From cat-dist Wed Sep 1 15:01:02 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id NAA13977 for categories-list; Wed, 1 Sep 1999 13:22:57 -0300 (ADT) X-Authentication-Warning: mailserv.mta.ca: Majordom set sender to cat-dist@mta.ca using -f Message-ID: <010601bef39f$8e06ea00$9250d383@dns.microsoft.com> Reply-To: "Erik Meijer" From: "Erik Meijer" To: Subject: categories: PhD and Postdoc Positions in Software Technology (Utrecht University) Date: Tue, 31 Aug 1999 12:57:01 +0200 Organization: Utrecht University MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.00.2314.1300 X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by mailserv.mta.ca id HAA30399 Sender: cat-dist@mta.ca Precedence: bulk Status: RO X-Status: [Apologies if you receive multiple copies of this message] PhD and POST-DOC POSITIONS AVAILABLE Department of Computer Science Utrecht University The Netherlands http://www.cs.uu.nl The Software Technology research group at Utrecht University has several doctoral and post-doctoral positions available. The positions are funded by the department, Microsoft Research, and the Dutch Science Foundation (NWO). The main research interests of the group are tool support for the development of computer assisted teaching material, components and scripting, program generation and transformation, tree displaying and manipulation, generic programming, and provably correct systems. We seek candidates in any of the following topics: * Software architecture: component-based software, (D)COM, Corba, JINI, distributed systems. * Security: formalisation and verification of security properties, transaction processing. * Language design: advanced type systems, generic programming, intermediate languages. * Language implementation: interoperability, platform independent run-time systems, program transformation. * Scripting: domain specific languages, e-commerce. Applications will be evaluated from now on until the positions are filled. To apply (or for further details) please send email to Erik Meijer (mailto:erik@cs.uu.nl) Your email application should include a CV (ascii or postscript) and pointers to any on-line articles that you wish us to consider. Please can you also include names and email addresses of potential referees. From cat-dist Thu Sep 2 13:03:35 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id KAA24868 for categories-list; Thu, 2 Sep 1999 10:47:28 -0300 (ADT) X-Authentication-Warning: mailserv.mta.ca: Majordom set sender to cat-dist@mta.ca using -f X-Received: from porky.mta.ca (porky.mta.ca [138.73.101.9]) by mailserv.mta.ca (8.9.3/8.9.3) with SMTP id WAA06776 for ; Wed, 1 Sep 1999 22:28:46 -0300 (ADT) X-Received: FROM kundry.uchicago.edu BY porky.mta.ca ; Wed Sep 01 22:34:58 1999 X-Received: (from may@localhost) by kundry.uchicago.edu (8.9.2/8.9.2) id UAA15429; Wed, 1 Sep 1999 20:28:19 -0500 (CDT) Date: Wed, 1 Sep 1999 20:28:19 -0500 (CDT) From: Peter May Message-Id: <199909020128.UAA15429@kundry.uchicago.edu> To: categories@mta.ca Subject: categories: MAC LANE FEST SCHEDULE Sender: cat-dist@mta.ca Precedence: bulk Status: RO X-Status: MAC LANE FEST SCHEDULE DEPARTMENT OF MATHEMATICS THE UNIVERSITY OF CHICAGO All talks will be in Eckhardt 206 FRIDAY, OCTOBER 8: 2:30 Irving Kaplansky: Valuation rings and other things 3:30 Tea 4:00 Israel Singer: TBA 6:00 Banquet at the Quadrangle Club SATURDAY, OCTOBER 9: 9:30 Coffee and donuts 10:00 David Eisenbud: An exterior view of sheaves on projective space 11:15 Ieke Moerdijk: Operads, monads, and Hopf algebras 2:00 Anil Nerode: Logic with Mac Lane in the 1950's 3:30 Matters categorical: Peter Freyd, William Lawvere, and others SUNDAY, OCTOBER 10: 9:30 Coffee and donuts 10:00 Richard Kadison: Eilenberg-MacLane Cohomology -- Some Applications in Functional Analysis 11:15 Steve Awodey: Mac Lane set theory 2:00 Peter May: Picard groups, Grothendieck rings, and Burnside rings of symmetric monoidal categories 3:30 Reminiscenses: tutti Please e-mail Dorothy Frazier, dorothy@math.uchicago.edu, to let us know if you wish to attend the banquet. (There will be a $30 charge.) From cat-dist Tue Sep 7 17:21:52 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id PAA10831 for categories-list; Tue, 7 Sep 1999 15:42:58 -0300 (ADT) X-Authentication-Warning: triples.math.mcgill.ca: barr owned process doing -bs Date: Tue, 7 Sep 1999 13:50:42 -0400 (EDT) From: Michael Barr X-Sender: barr@triples.math.mcgill.ca To: Categories list Subject: categories: Re: John Isbell Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: cat-dist@mta.ca Precedence: bulk Status: RO X-Status: I wrote to Jack Duskin and asked for news on Isbell. This is his reply. I very much regret that I think the John Isbell we all knew and respected enormously is probably gone forever. The person may still be there, but the mathematician is probably not and that is what made him what he was. Michael ---------- Forwarded message ---------- Date: Sat, 4 Sep 1999 10:14:21 -0400 From: John Duskin To: Michael Barr Subject: Re: John Isbell I saw John yesterday and for the first time it was clear that he recognized me as soon as I walked in by greeting me by name. He is still very weak and drifts in and out. There have been some setbacks, but on the whole, he is still making progress. They hope to transfer him to rehab center near his appartment as soon as he gets a little more strength. Keep your fingers crossed! I will see him again on Sunday. Regards, Jack From cat-dist Tue Sep 7 17:24:34 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id PAA10814 for categories-list; Tue, 7 Sep 1999 15:41:18 -0300 (ADT) X-Authentication-Warning: mailserv.mta.ca: Majordom set sender to cat-dist@mta.ca using -f Date: Mon, 6 Sep 1999 16:27:47 +0200 (MET DST) X-Sender: gran@mail.math.ucl.ac.be Message-Id: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" X-Mailer: Eudora F1.5.3 To: categories@mta.ca From: gran@agel.ucl.ac.be (Marino Gran) Subject: categories: PSSL 71: Second Announcement Sender: cat-dist@mta.ca Precedence: bulk Status: RO X-Status: PERIPATETIC SEMINAR ON SHEAVES AND LOGIC 71st meeting -- Second Announcement The 71st meeting of the PSSL will be held in Louvain-la-Neuve on the weekend of 16-17 October 1999. We welcome contributed talks on category theory and related areas. Talks on Saturday 16 October will be organized at "Le Bois des Reves", a nice place close to Louvain-la-Neuve. Lunch and dinner will be offered there to all participants who have announced their participation by October 4 (sorry, we are unable to escape this restriction). Talks on Sunday morning will be organized in a lecture room close to the Residence Le Relais and the Louvain-la-Neuve railway station. Those interested in attending the meeting should complete the registration form below and return it as soon as possible to gran@agel.ucl.ac.be ACCOMMODATION Two kinds of accommodation are available: 1. At the "Residence Le Relais", rue de la Gare 6, LLN Tel. 010 / 486565 Fax 010 / 486550 in the centre of Louvain-la-Neuve. Prices start at 950 BEF per night (single room). You can find further information at the address http://www.relais.ucl.ac.be 2. At the "Hotel de Lauzelle", avenue de Lauzelle 61, LLN Tel. 010 / 450751 Fax 010 / 450911 located at walking distance from the centre (10 minutes). The prices are: -2550 BEF for a single room -2900 BEF for a double room You can book a room personally (using the electronic reservation form for the "Le Relais") or you can ask us to make a reservation for you. In any case please fill in the registration form below and return it by October 4. More details, including a programme, will be sent out a week before the meeting to those who have registered. With very best regards, Francis Borceux Marino Gran Mamuka Jibladze Enrico Vitale ----------------------------------------------------------------------- PSSL 71 -- REGISTRATION FORM Name: Address: E-mail: I wish to attend the 71st meeting of the PSSL. *I should like to give a talk entitled: *Please reserve accommodation for me - At the "Residence Le Relais" for Friday/Saturday/Sunday night(s) - At the "Hotel de Lauzelle" for Friday/Saturday/Sunday night(s) *I have reserved accommodation on my own - At the "Residence Le Relais" for Friday/Saturday/Sunday night(s) - At the "Hotel de Lauzelle" for Friday/Saturday/Sunday night(s) *Please reserve for me * lunch on Saturday * dinner on Saturday *Delete if inappropriate. ------------------------------------------------------------------------ From cat-dist Wed Sep 8 16:13:36 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id