures on Saturdays and Sundays. Flying time is 35 minutes. Aarhus Airport, located 40 km north of the city, offers direct international flights to Oslo, Stockholm, Gothenburg, London Heathrow and Amsterdam. Billund Airport, located 100 km south of Aarhus, has direct international flight connections to Amsterdam, Brussels, Paris, Nice, Frankfurt, London, Birmingham, Manchester, Riga, Oslo, Bergen, Stavanger, Stockholm and Berlin. By train/car From Southern and Central Europe, the train/car connections are via Hamburg/-Flensburg. Travel time from Hamburg to Aarhus is approximately five hours. >From Eastern European countries train connections to Aarhus go via Poland and Copenhagen. Aarhus has an hourly service to and from Copenhagen and several daily connections to Sweden, Germany and the rest of Europe. Travel time Copenhagen-Aarhus is 3 hrs. 15 min. Accommodation ============= Aarhus Convention Bureau has made preliminary hotel reservations for the CSL'97 participants. Please use the registration form to book rooms. The hotels have been divided into three categories according to standard or comfort. The organizers cannot guarantee accommodation to participants who do not book in advance. Payment has to be made directly to the hotel upon departure. Social Program ============== Get-together: Get-together parties will be held on Friday, August 22 and Sunday, August 24, 7:00-10:00 pm at the conference venue. Beer and soft drinks will be served. Excursion: Wednesday, August 27, 1997 Programme 13:30 Departure from the conference site to the Museum of Prehistory at Moesgaard, a culture-historical museum which specializes in prehistoric archaeology and ethnography. The collections are from the Danish prehistory ranging from the Paleolithic Age to the end of the Viking Age. One of the major attractions is the Grauballe man - the only completely preserved bog body from the Iron Age (1st century BC). An ethnographical special exhibition about mountain people of the Hindu Kush is also on show at Moesgaard. On the museum grounds a replica of a stave church from the Viking Age is being erected this summer. The building is 9.5 m long and almost 5 m wide and is a reconstruction of a church found during excavation in Hoerning Church near Randers. The church is built to the north of the Hedeby house just behind the museum. Not since the Viking Age has a stave church been built in Denmark. The public is invited to follow the reconstruction. Weather permitting, we will take a prehistoric walk through fields and woods passing reconstructions of Iron Age houses, places of cult, and dolmens from the Stone Age. Refreshments will be served on the beach. 16:00 Buses will return to the centre of Aarhus, more precisely to The Old Town, an open-air museum with more than 75 half-timbered houses, rebuilt along cobbled streets and fitted out with all the workshops and furnishings of a Danish market town, reflecting life from 1600 down to our grand- parents' time. A meal in the Old Town restaurant, Simonsen's Garden, will finish the excursion. Conference Dinner: The conference dinner will be held on the evening of Thursday, August 28, starting at 7 pm in the canteen at the conference venue. From cat-dist Fri Jun 27 00:20:38 1997 Received: by mailserv.mta.ca; id AA26046; Fri, 27 Jun 1997 00:20:37 -0300 Date: Fri, 27 Jun 1997 00:20:37 -0300 (ADT) From: categories To: categories Subject: REMINDER: MATHFIT Summer School and Workshop Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: O X-Status: Date: Thu, 26 Jun 97 10:30:06 BST From: M.Z.Kwiatkowska@cs.bham.ac.uk Dear Colleagues, We enclose a reminder of two events to be held in Birmingham this September. Please note that the deadline for early registration and applications for grants is ***30th June***. Please forward to anyone interested. Best wishes, Achim and Marta. ------------------------------------------------------------------------- SUMMER SCHOOL and WORKSHOP on NEW PARADIGMS FOR COMPUTATION ON CLASSICAL SPACES Birmingham, 8-10 September 1997 and 11-13 September 1997 The two events are centered around recent developments in the theory of continuous domains as applied to classical problems in Mathematics and Semantics. These developments are based on ground-breaking work by Abbas Edalat who, using earlier work by Jimmie Lawson, Claire Jones and Gordon Plotkin, showed in the early 90's how a classical (locally compact) space could be embedded as the set of maximal points in a domain. This led to a new theory of integration with applications in the theory of Iterated Function Systems, Neural Networks, Statistical Physics, and Fractal Geometry. More recently, Abbas Edalat and Martin Escardo have made substantial progress on the question of exact real number computation. The Summer School is intended to teach the mathematical background of the theory enabling participants to fully take part in the following Workshop. A small number of grants for the Summer School are available for PhD students. Further information can be found at http://www.cs.bham.ac.uk/~axj/comprox.html From cat-dist Sun Jun 29 11:37:13 1997 Received: by mailserv.mta.ca; id AA26707; Sun, 29 Jun 1997 11:36:43 -0300 Date: Sun, 29 Jun 1997 11:36:43 -0300 (ADT) From: categories To: categories Subject: Re: pushouts in toposes Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: RO X-Status: Date: Sun, 22 Jun 1997 11:54:47 -0300 From: RJ Wood A belated, somewhat tangential comment, on the distributivity condition A v /\Bi = /\(A v Bi) that Peter mentioned in his posts. The subobject classifier, Omega, satisfies this condition (internally) if and only if the topos is boolean. See the proof of Theorem 10 in Constructive Complete Distributivity II, Math Proc Cam Phil Soc, (1991) 110, 245-249, by Rosebrugh and Wood, which shows that if Omega^op is Heyting then Omega is Boolean. This result was discovered independently by Richard Squire in his thesis. It has always struck me as somewhat surprising but in the Rosebrugh/ Wood proof it is an immediate consequence of the corollary of the following result which I believe is due to Benabou and which seems to be not well known: LEMMA If f <= id:Omega--->Omega then f(u) = u/\f(true). COROLLARY If f <= id:Omega--->Omega and f(true) = true then f = id. (If Omega^op is Heyting, apply the corollary to --, where - is the negation for Omega^op.) RJ From cat-dist Sun Jun 29 11:37:28 1997 Received: by mailserv.mta.ca; id AA25849; Sun, 29 Jun 1997 11:37:27 -0300 Date: Sun, 29 Jun 1997 11:37:27 -0300 (ADT) From: categories To: categories Subject: algebraic logic via arrows Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: O X-Status: Date: Mon, 23 Jun 1997 17:39:12 +0000 From: Zinovy Diskin I'd be grateful for comments on the following question motivated by a problem in categorizing algebraic logic a la Tarski. Let C be a complete category with a factorization system (E,M). Given an object A\in C, let us call a pair (m,e) with m\in M, cod(m)=A and e\in E, dom(e)=A, {\it compatible}, m~e, if the square * --m--> A | | e' e | | v v *--m'--> A/e is pull-back (where (e',m') factorizes m;e ). In SET with the standard surjection-injection factorization, m~e iff for all a,b\in A, a\in A_m and e(a)=e(b) entail b\in A_m where A_m is the subset of A corresponding to m. Now let (e_i, i\in I) be a family of congruences compatible with some m:*--->A, e_i ~ m for all i\in I. The question is what properties of (C,E,M) are required to provide sup(e_i, i\in I) ~ m ? (the collection CongA of e:A-->*, e\in E is a meet-complete semilattice due to products, sup is join-via-meets in this lattice). If C is a category of finitary algebras over SET with the standard epi-mono factorization, then sup(e_i) ~ m always holds due to the finitary deduction property of taking sup in the congruence lattice: (a,b)\in sup(e_i) iff there exists a finite subfamily e_1,...,e_k and c_0,...,c_k \in A s.t. a=c_0, b=c_k and e_j(c_{j-1}) =e_j(c_j) for all j=1,...,k . Zinovy Diskin From cat-dist Sun Jun 29 11:39:22 1997 Received: by mailserv.mta.ca; id AA06160; Sun, 29 Jun 1997 11:39:21 -0300 Date: Sun, 29 Jun 1997 11:39:21 -0300 (ADT) From: categories To: categories Subject: Query Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: O X-Status: ---------- Forwarded message ---------- Date: Thu, 26 Jun 1997 13:57:18 +0300 (IDT) From: ZIPPIE Gonczarowski To: cat-dist@mta.ca Dear Colleagues, I am applying tools of category theory to research in artificial perception and cognition. A basic category is proposed where every perception is an object and morphisms capture the flow between perceptions. Natural transformations capture paths to more cognitive perceptions. An Anonymous referee remarked that my category is `very closely related to comma categories'. Can anybody refer me to