OAA23542 for categories-list; Wed, 8 Sep 1999 14:55:55 -0300 (ADT) X-Authentication-Warning: triples.math.mcgill.ca: barr owned process doing -bs Date: Wed, 8 Sep 1999 12:46:38 -0400 (EDT) From: Michael Barr X-Sender: barr@triples.math.mcgill.ca To: Categories list Subject: categories: John Isbell Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: cat-dist@mta.ca Precedence: bulk Status: O X-Status: Jack writes me that I am being overly pessimistic and that people have been in a coma for months, then in rehab for a year or more have fully recovered. May it come to pass. Michael From cat-dist Wed Sep 8 16:18:12 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id OAA23024 for categories-list; Wed, 8 Sep 1999 14:57:02 -0300 (ADT) X-Authentication-Warning: triples.math.mcgill.ca: barr owned process doing -bs Date: Wed, 8 Sep 1999 13:10:21 -0400 (EDT) From: Michael Barr X-Sender: barr@triples.math.mcgill.ca To: Categories list Subject: categories: John Isbell (fwd) Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=X-UNKNOWN Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from QUOTED-PRINTABLE to 8bit by mailserv.mta.ca id OAA19576 Sender: cat-dist@mta.ca Precedence: bulk Status: O X-Status: Jack has asked me to post the following: ---------- Forwarded message ---------- Date: Wed, 8 Sep 1999 10:48:12 -0400 From: John Duskin To: Michael Barr Subject: John Isbell Mike perhaps you could post this to the net as a reply to your , I feel, overly pessimistic view of John's condition: Mike, your pessimistic view of John's condition is not shared by those of us who have seen him in Buffalo. People who have been in a prolonged coma may take months to return to normal functioning and even then require equally long periods of rehabilitation. René Lavendhomme told me this summer about his experience and mental confusion after a prolonged coma..."and then I even had to re-learn to walk!". People who know him now would never know that he had had such a terrible experience. I hope that that will be the case with John as well. Knowing him I can well imagine him quoting Mark Twain to us: " The reports of my demise have been greatly exaggerated." From cat-dist Thu Sep 9 11:26:27 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id JAA20439 for categories-list; Thu, 9 Sep 1999 09:40:43 -0300 (ADT) X-Authentication-Warning: triples.math.mcgill.ca: barr owned process doing -bs Date: Wed, 8 Sep 1999 10:12:06 -0400 (EDT) From: Michael Barr X-Sender: barr@triples.math.mcgill.ca To: Categories list Subject: categories: nonpareil dinats Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: cat-dist@mta.ca Precedence: bulk Status: RO X-Status: Here is an amusing observation, doubtless of no importance. In the middle of a talk at Boulder in, I think, 1987, Bob Pare' came up with a class of exotic dinatural endotransformations on the homfunctor on Set. Namely, for an endomorphism t: X --> X, let t |--> n where n depends only the cardinality of the fixpoint set of t. Since, for f: X --> Y and g: Y --> X, fg and gf have isomorphic fixpoint sets, this turns out to be dinatural. The fact that Fix(fg) is isomoprhic to Fix(gf) is perfectly general in any category that has the equalizer used to define them. In particular, this is true in Set\op and so we can get non-Pare' dinats by using the same formula, but making n depend instead on the cofixpoint set of t, where that is the coequalizer of t and the identity. It is easy to find examples of endomorphisms that have the same fixpoint set, but different cofixpoint sets and vice versa, so tere are genuinely new. Are there any others? I don't know. I started thinking about this after a note from Vaughan Pratt who was interested in Chu(Set,2) (Surprise!). He had noted that there was a full subcategory of chusets of the form (A,0) and you could treat their endomorphisms separately. That full subcategory is essentially Set and so you on that subcategory you can use all the Pare' and non-Pare' dinats. Leaving those aside, you can do dinatural endotransformations of the internal hom functor in four ways: If (A,X) is an object, then an internal endoarrow is a 4-tuple (f,s,a,x) where f: A --> A, s: X --> X, a in A and x in X subject to = for all a in A and all x in X. The nth power of such a 4-tuple is simply . Then you can define dinats by letting (f,s,a,x) |--> (f,s,a,x)^n where n depends on Fix(f) and Fix(s) OR on Cofix(f) and Cofix(s) OR on Fix(f) and Cofix(s) OR on Cofix(f) and Fix(s). Qeustion: Are there any dinats on the internal homfunctor on vector spaces? I almost have an argument for finite dimensional spaces, but it depends on writing every endomorphism as a sum of rank one endomorphisms. Michael From cat-dist Thu Sep 9 14:59:53 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id NAA27917 for categories-list; Thu, 9 Sep 1999 13:41:31 -0300 (ADT) X-Authentication-Warning: mailserv.mta.ca: Majordom set sender to cat-dist@mta.ca using -f Message-ID: <37D670B8.A27C0161@cs.tu-berlin.de> Date: Wed, 08 Sep 1999 16:20:40 +0200 From: Claudia Ermel Organization: TU Berlin, Fachbereich Informatik X-Mailer: Mozilla 4.61 [en] (X11; U; SunOS 5.6 sun4u) X-Accept-Language: en MIME-Version: 1.0 To: categories Subject: categories: CfP: Joint APPLIGRAPH/GETGRATS Workshop on Graph Transformation Systems (GRATRA 2000) Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Sender: cat-dist@mta.ca Precedence: bulk Status: O X-Status: (Sorry if you receive multiple copies of this CFP) ------------------------------------------------------------------------- CALL FOR PAPERS Joint APPLIGRAPH/GETGRATS Workshop on Graph Transformation Systems (GRATRA 2000) March 25 - 27, as Satellite Event of ETAPS 2000, March 27 - April 1, 2000 Berlin, Germany ------------------------------------------------------------------------- http://tfs.cs.tu-berlin.de/gratra2000 http://iks.cs.tu-berlin.de/etaps2000 Submission Deadline: November 15, 1999 OBJECTIVES OF THE WORKSHOP -------------------------- Graphical representations and graphs are extremely useful to model complex structures in many fields of computer science. Graph transformation is the rule-based manipulation of such graphs. The final workshop of APPLIGRAPH and GETGRATS intends to bring together leading researchers in theory and application of graph transformation and researchers in other areas of ETAPS who are interested in graph transformation. For this reason, this workshop is not restricted to members of the teams of APPLIGRAPH and GETGRATS, but open for anybody. The contributions during the workshop will be based on extended abstracts selected by an international program committee. After the workshop two special issues of journals will be published focusing on selected contributions of the workshop. Further Information: APPLIGRAPH: http://www.informatik.uni-bremen.de/grp/ag-ti/appligraph/ GETGRATS: http://www.di.unipi.it/~andrea/GETGRATS/ MAIN TOPICS ----------- Major topics of interest include but are not limited to the following: Fundamentals: Node, edge and hyperedge replacement, algebraic and logical approaches, term graph rewriting, graph theoretical properties, concurrency, distributivity and semantics, high-level replacement systems, structuring concepts, analysis techniques for graphs and graph transformation. Applications: languages and tools based on graph transformation, application of graph transformation to visual languages, database and information systems, concurrent and distributed systems, CSCW, distributed business process reengineering, design/implementation of programming languages, software engineering. FORM AND SIZE OF CONTRIBUTIONS ------------------------------ Submitted extended abstracts of about 8 LNCS pages should report recent and ongoing research work. Electronic submission to gratra2000@tfs.cs.tu-berlin.de is strongly recommended. We would like to encourage people to submit full papers to the main conferences of ETAPS 2000 and allow to have extended abstracts of the the same subject as submission for GRATRA 2000, in parallel. If both are accepted, the lecture will be held at the ETAPS conference, but also announced during GRATRA 2000. IMPORTANT DATES --------------- November 15, 1999 - Deadline for Submission of Extended Abstracts January 20, 2000 - Notification of Acceptance/ Rejection February 20, 2000 - Final Version of Extended Abstract PROGRAM COMMITTEE ----------------- M. Bauderon (LaBRI Bordeaux, F), A. Corradini (University of Pisa, I), H. Ehrig (TU Berlin, D) (chair), G. Engels (University of Paderborn, D), D. Janssens (University of Antwerp, B), H.