written material that introduces comma categories? Also, please let me know if you are aware of other research that applies categorical tools to research in artificial perception and cognition. Thanks Zippie e-mail zippie@actcom.co.il Dr. Zippora Arzi-Gonczarowski Typographics, Ltd. 46 Hehalutz St. Jerusalem 96222, Israel From cat-dist Mon Jun 30 23:37:09 1997 Received: by mailserv.mta.ca; id AA24507; Mon, 30 Jun 1997 23:36:23 -0300 Date: Mon, 30 Jun 1997 23:36:23 -0300 (ADT) From: categories To: categories Subject: PSSL65 - Preliminary Announcement Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: RO X-Status: Date: Fri, 27 Jun 1997 16:23:11 +0200 (MET DST) From: Carsten Butz --------------------------------------------------------------------------- Preliminary announcement: 65th Peripatetic Seminar on Sheaves and Logic (PSSL) Dear colleagues, The next Peripatetic Seminar on Sheaves and Logic will be held in Aarhus (Denmark) over the weekend of 1-2 November 1997. We welcome talks on category theory, sheaves, logic, and related areas. The first announcement, including information about accommodation and how to get to Aarhus, will be sent out later during the summer on this category mailing list. We will maintain as well a WWW-page including (hopefully) relevant information for the seminar, although this is only in addition to the standard procedures. The URL is http://www.brics.dk/~butz/PSSL65/pssl65.html Also, we would like to mention that Birmingham has plans to organise the next PSSL (spring 1998) (contacts Neil Ghani, Neil.Ghani@cs.bham.ac.uk or Valeria DePaiva, V.DePaiva@cs.bham.ac.uk). Another one will probably take place in Utrecht in May 1998 (contact Ieke Moerdijk, moerdijk@math.ruu.nl). Best regards, Carsten Butz and Anders Kock ------------------------------------------ Carsten Butz BRICS Department of Computer Science University of Aarhus Ny Munkegade, building 540 8000 Erhus C Denmark butz@brics.dk http://www.brics.dk/~butz ------------------------------------------ From cat-dist Mon Jun 30 23:37:15 1997 Received: by mailserv.mta.ca; id AA01214; Mon, 30 Jun 1997 23:37:04 -0300 Date: Mon, 30 Jun 1997 23:37:04 -0300 (ADT) From: categories To: categories Subject: Timetable for Billfest Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: RO X-Status: Date: Sat, 28 Jun 1997 11:41:49 -0400 From: Michael Barr Below (in latex, followed by ascii) is what is hopefully the final schedule for the Billfest. Amazingly, every speaker got a title and abstract to the AMS by the 26th. I should also mention that Beno Eckmann will be in Montreal from Sept 21-28. He will talk in the category seminar on Sept. 23 and we are trying to arrange a colloquium for Sept. 25. Michael \documentstyle[12pt]{article} \textwidth 6.3in \oddsidemargin -.1in \pagestyle{empty} \begin{document} \begin{tabular}{|r@{--}r|l|p{3.4in}|}\hline \multicolumn4{|c|}{Friday, September 26\vrule height 15pt depth 5pt width 0pt}\\ \hline \multicolumn2{|c|}{} && \\[-10pt]\hline 8:45 & 9:30 &Andr\'e Joyal & The theory of $h$-categories \\ \hline 9:40 & 10:10 &Marta Bunge &Functions vs Distributions on Grothendieck toposes\\ \hline 10:20 & 10:50 &Jonathon Funk &Complete Spreads in Topos Theory\\ \hline \multicolumn2{|c|}{} && \\[-12pt]\hline 2:30 & 3:15 &Pierre Cartier & Computation and visualization: a new philosophy of categories \\ \hline 3:25 & 3:55 &Phil Mulry & Remarks on Categorical Fixed Points \\ \hline 4:05 & 4:35 &Jim Otto & From NNO to Complexity \\ \hline 4:45 & 5:15 &Robert Par\'e & On the Cardinality of Functors \\ \hline \multicolumn4{|c|}{Saturday, September 27\vrule height 15pt depth 5pt width 0pt}\\ \hline \multicolumn2{|c|}{} && \\[-10pt]\hline 8:45 & 9:30 &Bill Lawvere & Toposes of Laws of Motion\\ \hline 9:40 & 10:10 &Walter Noll &Conceptual Mathematics, Categories, Functors, and Tensors \\ \hline 10:20 & 10:50 &Anders Kock & Geometric Construction of the Levi-Civita Parallelism \\ \hline \multicolumn2{|c|}{} && \\[-12pt]\hline 2:30 & 3:15 &Peter Gabriel & Categories and Representation Theory\\ \hline 3:25 & 3:55 &Alex Heller & Semistabilization and infinite loop-spaces \\ \hline 4:05 & 4:35 &Kimmo Rosenthal& Multirelations and power quantales \\ \hline 4:45 & 5:15 &Fred Linton& Triples vs. Theories---one last time\\ \hline \multicolumn4{|c|}{Sunday, September 28\vrule height 15pt depth 5pt width 0pt}\\ \hline \multicolumn2{|c|}{} && \\[-10pt]\hline 