-J. Kreowski (University of Bremen, D), U. Montanari (University of Pisa, I), M. Nagl (RWTH Aachen,D), F. Parisi-Presicce (University of Rome, I), R. Plasmeijer (University of Nijmegen, NL), D. Plump (University of Bremen, D), G. Rozenberg (University of Leiden, NL), G. Taentzer (TU Berlin, D) LOCAL ADDRESS ------------- Prof. Dr. H. Ehrig Institut für Kommunikation und Softwaretechnik Sekr. FR 6-1 TU Berlin Franklinstr. 28/29 D-10587 Berlin, Tel: 49-30-314-73510 Contact: Hartmut Ehrig, gratra2000@tfs.cs.tu-berlin.de ORGANIZERS ---------- The area of graph transformation is supported by the TMR Research Network GETGRATS (General Theory of Graph Transformation Systems) where the emphasis is on theoretical aspects and on training of young researchers. It is further supported by the ESPRIT Working Group APPLIGRAPH (Applications of Graph Transformation). This workshop is a joint workshop of APPLIGRAPH and GETGRATS. It is organized as satellite event of the conference ETAPS 2000 (European Joint Conferences on Theory and Practice of Software) at the Technische Universität Berlin. The workshop is organized by H. Ehrig and G. Taentzer (local organizers) in cooperation with A. Corradini (GETGRATS coordinator) and H.-J. Kreowski (APPLIGRAPH coordinator). -- E-mail: gratra2000@tfs.cs.tu-berlin.de From cat-dist Thu Sep 9 18:33:14 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id RAA15124 for categories-list; Thu, 9 Sep 1999 17:28:03 -0300 (ADT) X-Authentication-Warning: mailserv.mta.ca: Majordom set sender to cat-dist@mta.ca using -f MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <14287.61166.861408.599625@turing.loria.fr> Date: Fri, 3 Sep 1999 17:53:18 +0200 (MET DST) From: Christophe Ringeissen To: categories@mta.ca Subject: categories: FroCoS'2000: Third Call for Papers X-Mailer: VM 6.51 under 20.4 "Emerald" XEmacs Lucid Reply-To: Christophe.Ringeissen@loria.fr Sender: cat-dist@mta.ca Precedence: bulk Status: O X-Status: [We apologize for multiple copies] Third Call for Papers Third International Workshop ``Frontiers of Combining Systems'' FroCoS'2000 March 22-24, 2000, Nancy, France http://www.loria.fr/conferences/frocos2000/ DEADLINE FOR PAPER SUBMISSIONS: OCTOBER 1, 1999 *************** In various areas of computer science, such as logic, computation, program development and proof, artificial intelligence, there is an obvious need for using specialized formalisms and inference mechanisms for special tasks. In order to be usable in practice, these specialized systems must be combined with each other, and they must be integrated into general purpose systems. The development of general techniques for the combination and integration of special systems has been initiated in many areas. The two previous international workshops on ``Frontiers of Combining Systems'' were held in Munich (1996) and in Amsterdam (1998). Like its predecessors, FroCoS'2000 is intended to offer a common forum for research activities in the general area of combination and integration of systems, and on their practical use. Suggested, but not exclusive topics of interest for the workshop are: * combination of logics * combination of constraint solving techniques, of decision procedures, of term rewriting systems * combination of deduction systems and computer algebra * integration of decision procedures and other solving processes into constraint programming and deduction systems * modelisation of hybrid systems * logic modelling of multi-agent systems. We expect to attract high quality original papers that cover relevant aspects of these topics. All submissions will be thoroughly evaluated. On the basis of the referee reports, papers will be selected for presentation at the conference and for the published post-conference proceedings. Invited Speakers: G. Dowek (INRIA Rocquencourt) K. Schulz (LMU Muenchen) T. Uribe (Stanford U.) R. Zippel (IDC Herzliya) Program Committee: F. Baader (RWTH Aachen) D. Basin (U. Freiburg) F. Benhamou (U. Nantes) T. Fruehwirth (LMU Muenchen) F. Giunchiglia (ITC-IRST Trento) B. Gramlich (TU Wien) H. Kirchner (LORIA Nancy) C. Kreitz (Cornell U.) T. Mossakowski (U. Bremen) J. Pfalzgraf (U. Salzburg) M. de Rijke (U. Amsterdam) C. Ringeissen (LORIA Nancy) T. Scott (U. Paderborn/INRIA) M. Wallace (IC-Parc London) Program Chairs: H. Kirchner and C. Ringeissen LORIA & INRIA-Lorraine Campus Scientifique - BP 239 54506 Vandoeuvre-les-Nancy Cedex France E-mail: frocos@loria.fr Local Organization: C. Bergeret, A.-L. Charbonnier, A. Demange, H. Kirchner, C. Ringeissen, L. Vigneron. Paper Submissions: Authors are encouraged to use LaTeX and the standard article class/style file (10pt). The primary means of submission will be electronic, in PostScript format. Papers should be compressed, then uuencoded, and e-mailed to the program chairs. Papers should not exceed 15 pages, and should be received via e-mail by October 1, 1999. Results must be unpublished, and not submitted for publication elsewhere. Submissions should start with title, author(s) (names, correspondence addresses, e-mail addresses), and abstract. Important Dates: Paper Submissions: October 1, 1999 E-mail for paper submissions: frocos@loria.fr Notification of Acceptance: December 20, 1999 Final Versions due: February 5, 2000 Conference: March 22-24, 2000 FroCoS'2000 is just before ETAPS'2000 (Berlin, March 25-April 2,2000) so that attendance to both conferences can be suitably combined. Information on FroCoS'2000 is available by WWW: http://www.loria.fr/conferences/frocos2000/ From cat-dist Wed Sep 15 21:38:03 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id UAA11998 for categories-list; Wed, 15 Sep 1999 20:08:43 -0300 (ADT) X-Authentication-Warning: mailserv.mta.ca: Majordom set sender to cat-dist@mta.ca using -f Date: Wed, 15 Sep 1999 19:02:00 -0400 From: Michael MAKKAI To: categories@mta.ca Subject: categories: paper announcement Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: cat-dist@mta.ca Precedence: bulk Status: RO X-Status: I am announcing a paper, and enclose an (somewhat) extended abstract. The paper is available at the site ftp://ftp.math.mcgill.ca/pub/makkai , the name of the file is mltomcat.zip . It is a ZIPPED package of 8 POSTSCRIPT files. When accessed through NETSCAPE, there was no difficulty getting it; but with ordinary ftp-ing, we couldn't get to it. The problems with the ftp sites here at McGill are being looked at, but they are not solved yet. The multitopic omega-category of all multitopic omega-categories by M. Makkai (McGill University) September 2, 1999 Abstract The paper gives two definitions: that of "multitopic omega-category" and that of "the (large) multitopic set of all (small) multitopic omega-categories". It also announces the theorem that the latter is a multitopic omega-category. (The proof of the theorem will be contained in a sequel to this paper.) The work has two direct sources. One is the paper [H/M/P] (for the references, see at the end of this abstract) in which, among others, the concept of "multitopic set" was introduced. The other is the present author's work on FOLDS, First Order Logic with Dependent Sorts. The latter was reported on in [M2]. A detailed account of the work on FOLDS is in [M3]. For the understanding of the present paper, what is contained in [M2] suffices. In fact, section 1 of the present paper gives the definitions of all that's needed in this paper; so, probably, there won't be even a need to consult [M2]. The concept of multitopic set, the main contribution of [H/M/P], was, in turn, inspired by the work of J. Baez and J. Dolan [B/D]. Multitopic sets are a variant of opetopic sets of loc. cit. The name "multitopic set" refers to multicategories, a concept originally due to J. Lambek [L], and given an only moderately generalized formulation in [H/M/P]. The earlier "opetopic set" of [B/D] is based on a concept of operad. I should say that the exact relationship of the two concepts ("multitopic set" and "opetopic set") is still not clarified. The main aspect in which the theory of multitopic sets is in a more advanced state than that of opetopic sets is that, in [H/M/P], there is an explicitly defined category Mlt of *multitopes*, with the property that the category of multitopic sets is equivalent to the category of Set-valued functors on Mlt, a result given a detailed proof in [H/M/P]. The corresponding statement on opetopic sets and opetopes is asserted in [B/D], but the category of opetopes is not described. In this paper, the category of