8:45 & 9:30 &Mikhail Kapranov & Dg-thickenings of classifying spaces \\ \hline 9:40 & 10:10 &Ross Street & The Petit Topos of Globular Sets\\ \hline 10:20 & 10:50 &Todd Trimble & Opetopes and bar constructions \\ \hline \multicolumn2{|c|}{} && \\[-12pt]\hline 2:30 & 3:15 &Steve Schanuel & Objective number theory \\ \hline 3:25 & 3:55 &Aurelio Carboni & Syntactic characterizations of various classes of locally presentable categories \\ \hline 4:05 & 4:35 &Jim Lambek &What is the category of sets---A tribute to Bill Lawvere \\ \hline 4:45 & 5:15 &Claudio Hermida&Higher-dimensional multicategories \\ \hline \end{tabular} \end{document} |=======================================================================| | Friday, September 26 | |=======================================================================| |=======================================================================| | 8:45- 9:30| Andr\'e Joyal | The theory of h-categories | |------------|---------------------|------------------------------------| | 9:40-10:10| Marta Bunge | Functions vs Distributions | | | | on Grothendieck toposes | |------------|---------------------|------------------------------------| | 10:20-10:50| Jonathon Funk | Complete Spreads in Topos Theory | |============|=====================|====================================| | 2:30- 3:15| Pierre Cartier | Computation and visualization: | | | | a new philosophy of categories | |------------|---------------------|------------------------------------| | 3:25- 3:55| Phil Mulry | Remarks on Categorical Fixed Points| |------------|---------------------|------------------------------------| | 4:05- 4:35| Jim Otto | From NNO to Complexity | |------------|---------------------|------------------------------------| | 4:45- 5:15| Robert Par\'e | On the Cardinality of Functors | |=======================================================================| | | | | |=======================================================================| | Saturday, September 27 | |=======================================================================| |=======================================================================| | 8:45- 9:30| Bill Lawvere | Toposes of Laws of Motion | |------------|---------------------|------------------------------------| | 9:40-10:10| Walter Noll | Conceptual Mathematics, Categories,| | | | Functors, and Tensors | |------------|---------------------|------------------------------------| | 10:20-10:50| Anders Kock | Geometric Construction of | | | | the Levi-Civita Parallelism | |============|=====================|====================================| | 2:30- 3:15| Peter Gabriel |Categories and Representation Theory| |------------|---------------------|------------------------------------| | 3:25- 3:55| Alex Heller | Semistabilization and | | | | infinite loop-spaces | |------------|---------------------|------------------------------------| | 4:05- 4:35| Kimmo Rosenthal | Multirelations and power quantales | |------------|---------------------|------------------------------------| | 4:45- 5:15| Fred Linton |Triples vs. Theories--one last time | |=======================================================================| | | | | |=======================================================================| | Sunday, September 28 | |=======================================================================| |=======================================================================| | 8:45- 9:30| Mikhail Kapranov |Dg-thickenings of classifying spaces| |------------|---------------------|------------------------------------| | 9:40-10:10| Ross Street | The Petit Topos of Globular Sets | |------------|---------------------|------------------------------------| | 10:20-10:50| Todd Trimble | Opetopes and bar constructions | |============|=====================|====================================| | 2:30- 3:15| Steve Schanuel | Objective number theory | |------------|---------------------|------------------------------------| | 3:25- 3:55| Aurelio Carboni | Syntactic characterizations of | | | | various classes of locally | | | | presentable categories | |------------|---------------------|------------------------------------| | 4:05- 4:35| Jim Lambek | What is the category of sets-- | | | | A tribute to Bill Lawvere | |------------|---------------------|------------------------------------| | 4:45- 5:15| Claudio Hermida | Higher-dimensional multicategories | |=======================================================================| From cat-dist Mon Jun 30 23:37:56 1997 Received: by mailserv.mta.ca; id AA07277; Mon, 30 Jun 1997 23:37:55 -0300 Date: Mon, 30 Jun 1997 23:37:55 -0300 (ADT) From: categories To: categories Subject: functions Omega->Omega Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: RO X-Status: Date: Sun, 29 Jun 1997 19:04:54 +0100 (BST) From: Paul Taylor Richard Wood mentioned an observation about functions Omega->Omega in a topos. In the more abstract situation of a classifier Sigma for some subclass of monos (closed under isomorphisms, composition and pullback along arbitrary maps, and such that the characteristic function of a subobject, where it exists, is unique), the following formula holds: for any function f:Sigma x X -> X and predicate a:X -> Sigma f(a) & a = f(true) & a In fact, along with Sigma being a semilattice, this is necessary and sufficient for Sigma and its powers to form a full subcategory of some category in which Sigma is a classifier. I wonder whether anyone has noticed this formula before? In my construction, the Frobenius law for an existential quantifier is derivable from it. It is also reminiscent of the Berry order in stable domain theory, but I can see no substantial connection. It is easily provable in higher order logic: either way, assume a, so a=true. Curiously, Phoa's Principle (in synthetic domain theory) is the conjunction of the higher order equation above its lattice dual f(a) \/ a = f(false) \/ a and all functions f:Sigma->Sigma are monotone. For the continuation of this story, go to Vancouver ... Paul From cat-dist Mon Jun 30 23:39:29 1997 Received: by mailserv.mta.ca; id AA05894; Mon, 30 Jun 1997 23:39:28 -0300 Date: Mon, 30 Jun 1997 23:39:28 -0300 (ADT) From: categories To: categories Subject: Re: Query Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: O X-Status: Date: Sun, 29 Jun 1997 11:58:50 -0700 (PDT) From: Dr. Farogh Dovlatshahi This is not an answer to your question. But your posting prompts me to ask a question in the semantics underlying applications of cateogories. What is the underlying metaphysics of perception (event, processes, relations ?). How do you capture 'time'. It seems to me the dynamism is in the arrows -- and there perhaps is where time comes in. It has always seemed to me that the applications of Cat. The. (for example in the study of Dynamical Systems) has served as a language to talk about mathematical, computatianal and procedural complexities ONCE THESE ARE ALREADY IN PALCE. Cat. is not to replace them as an alternative. Dr. Farogh Dovlatshahi > > > > Dear Colleagues, > > I am applying tools of category theory to research in artificial > perception and cognition. A basic category is proposed where every > perception is an object and morphisms capture the flow between > perceptions. Natural transformations capture paths to more cognitive > perceptions. > An Anonymous referee remarked that my category is `very closely related > to comma categories'. > > Can anybody refer me to written material that introduces comma categories? > Also, please let me know if you are aware of other research that applies > categorical tools to research in artificial perception and cognition. > > Thanks > > Zippie > > e-mail zippie@actcom.co.il > > Dr. Zippora Arzi-Gonczarowski > Typographics, Ltd. > 46 Hehalutz St. > Jerusalem 96222, Israel > > From cat-dist Mon Jun 30 23:40:32 1997 Received: by mailserv.mta.ca; id AA06289; Mon, 30 Jun 1997 23:40:30 -0300 Date: Mon, 30 Jun 1997 23:40:30 -0300 (ADT) From: categories To: categories Subject: AMAST '97 - Call for TOOL AND SYSTEM DEMOS Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: O X-Status: Date: Mon, 30 Jun 1997 09:48:09 +1000 From: Richard Buckland -------------------------------------------------------------------- Call for TOOL AND SYSTEM DEMONSTRATIONS Sixth International AMAST Conference AMAST '97, December 13-17, 1997, Sydney, Australia. -------------------------------------------------------------------- We invite demonstrations of software tools and systems. Goals: TOOL and SYSTEM DEMONSTRATIONS The major goal of the AMAST Conferences is to put software development technology on a firm, mathematical foundation. An important aspect of this long term goal is to circulate information about the experience of