multitopes plays a basic role. Multitopic sets and multitopes are described in section 2 of this paper; for a complete treatment, the paper [H/M/P] should be consulted. The indebtedness of the present work to the work of Baez and Dolan goes further than that of [H/M/P]. The second ingredient of the Baez/Dolan definition, after "opetopic set", is the concept of "universal cell". The Baez/Dolan definition of weak n-category achieves the remarkable feat of specifying the composition structure by universal properties taking place in an opetopic set. In particular, a (weak) opetopic (higher-dimensional) category is an opetopic set with additional properties ( but with no additional data), the main one of the additional properties being the existence of sufficiently many universal cells. This is closely analogous to the way concepts like "elementary topos" are specified by universal properties: in our situation, "multitopic set" plays the "role of the base" played by "category" in the definition of "elementary topos". In [H/M/P], no universal cells are defined, although it was mentioned that their definition could be supplied without much difficulty by imitating [B/D]. In this paper, the "universal (composition) structure" is supplied by using the concept of FOLDS-equivalence of [M2]. In [M2], the concepts of "FOLDS-signature" and "FOLDS-equivalence" are introduced. A (FOLDS-) signature is a category with certain special properties. For a signature L , an *L-structure* is a Set-valued functor on L. To each signature L, a particular relation between two variable L-structures, called L-equivalence, is defined. Two L-structures M, N, are L-equivalent iff there is a so-called L-equivalence span M<---P--->N between them; here, the arrows are ordinary natural trasnformations, required to satisfy a certain property called "fiberwise surjectivity". The slogan of the work [M2], [M3] on FOLDS is that *all meaningful properties of L-structures are invariant under L-equivalence*. As with all slogans, it is both a normative statement ("you should not look at properties of L-structures that are not invariant under L-equivalence"), and a statement of fact, namely that the "interesting" properties of L-structures are in fact invariant under L-equivalence. (For some slogans, the "statement of fact" may be false.) The usual concepts of "equivalence" in category theory, including the higher dimensional ones such as "biequivalence", are special cases of L-equivalence, upon suitable, and natural, choices of the signature L; [M3] works out several examples of this. Thus, in these cases, the slogan above becomes a tenet widely held true by category theorists. I claim its validity in the generality stated above. The main effort in [M3] goes into specifying a language, First Order Logic with Dependent Sorts, and showing that the first order properties invariant under L-equivalence are precisely the ones that can be defined in FOLDS. In this paper, the language of FOLDS plays no role. The concepts of "FOLDS-signature" and "FOLDS-equivalence" are fully described in section 1 of this paper. The definition of *multitopic omega-category* goes, in outline, as follows. For an arbitrary multitope SIGMA of dimension >=2, for a multitopic set S, for a pasting diagram ALPHA in S of shape the domain of SIGMA and a cell a in S of the shape the codomain of SIGMA, such that a and ALPHA are parallel, we define what it means to say that a is a *composite* of ALPHA. First, we define an auxiliary FOLDS signature L extending Mlt, the signature of multitopic sets. Next, we define structures S and S, both of the signature L, the first constructed from the data S and a , the second from S and ALPHA, both structures extending S itself. We say that a is a composite of ALPHA if there is a FOLDS-equivalence-span E between S and S that restricts to the identity equivalence-span from S to S . Below, I'll refer to E as an *equipment* for a being a composite of ALPHA. A multitopic set is a *mulitopic omega-category* iff every pasting diagram ALPHA in it has at least one composite. The analog of the universal arrows in the Baez/Dolan style definition is as follows. A *universal arrow* is defined to be an arrow of the form b:ALPHA-----> a where a is a composite of ALPHA via an equipment E that relates b with the identity arrow on a : in turn, the identity arrow on a is any composite of the empty pasting diagram of dimension dim(a)+1 based on a . Note that the main definition does *not* go through first defining "universal arrow". A new feature in the present treatment is that it aims directly at weak *omega*-categories; the finite dimensional ones are obtained as truncated versions of the full concept. The treatment in [B/D] concerns finite dimensional weak categories. It is important to emphasize that a multitopic omega category is still just a multitopic set with additional properties, but with no extra data. The definition of "multitopic omega-category" is given is section 5; it uses sections 1, 2 and 4, but not section 3. The second main thing done in this paper is the definition of MltOmegaCat. This is a particular large multitopic set. Its definition is completed only by the end of the paper. The 0-cells of MltOmegaCat are the samll multitopic omega-categories, defined in section 5. Its 1-cells, which we call 1-transfors (thereby borrowing, and altering the meaning of, a term used by Sjoerd Crans [Cr]) are what stand for "morphisms", or "functors", of multitopic omega-categories. For instance, in the 2-dimensional case, multitopic 2-categories correspond to ordinary bicategories by a certain process of "cleavage", and the 1-transfors correspond to homomorphisms of bicategories [Be]. There are n-dimensional transfors for each n in N . For each multitope (that is, "shape" of a higher dimensional cell) PI, we have the *PI-transfors*, the cells of shape PI in MltOmegaCat. For each fixed multitope PI, a PI-transfor is a *PI-colored multitopic set* with additional properties. "PI-colored multitopic sets" are defined in section 3; when PI is the unique zero-dimensional multitope, PI-colored multitopic sets are the same as ordinary multitopic sets. Thus, the definition of a transfor of an arbitrary dimension and shape is a generalization of that of "multitopic omega-category"; the additional properties are also similar, they being defined by FOLDS-based universal properties. There is one new element though. For dim(PI)>=2 , the concept of PI-transfor involves a universal property which is an omega-dimensional, FOLDS-style generalization of the concept of right Kan-extension (right lifting in the terminology used by Ross Street). This is a "right-adjoint" type universal property, in contrast to the "left-adjoint" type involved in the concept of composite (which is a generalization of the usual tensor product in modules). The main theorem, stated but not proved here, is that MltOmegaCat is a multitopic omega-category. The material in this paper has been applied to give formulations of omega-dimensional versions of various concepts of homotopy theory; details will appear elesewhere. I thank Victor Harnik and Marek Zawadowski for many stimulating discussions and helpful suggestions. I thank the members of the Montreal Category Seminar for their interest in the subject of this paper, which made the exposition of the material at a time when it was still in an unfinished state a very enjoyable and useful process for me. References: [B/D] J. C. Baez and J. Dolan, Higher-dimensional algebra III. n-categories and the algebra of opetopes. Advances in Mathematics 135 (1998), 145-206. [Be] J. Benabou, Introduction to bicategories. In: Lecture Notes in Mathematics 47 (1967), 1-77 (Springer-Verlag). [Cr] S. Crans, Localizations of transfors. Macquarie Mathematics Reports no. 98/237. [H/M/P] C. Hermida, M. Makkai and J. Power, On weak higher dimensional categories I. Accepted by: Journal of Pure and Applied Algebra. Available electronically (when the machines work ...). [L] J. Lambek, Deductive systems and categories II. Lecture Notes in Mathematics 86 (1969), 76-122 (Springer-Verlag). [M2] M. Makkai, Towards a categorical foundation of mathematics. In: Logic Colloquium '95 (J. A. Makowski and E. V. Ravve, editors). Lecture Notes in Logic 11 (1998) (Springer-Verlag). [M3] M. Makkai, First Order Logic with Dependent Sorts. Research momograph, accepted by Lecture Notes in Logic (Springer-Verlag). Under revision. Original form available electronically (when the machines work ...). Cheers: M. Makkai From cat-dist Thu Sep 16 13:19:04 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id LAA08597 for categories-list; Thu, 16 Sep 1999 11:26:16 -0300 (ADT) X-Authentication-Warning: mailserv.mta.ca: Majordom set sender to cat-dist@mta.ca using -f Date: Wed, 15 Sep 1999 21:45:42 -0700 (PDT) Message-Id: <199909160445.VAA06332@Steam.Stanford.EDU> From: Carolyn Talcott To: categories@mta.ca Subject: categories: FMOODS 2000 CFP correction Reply-to: clt@cs.stanford.edu Sender: cat-dist@mta.ca Precedence: bulk Status: RO X-Status: [[many apologies for duplication both in mailing list and mailing. In the previous announcement the conference dates were wrong. The correct dates are Wed-Fri 6th-8th September 2000]] %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Preliminary Call for Papers Fourth IFIP International conference on Formal Methods for Open Object-based Distributed Systems FMOODS'2000 Stanford California, USA, 6th-8th September, 2000 ------------------------------------------------------------------------ [ balance of message not resent, see previous post...moderator] ... From cat-dist Thu Sep 16 13:25:29 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id LAA02540 for categories-list; Thu, 16 Sep 1999 11:22:29 -0300 (ADT) X-Authentication-Warning: mailserv.mta.ca: Majordom set sender to cat-dist@mta.ca using -f Date: Wed, 15 Sep 1999 12:53:25 -0700 (PDT) Message-Id: <199909151953.MAA02440@Steam.Stanford.EDU> From: Carolyn Talcott To: categories@mta.ca Subject: categories: FMOODS 2000 Preliminary Call for Papers Reply-to: clt@cs.stanford.edu Sender: cat-dist@mta.ca Precedence: bulk Status: RO X-Status: Preliminary Call for Papers Fourth IFIP International conference on Formal Methods for Open Object-based Distributed Systems FMOODS'2000 Stanford California, USA, 4th-6th September, 2000 ------------------------------------------------------------------------ Objectives Object-based Distributed Computing is being established as the most pertinent basis for the support of large, heterogeneous computing and telecommunications systems. Indeed, several important international organisations, such as ITU, ISO, OMG, TINA-C, etc. are defining similar distributed object-based frameworks as a foundation for open distributed computing. The advent of Open Object-based Distributed Systems - OODS - brings new challenges and opportunities for the use and development of formal methods. New architectures and system models are emerging (e.g., the enterprise, information, computational and engineering viewpoints of the ITU-T/ISO/IEC ODP Reference Model) which require formal notational support. Usual design issues such as specification, verification, refinement, and testing need to take into account new dimensions introduced by distribution and openness, such as quality of service and dependability constraints, dynamic binding and reconfiguration, consistency between multiple models and viewpoints, etc. OODS is a challenging research context and a source of motivation for semantical models of object-based systems and notations, for the evolution of standardised formal description techniques, for the application and assessment of logic based approaches, for better understanding and information modeling of business requirements, and for the further development and use of Object Oriented methodologies and tools. The objective of FMOODS is to provide an integrated forum for the presentation of research in several related fields, and the exchange of ideas and experiences in the topics concerned with the formal methods support for Open Object-based Distributed Systems. Topics Topics of interest include but are not limited to: * formal models for object-based distributed computing * semantics of object-based distributed systems and programming languages * formal techniques in object-based and object-oriented specification, analysis and design * refinement and transformation of specifications * types, service types and subtyping * interoperability and composability of distributed services * object-based coordination languages * object-based mobile languages * efficient analysis techniques of specifications * multiple viewpoint modelling and consistency between different models * formal techniques in distributed systems verification and testing * specification, verification and testing of quality of service constraints * formal methods and object life cycle * beyond IDL: semantics based specification patterns * formal models for measuring the quality of object-oriented requirement or design specifications * formal aspects of distributed real-time multimedia systems * applications to telecommunications and related areas Sponsors - IFIP Conference Organizers Carolyn Talcott, General Chair Stanford University clt@cs.stanford.edu Sriram Sankar Metamata Inc. sriram.sankar@metamata.com Scott Smith (Pc co-chair) Johns Hopkins University scott@cs.jhu.edu Nalini Venkatasubramanian University of California, Irvine nalini@ics.uci.edu Evaluation and Publication of Submitted Papers Submitted manuscripts will be evaluated and selected for presentation in the conference. The proceedings of FMOODS 2000 will be published by Kluwer who are the publishers of IFIP events. The proceedings will be made available at the conference. Instructions to the Authors Authors are invited to submit full original research papers, up to 16 pages (including bibliography), 12 point, single spaced, including an informative abstract, names and affiliations of all authors, and a list of keywords facilitating the assignment of papers to referees. Important Dates 1st March 2000 Submission deadline 30th April 2000 Notification of acceptance 23rd May 2000 Camera ready copy for participants proceedings due Submission Procedure Information: to appear From cat-dist Thu Sep 16 16:28:34 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id OAA16011 for categories-list; Thu, 16 Sep 1999 14:30:04 -0300 (ADT) X-Authentication-Warning: mailserv.mta.ca: Majordom set sender to cat-dist@mta.ca using -f Date: Thu, 16 Sep 1999 12:15:16 -0400 From: Michael MAKKAI To: categories@mta.ca Subject: categories: announcement update Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: cat-dist@mta.ca Precedence: bulk Status: O X-Status: This is an update on the announcement I made yesterday. I announced the paper "The multitopic omega-category of all multitopic omega-categories". The site I named for it does not seem to work, however. Instead, try http://mystic.biomed.mcgill.ca/M_Makkai As I said earlier, you'll find MLTOMCAT.ZIP, a ZIPped package of 8 POSTSCRIPT files. Good luck: M. Makkai From cat-dist Mon Sep 20 13:09:20 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id KAA14432 for categories-list; Mon, 20 Sep 1999 10:45:31 -0300 (ADT) X-Authentication-Warning: mailserv.mta.ca: Majordom set sender to cat-dist@mta.ca using -f From: Application Asm Date: Thu, 16 Sep 1999 19:59:35 +0200 (MET DST) Message-Id: <199909161759.TAA01260@tec34.ethz.ch> To: categories@mta.ca Subject: categories: call for papers: ASM2000, March 19th - 24th X-Sun-Charset: ISO-8859-1 Sender: cat-dist@mta.ca Precedence: bulk Status: RO X-Status: -> We apologize if you received multiple copies of this message. <- ___________________________________________________________________________ ___________ ____________ ___________ ASM2000 ____________ ___________ http://www.tik.ee.ethz.ch/~asm/2000 ____________ ___________ Monte Verita, Switzerland March 19th - 24th 2000 ____________ ___________________________________________________________________________ In March 2000, an Abstract State Machine (ASM) Workshop (a follow up of earlier workshops, see http://www.tik.ee.ethz.ch/asm/workshops) will be held in the conference center of the Swiss Federal Institute of Technology at Monte Verita, Ticino, Switzerland, see http://www.csf-mv.ethz.ch . The ASM formalism was proposed together with the thesis that it is suitable to model arbitrary algorithms on arbitrary abstraction levels. ASMs have been used to analyze and specify various hardware- and software-systems as well as computer languages, see http://www.eecs.umich.edu/gasm . The aim of the workshop is to bring together domain-experts using ASMs as practical specification formalisms, and theoreticians using ASMs as formal starting point for their investigations. In addition the workshop is a forum on theoretical and practical topics that relate to ASMs in a broad sense. The technical program will consist of invited lectures, tutorials, presenta- tions of refereed papers, and software