actual developments, and to encourage the development of and dissemination of information about software tools and development support systems. Accordingly we invite submissions of demonstrations in the following two categories: 1. Tools and Engines to Support formal software development 2. Examples of systems developed using algebraic methodologies -------------------------------------------------------------------- Demonstrations 1. TOOLS AND ENGINES TO SUPPORT FORMAL SOFTWARE DEVELOPMENT An essential component of mathematically founded software development is computational support. Following the successful trend established in the 1995 and 1996 meetings AMAST'97 will include sessions to demonstrate systems with relevance to algebraic or logical methodologies of software development. These sessions have proved popular with attendees in the past as they provide an opportunity for the wide range of researchers and practitioners attending the conference to discover and to learn more about tools and computational engines to support their work. The topics of interest include, but are not limited to, the following: - Software development environments - Support for correct software development - System support for reuse - Tools for prototyping - Validation and verification - Computer algebra systems - Theorem proving systems - Engines and computational support for the above - Systems supporting the education of students and/or practitioners in relevant topics 2. EXAMPLES OF SYSTEMS DEVELOPED USING ALGEBRAIC METHODOLOGIES Topics of interest include, but are not limited to, the following: - System demonstrations showing the improved effectiveness of software developed on a mathematical basis. - Case studies. - Unsuccessful system developments. - Reports on current commercial and industrial practice. -------------------------------------------------------------------- Submissions We invite submissions of tool and system demonstrations. Prospective demonstrators should submit electronically in one or both of the following formats: 1. A paper of high quality of between two and five pages in LNCS style. Submissions in this category should be of theoretical merit and report on previously unpublished work. 2. An abstract of one to two pages providing a description of the tool or system to be demonstrated and containing pointers to further information, preferably available electronically. It is anticipated that the abstracts will be published at the rear of the proceedings in the form of a reference for practitioners, and additionally as an on-line reference on the world wide web. Please see details at http://www.cs.mq.edu.au/amast97 under "submission" which explain how to get a paper number, and then submit a fully self-contained postscript file via ftp (preferably derived from LaTeX with the LNCS style on a standard UNIX system). If for any reason it is impossible to submit electronically authors may send six paper copies of their submission to the Tools and Demos address below. All papers will be refereed and will be judged based on their significance, technical merit, and relevance to the conference. As in the past, we expect the proceedings to be published by Springer-Verlag in their Lecture Notes in Computer Science Series. Papers and abstracts should be received by July 7, 1997. -------------------------------------------------------------------- General AMAST Goals The major goal of the AMAST Conferences is to put software development technology on a firm, mathematical foundation. Particular emphasis is given to algebraic and logical foundations of software technology. An eventual goal is to establish algebraic and logical methodologies as practically viable and attractive alternatives to the prevailing approaches to software engineering. Previous meetings of AMAST were held in Iowa (1989 and 1991), Twente, Holland (1993), Montreal (1995) and Munich (1996). During these meetings, AMAST has attracted an international spread of researchers and practitioners interested in software technology, programming methodology and their algebraic and logical foundations. In addition, the first day of each conference has been dedicated to Mathematics Education for Software Engineers. The sixth AMAST International Conference will be held at Macquarie University, Sydney, Australia, from December 13 to December 17, 