demonstrations. A significant part of the time will be devoted to discussions. Invited talks will be given by Andreas Blass (Univ. of Michigan), Egon Börger (Univ. of Pisa), Gerhard Goos (Univ. of Karlsruhe), Martin Odersky (EPFL Lausanne), Wolfgang Reisig (Humbold Univ. Berlin), and Natarajan Shankar (SRI International). Both extended abstracts of work in progress and full papers are welcome. Submissions of either kind must be unpublished and not submitted for publication elsewhere. We intend to publish the accepted submissions in the LNCS series. The use of the LNCS style files (available at http://www.springer.de/comp/lncs/authors.html) is strongly recommended. Submissions should be sent by November 20th, 1999 via email (postscript or pdf) to the address asm@tik.ee.ethz.ch The workshop is sponsored by the Swiss Federal Institute of Technology, Microsoft Research, and BlueCapital. Yuri Gurevich, Microsoft Research, Redmond, Washington, USA Philipp W. Kutter, Federal Institute of Technology, Zürich, Switzerland Martin Odersky, Federal Institute of Technology, Lausanne, Switzerland Lothar Thiele, Federal Institute of Technology, Zürich, Switzerland ___________________________________________________________________________ _________________________ ____________________________ _________________________ Important Dates ____________________________ ___________________________________________________________________________ Submission of contributions : November 20th, 99 Notification of acceptance : January 10th, 00 Registration deadline : March 1st, 00 Submissions of final versions : March 1st, 00 Workshop : March 19th - March 24th, 00 ASM2000 is just before ETAPS'2000 (Berlin, March 25-April 2,2000) so that attendance to both events can be suitably combined. __________________________________________________________________________ __________________________________________________________________________ ___________________________________________________________________________ _________________________ ___________________________ _________________________ Program Committee ___________________________ ___________________________________________________________________________ Andreas Blass (U. Michigan, USA) Egon Börger (U. Pisa, I) Uwe Glässer (HNI Paderborn, D) Carla P. Gomes (Cornel U./Rome Labs, USA) Georg Gottlob (TU Wien, A) Erich Grädel (U. Aachen, D) Irene Guessarian (LIAFA/U. Paris 6, F) Yuri Gurevich (co-chair, Microsoft Research, USA) Jim Huggins (Kettering U., USA) Stefan Jähnichen (GMD FIRST Berlin, D) Hans Langmaack (U. Kiehl, D.) Larry Moss (Indiana U., USA) Peter Mosses (BRIKS, DK) Martin Odersky (co-chair, EPFL Lausanne, CH) Alfonso Pierantonio (U. L'Aquila, I) Arnd Poetzsch-Heffter (FernUni Hagen, D) Dean Rosenzweig (U. of Zagreb, HR) Elvinia Riccobene (U. Catania, I) Harald Ruess (SRI International, USA) Daniel Schweizer (UBS Zuerich, CH) Anatol Slissenko (U. Paris 12, F) Lothar Thiele (co-chair, ETH Zuerich, CH) Richard Waldinger (SRI International, USA), Sasha Zamulin (Russian Akad. Science, RU) Wolf Zimmermann (U. Karlsruhe, D) __________________________________________________________________________ __________________________________________________________________________ __________________________________________________________________________ _________________________ ___________________________ _________________________ Tutorials ___________________________ __________________________________________________________________________ Tutorials include tool-demonstrations and hands-on experience with the used tools. Infrastructure includes 12 SUN-workstations. Uwe Glaesser, Giuseppe del Castillo "Specifying Concurrent Systems with ASMs" The ASM-workbench is introduced and used for experiments with concurrent systems. Harald Ruess, ... , Natarajan Shankar "Verifying ASMs with PVS" The basic features of the PVS proof development system are introduced and demonstrated. Matthias Anlauff, Philipp Kutter, Alfonso Pierantonio "Developing Domain Specific Languages" The Gem-Mex system is used to prototype and visualize small domain specific languages with ASM semantics. Further tool demos and experiments can be done during the workshop. __________________________________________________________________________ __________________________________________________________________________ From cat-dist Mon Sep 20 13:12:44 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id LAA19241 for categories-list; Mon, 20 Sep 1999 11:14:33 -0300 (ADT) X-Authentication-Warning: mailserv.mta.ca: Majordom set sender to cat-dist@mta.ca using -f Date: Sun, 19 Sep 1999 18:26:36 -0400 From: Michael MAKKAI To: categories@mta.ca Subject: categories: second update Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: cat-dist@mta.ca Precedence: bulk Status: RO X-Status: This is the second update on the paper "The multitopic omega-category of all multitopic omega-categories". The zip-file that got onto both sites I mentioned before was bad. I have now replaced it with another one which I had tested for "unzipping". The two sites: ftp://ftp.math.mcgill.ca/pub/makkai http://mystic.biomed.mcgill.ca/M_Makkai The filename is MLTOMCAT.ZIP. It is a ZIPped package of 8 POSTSCRIPT files. M. Makkai From cat-dist Mon Sep 20 16:28:35 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id OAA20716 for categories-list; Mon, 20 Sep 1999 14:28:47 -0300 (ADT) X-Authentication-Warning: mailserv.mta.ca: Majordom set sender to cat-dist@mta.ca using -f Date: Mon, 20 Sep 1999 12:06:05 -0500 (CDT) From: Hongseok Yang To: categories@mta.ca Subject: categories: Skeleton of a category Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: cat-dist@mta.ca Precedence: bulk Status: O X-Status: Would you let me know when the category has an equivalent skeleton? (The definition of the skeleton subcategory that I have in mind is from MacLane p91: a full subcategory such that for any object in the original category, there exists a unique isomorphic object in the skeleton subcategory.) My question is mainly about when I can use the choice axiom without causing contradiction. For instance, I heard that the category of abelian groups doesn't have an equivalent skeleton subcategory. Thank you very much, Hongseok From cat-dist Mon Sep 20 19:19:01 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id QAA14841 for categories-list; Mon, 20 Sep 1999 16:56:08 -0300 (ADT) X-Authentication-Warning: mailserv.mta.ca: Majordom set sender to cat-dist@mta.ca using -f Date: Mon, 20 Sep 1999 18:44:56 +0100 (BST) From: Paul Taylor Message-Id: <199909201744.SAA04812@wax.dcs.qmw.ac.uk> To: categories@mta.ca Subject: categories: Re: Skeleton of a category Sender: cat-dist@mta.ca Precedence: bulk Status: RO X-Status: > Would you let me know when the category has an equivalent skeleton? "every small category has a skeleton" iff the axiom of choice holds. See Exercise 3.26 in my book, or http://www.dcs.qmw.ac.uk/~pt/book/html/s3e.html#e3.26 for a preorder example. Exercise 4.37 defines "skeletal" http://www.dcs.qmw.ac.uk/~pt/book/html/s4e.html#e4.37 Paul From cat-dist Mon Sep 20 21:04:30 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id TAA04574 for categories-list; Mon, 20 Sep 1999 19:46:43 -0300 (ADT) X-Authentication-Warning: mailserv.mta.ca: Majordom set sender to cat-dist@mta.ca using -f From: Jiri Adamek Message-Id: <199909202149.XAA03067@lisa.iti.cs.tu-bs.de> Subject: categories: CT'99 proceedings - deadline reminder To: categories@mta.ca Date: Mon, 20 Sep 1999 23:49:26 +0200 (MET DST) X-Mailer: ELM [version 2.4ME+ PL28 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: cat-dist@mta.ca Precedence: bulk Status: RO X-Status: As announced during the conference in Coimbra, the proceedings of CT'99 will be published in the JPAA. Eligible are papers closely related to the conference talks which reach me (as a ps-file, or in 2 hard copies) by November 30. Due to space restriction, shorter paper have better chances. xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxJiri Adamek phone: 49-531-3919521 fax: 49-531-3919529 Technical University of Braunschweig e-mail: adamek@iti.cs.tu-bs.de Postfach 3329 38 023 Braunschweig, Germany WWW: http://www.iti.cs.tu-bs.de/TI-INFO//adamek/adamek.html xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx From cat-dist Tue Sep 21 10:47:12 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id JAA06471 for categories-list; Tue, 21 Sep 1999 09:00:58 -0300 (ADT) X-Authentication-Warning: mailserv.mta.ca: Majordom set sender to