1997. -------------------------------------------------------------------- Further Information Address for non-electronic submissions and inquiries: Richard Buckland AMAST'97 Tools and Demos School of Computer Science and Engineering University of New South Wales Sydney, 2052, Australia Phone: ++61 (0)2 9698 7975 Fax: ++61 (0)2 9385 5995 For further information on the conference: http://www.cs.mq.edu.au/amast97 amast97@mpce.mq.edu.au -------------------------------------------------------------------- AMAST General Chair: Maurice Nivat (France) Programme Chair: Michael Johnson (Australia) -------------------------------------------------------------------- Programme Committee V.S. Alagar (Canada), Egidio Astesiano (Italy), Didier Begay (France), Richard Buckland (Australia), John Cannon (Australia), Kokichi Futatsugi (Japan), Armando Haeberer (Brazil), Paola Inverardi (Italy), Michael Johnson (Australia), Rocco De Nicola (Italy), Anton Nijholt (Netherlands), Fernando Orejas (Spain), Mehmet Orgun (Australia), John Plaice (Canada) John Potter (Microsoft Research Institute), R. Ramanujam (India), Charles Rattray (Great Britain), Teodor Rus (USA), T. Sakabe (Japan), Giuseppe Scollo (Netherlands), R.K. Shyamasundar (India), Andrzej Tarlecki (Poland), R.F.C Walters (Australia), Martin Wirsing (Germany). -------------------------------------------------------------------- Tool and System Demos Committee Richard Buckland (University of New South Wales) Ken Robinson (University of New South Wales) Jon Tidswell (Microsoft Research Institute) -------------------------------------------------------------------- Important Dates for Tool and System Demonstrations Submission of Demo Proposals: July 12, 1997 Author notification of outcome: August 12, 1997 Camera ready copy received by: September 1, 1997 Education Day: December 13, 1997 Conference Days: December 14-17, 1997 [This announcement is available on the AMAST'97 WWW site, at URL: http://www.cs.mq.edu.au/amast97/demo-cfp.html ] ---------------------------------------------------------------- Richard Buckland School of Computer Science and Engineering The University of New South Wales From cat-dist Mon Jun 30 23:41:45 1997 Received: by mailserv.mta.ca; id AA02357; Mon, 30 Jun 1997 23:41:44 -0300 Date: Mon, 30 Jun 1997 23:41:44 -0300 (ADT) From: categories To: categories Subject: Re: Query Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: O X-Status: Date: Sun, 29 Jun 1997 20:49:19 -0400 From: Michael Barr Not that I am blowing my own horn (but why not), you will find something about comma categories in Barr & Wells, Category Theory for Computing Science. But no, I know of no other research along those lines. Michael Barr From cat-dist Mon Jun 30 23:42:45 1997 Received: by mailserv.mta.ca; id AA06928; Mon, 30 Jun 1997 23:42:44 -0300 Date: Mon, 30 Jun 1997 23:42:44 -0300 (ADT) From: categories To: categories Subject: Re: algebraic logic via arrows Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Status: O X-Status: Date: Mon, 30 Jun 1997 11:07:12 +0100 From: Marco Grandis This is a collateral remark, but I would be surprised if there were no connections. In an abelian category C, a square of epis and monos as considered by Zinovy Diskin * --m--> A | | e' e | | v v X --m'--> * is a pullback iff it is a pushout. Such a bicartesian square represents a "subquotient" X of A (a subobject m' of a quotient e, and a quotient e' of a subobject m); and it is a subobject X >-+-> A in the category of relations RelC. Subquotients are a crucial tool in homological algebra, where everything - from homology to the terms of spectral sequences - is a subquotient of some "main object" (or an induced morphism between subquotients). See MacLane, "Homology". A categorical study of subquotients in abelian categories and their extensions can be found in the following papers of mine. The last setting ("semiexact" and "homological" categories) is much more general than the classical abelian one M. Grandis, Sous-quotients et relations induites dans les categories exactes, Cahiers Top. Geom. Diff. 22 (1981), 231-238. -, On distributive homological algebra, I. RE-categories; II. Theories and models; III. Homological theories. Cahiers Top. Geom. Diff. 25 (1984), 259-301; 353-379; 26 (1985), 169-213. -, On the categorical foundations of homological and homotopical algebra, Cahiers Top. Geom. Diff. Categ. 33 (1992), 135-175. With best regards Marco Grandis