cat-dist@mta.ca using -f Message-ID: <000701bf0416$84736590$c2036882@uck.ac.be> From: "Mamuka Jibladze" To: Subject: categories: PSSL71 web page Date: Tue, 21 Sep 1999 11:48:53 +0200 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.00.2314.1300 X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2314.1300 Sender: cat-dist@mta.ca Precedence: bulk Status: O X-Status: Dear all, additional information concerning PSSL71 can be now found at the location http://www.math.ucl.ac.be/~jibladze/pssl71/hi.html See you at the seminar! Francis Borceux Marino Gran Mamuka Jibladze Enrico Vitale From cat-dist Tue Sep 21 14:05:17 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id LAA12892 for categories-list; Tue, 21 Sep 1999 11:38:43 -0300 (ADT) X-Authentication-Warning: mailserv.mta.ca: Majordom set sender to cat-dist@mta.ca using -f Date: Tue, 21 Sep 1999 10:29:22 -0400 (EDT) From: "R.A.G. Seely" To: Categories List Subject: categories: Web site for Octoberfest 99 Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: cat-dist@mta.ca Precedence: bulk Status: RO X-Status: Information concerning the Montreal Octoberfest, October 16-17, can be found at the site: http://www.math.mcgill.ca/triples/octoberfest99.html This will have the programme eventually, in the meantime, you can find recommendations for hotels and B&Bs, instructions for getting to the lecture site, weather information, and contact addresses. - all the best, Robert Seely ================================= From cat-dist Wed Sep 22 14:55:31 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id LAA30307 for categories-list; Wed, 22 Sep 1999 11:52:12 -0300 (ADT) X-Authentication-Warning: triples.math.mcgill.ca: rags owned process doing -bs Date: Tue, 21 Sep 1999 17:48:56 -0400 (EDT) From: "R.A.G. Seely" To: Categories List Subject: categories: URLs changing at McGill Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: cat-dist@mta.ca Precedence: bulk Status: RO X-Status: Please update all links and bookmarks to individual users's home pages at McGill in the following way: http://www.math.mcgill.ca/~user (old style) becomes http://www.math.mcgill.ca/user (new style) (note the disappearance of the tilde). (In particular, values of the variable "user" of interest to this list include: barr, bunge, makkai, rags (or seely). Lambek has a page at http://www.math.mcgill.ca/triples/lambek , but at present this only deals with a past LambekFest.) At present, in addition, the Category Group home page on triples is now http://www.math.mcgill.ca/triples - but we are hoping to soon have enabled the old version (through a virtual link) again. As some of you may have been aware, we have had some security problems at McGill, which is causing changes in our public "face". We are trying to keep these changes as "invisible" to the outside user as possible. You may (should) find that the old style urls still work, but we cannot guarantee that that will continue, so changing your links now will help. = rags = ================================= From cat-dist Wed Sep 22 16:19:17 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id OAA07472 for categories-list; Wed, 22 Sep 1999 14:25:16 -0300 (ADT) X-Authentication-Warning: mailserv.mta.ca: Majordom set sender to cat-dist@mta.ca using -f MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <14311.40697.808704.314199@turing.loria.fr> Date: Tue, 21 Sep 1999 17:06:33 +0200 (MET DST) From: Christophe Ringeissen To: categories@mta.ca Subject: categories: Last CFP: FroCoS'2000 X-Mailer: VM 6.51 under 20.4 "Emerald" XEmacs Lucid Reply-To: Christophe.Ringeissen@loria.fr Sender: cat-dist@mta.ca Precedence: bulk Status: O X-Status: [We apologize for multiple copies] !!! DEADLINE: OCTOBER 1, 1999 !!! ********************************* Last Call for Papers Third International Workshop ``Frontiers of Combining Systems'' FroCoS'2000 March 22-24, 2000, Nancy, France http://www.loria.fr/conferences/frocos2000/ !!! DEADLINE FOR PAPER SUBMISSIONS: OCTOBER 1, 1999 !!! ******************************************************* In various areas of computer science, such as logic, computation, program development and proof, artificial intelligence, there is an obvious need for using specialized formalisms and inference mechanisms for special tasks. In order to be usable in practice, these specialized systems must be combined with each other, and they must be integrated into general purpose systems. The development of general techniques for the combination and integration of special systems has been initiated in many areas. The two previous international workshops on ``Frontiers of Combining Systems'' were held in Munich (1996) and in Amsterdam (1998). Like its predecessors, FroCoS'2000 is intended to offer a common forum for research activities in the general area of combination and integration of systems, and on their practical use. Suggested, but not exclusive topics of interest for the workshop are: * combination of logics * combination of constraint solving techniques, of decision procedures, of term rewriting systems * combination of deduction systems and computer algebra * integration of decision procedures and other solving processes into constraint programming and deduction systems * modelisation of hybrid systems * logic modelling of multi-agent systems. We expect to attract high quality original papers that cover relevant aspects of these topics. All submissions will be thoroughly evaluated. On the basis of the referee reports, papers will be selected for presentation at the conference and for the published post-conference proceedings. Invited Speakers: G. Dowek (INRIA Rocquencourt) K. Schulz (LMU Muenchen) T. Uribe (Stanford U.) R. Zippel (IDC Herzliya) Program Committee: F. Baader (RWTH Aachen) D. Basin (U. Freiburg) F. Benhamou (U. Nantes) T. Fruehwirth (LMU Muenchen) F. Giunchiglia (ITC-IRST Trento) B. Gramlich (TU Wien) H. Kirchner (LORIA Nancy) C. Kreitz (Cornell U.) T. Mossakowski (U. Bremen) J. Pfalzgraf (U. Salzburg) M. de Rijke (U. Amsterdam) C. Ringeissen (LORIA Nancy) T. Scott (U. Paderborn/INRIA) M. Wallace (IC-Parc London) Program Chairs: H. Kirchner and C. Ringeissen LORIA & INRIA-Lorraine Campus Scientifique - BP 239 54506 Vandoeuvre-les-Nancy Cedex France E-mail: frocos@loria.fr Local Organization: C. Bergeret, A.-L. Charbonnier, A. Demange, H. Kirchner, C. Ringeissen, L. Vigneron. Paper Submissions: Authors are encouraged to use LaTeX and the standard article class/style file (10pt). The primary means of submission will be electronic, in PostScript format. Papers should be compressed, then uuencoded, and e-mailed to the program chairs. Papers should not exceed 15 pages, and should be received via e-mail by October 1, 1999. Results must be unpublished, and not submitted for publication elsewhere. Submissions should start with title, author(s) (names, correspondence addresses, e-mail addresses), and abstract. Important Dates: Paper Submissions: October 1, 1999 E-mail for paper submissions: frocos@loria.fr Notification of Acceptance: December 20, 1999 Final Versions due: February 5, 2000 Conference: March 22-24, 2000 FroCoS'2000 is just before ETAPS'2000 (Berlin, March 25-April 2,2000) so that attendance to both conferences can be suitably combined. Information on FroCoS'2000 is available by WWW: http://www.loria.fr/conferences/frocos2000/ From cat-dist Wed Sep 22 16:28:48 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id OAA07406 for categories-list; Wed, 22 Sep 1999 14:24:11 -0300 (ADT) X-Authentication-Warning: mailserv.mta.ca: Majordom set sender to cat-dist@mta.ca using -f Organization: Universitaet des Saarlandes, D 66123 Saarbruecken Message-Id: <199909211116.NAA16190@goedel.ags.uni-sb.de> To: categories@mta.ca, fsdm@it.uq.edu.au, softverf@leopard.cs.byu.edu, formal-methods@cs.uidaho.edu, relmics-list@heraklit.Informatik.UniBW-Muenchen.de, lics-request@research.bell-labs.com, dataloger@cs.chalmers.se, afp@cs.chalmers.se, types@cs.indiana.edu, logic@CS.Cornell.EDU, logic@theory.lcs.mit.edu, eacsl@dimi.uniud.it, eatcs-it@cs.unibo.it, mop@cs.ruu.nl, isabelle-users@cl.cam.ac.uk, info-hol@leopard.cs.byu.edu, clics@doc.ic.ac.uk, qed@mcs.anl.gov, ccl@dfki.uni-sb.de, tapsoft@dcs.ed.ac.uk, prog-lang@diku.dk, theorynt@listserv.nodak.edu, flprog@informatik.uni-muenchen.de, reliable_computing@interval.usl.edu, uitp@dcs.gla.ac.uk, facs@lboro.ac.uk, bra-types@cs.chalmers.se, coq-club@pauillac.inria.fr, ipalist@win.tue.nl, siksleden@cs.ruu.nl, asci@twi.tudelft.nl, ozsl-list@fwi.uva.nl, protagonist@cs.kun.nl, theory-a@vm1.nodak.edu, calculemus-ig@dist.unige.it, logic-ml@logic.jaist.ac.jp, theorem-provers@ai.mit.edu, ftp@logic.at, om-announce@lars.math.FSU.EDU, amast@cs.utwente.nl, rewriting@ens-lyon.fr Reply-to: Michael Kohlhase Subject: categories: CADE-17 Call for Workshops and Tutorials Date: Tue, 21 Sep 1999 13:16:13 +0200 From: Michael Kohlhase Sender: cat-dist@mta.ca Precedence: bulk Status: RO X-Status: [Apologies to all that receive this call more than once] CADE-17 The 17th International Conference on Automated Deduction June 17-20, 2000 Pittsburgh, Pennsylvania, USA http://www.research.att.com/conf/cade/ Preliminary CALL FOR WORKSHOPS AND TUTORIALS June 16. and 21. 2000 CADE is the major forum for the presentation of new research in all aspects of automated deduction. Proposals for workshops and for tutorials are solicited. Tutorials will run June 16. and workshops also on June 21. Workshops will ordinarily run a whole day, and tutorials for half a day. Workshop Topics --------------- Recent CADE workshops have included term schematizations and their applications, reasoning, automation of proofs by induction, empirical studies in logic algorithms, mechanization of partial functions, proof search in type-theoretic languages, automated model building, evaluation of automated theorem-proving systems, strategies in automated deduction, automated theorem proving in software engineering and in mathematics, integration of symbolic computation and deduction. Workshops may have the same topic as those of previous workshops, and this practice is encouraged. Tutorial Topics --------------- Recent CADE tutorials have included equality reasoning in semantic tableaux, proof systems for nonmonotonic logics, rewrite techniques in theorem proving, proof planning, parallelization of deduction strategies, resolution decision methods, constructive type theory, the use of semantics in Herbrand-based proof procedures, logical frameworks, theorem proving by the inverse method, deduction methods based on boolean rings, higher-order equational logic, and term indexing in automated reasoning. Tutorials may be introductory, intermediate, or advanced. Proposals --------- Anyone wishing to organize a workshop or tutorial in conjunction with CADE-17 should send (e-mail preferred) a proposal no longer than two pages to the workshop chair by November 30, 1999. The proposal should describe the topic of the proposed workshop or tutorial and explain why the topic is relevant to CADE. Proposals will be evaluated, and decisions will be communicated by December 15. 1999. Further information about the arrangements for workshops and tutorials can be obtained from the CADE-17 Web site. Proposal deadline: November 30, 1999 Notification of acceptance: December 15, 1999 Workshop paper deadline: April 1, 2000 Workshop paper notification: May 1, 2000 PROGRAM CHAIR: Conference Chair: WORKSHOP CHAIR: David McAllester Frank Pfenning Michael Kohlhase AT&T Labs-Research Carnegie Mellon University Universit"at des Saarlandes dmac@research.att.com fp+@cs.cmu.edu kohlhase@cs.uni-sb.de From cat-dist Thu Sep 23 16:27:37 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id NAA04342 for categories-list; Thu, 23 Sep 1999 13:58:42 -0300 (ADT) X-Authentication-Warning: mailserv.mta.ca: Majordom set sender to cat-dist@mta.ca using -f Date: Thu, 23 Sep 1999 14:09:54 +0100 (BST) From: Marta Z Kwiatkowska Message-Id: <199909231309.OAA00477@chip.cs.bham.ac.uk> To: categories@mta.ca Subject: categories: FOSSACS'2000: Call for papers Cc: M.Z.Kwiatkowska@cs.bham.ac.uk X-Sun-Charset: US-ASCII Sender: cat-dist@mta.ca Precedence: bulk Status: O X-Status: CALL FOR PAPERS FOSSACS 2000 Foundations of Software Science and Computation Structures March 27-31, 2000, Berlin, Germany http://fossacs.mimuw.edu.pl Submision deadline: October 18, 1999 A member conference of the European Joint Conferences on Theory and Practice of Software (ETAPS 2000) Conference decsription: FOSSACS seeks papers which offer progress in foundational research with a clear significance for software science. A central issue is theories and methods which support the specification, transformation, verification, and analysis of programs and software systems. Topics covered are: ** Computational and syntactic foundations of software science: computation processes over discrete and continuous data, techniques for their manipulation, and their algorithmic, algebraic, and logical properties; ** Transition systems, models of concurrency and reactive systems, and corresponding calculi, algebras, and logics; ** Type theory, domain theory, and their connections to semantics of programming languages and software specification. EATCS/EAPLS BEST PAPER AWARDS There will be two awards for the best paper among all the papers presented at any of the five main ETAPS conferences: EATCS award and EAPLS award. IMPORTANT DATES Monday 18th October 1999 Submission deadline Monday 13th December 1999 Notification of authors Thursday 13th January 2000 Final versions due March, 27 -- April, 1 2000 Conference dates INVITED SPEAKER: Abbas Edalat (Imperial College, London) SUBMISSION GUIDELINES Submitted papers must be in English and must not have appeared in, or have been submitted to, other symposia or journals. Papers should be no more than 15 pages in the Springer-Verlag LNCS style (see http://www.springer.de/comp/lncs/Authors.html for details). Electronic submissions are strongly encouraged. An electronic submission should consist of the cover letter, which contains a short abstract in plane ASCII format, and a postscript file with the paper. The postscript can be included as an attachment or can be send as a separate e-mail. Electronic submissions should be send to the address: fossacs@mimuw.edu.pl Authors will be notified by e-mail about the successful receipt of their submission. Authors without access to internet can send six hard copies of the paper to the Program Committee Chair: Jerzy Tiuryn Institue of Informatics Warsaw University Banacha 2 02-097 Warsaw, Poland PROGRAM COMMITTEE Andre Arnold (Bordeaux) Mariangiola Dezani (Torino), Harald Ganzinger (Saarbr\"{u}cken), Georg Gottlob (Vienna), Fritz Henglein (Copenhagen), Jean-Pierre Jouannaud (Orsay), Dexter Kozen (Ithaca, NY), Marta Kwiatkowska (Birmingham), Giuseppe Longo (Paris), Andrew Pitts (Cambridge), Wolfgang Thomas (Aachen), Glynn Winskel (Aarhus), Moshe Y. Vardi (Houston, TX), Jerzy Tiuryn (Warsaw, chair). From cat-dist Fri Sep 24 13:25:16 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id KAA30032 for categories-list; Fri, 24 Sep 1999 10:42:05 -0300 (ADT) X-Authentication-Warning: mailserv.mta.ca: Majordom set sender to cat-dist@mta.ca using -f X-Sender: grandis@dima.unige.it (Unverified) Message-Id: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Fri, 24 Sep 1999 10:27:48 +0100 To: categories@mta.ca From: grandis@dima.unige.it (Marco Grandis) Subject: categories: preprint: Simplicial toposes and combinatorial homotopy Sender: cat-dist@mta.ca Precedence: bulk Status: O X-Status: The following preprint is available: M. Grandis Simplicial toposes and combinatorial homotopy, Dip. Mat. Univ. Genova, Preprint 400 (1999). Abstract. The term *combinatorial topos* denotes here a topos of presheaves over a small subcategory of the category of finite sets. The main instances we want to consider are the presheaf categories of simplicial sets, cubical sets, and globular sets, together with their symmetric versions: e.g., the topos !Smp of symmetric simplicial sets consists of all presheaves on the category !Delta of finite, positive cardinals. We show here how combinatorial homotopy, developed in previous works for simplicial complexes (the cartesian closed subcategory of *simple* presheaves in !Smp) can be extended to the topos !Smp. As a crucial advantage, the (extended) fundamental groupoid Pi_1: !Smp --> Gpd is left adjoint to a natural functor M_1: Gpd --> !Smp, the symmetric nerve of a groupoid, and therefore - as a strong van Kampen property - preserves all colimits. Analogously, a notion of (non-reversible) *directed* homotopy can be developed in Smp, with applications to image analysis similar to the ones of the symmetric case. We have now a homotopy n-category functor C_n: Smp --> n-Cat, left adjoint to a nerve N_n = n-Cat(C_n(Delta[n]), -). It would be interesting to determine whether the n-category C_n(Delta[n]) coincides with Street's oriental O_n, and the previous nerve with Street's, as it seems likely. ___ Available at: ftp://pitagora.dima.unige.it/WWW/FTP/GRANDIS/CmbTop.Sep99.ps (459 K) ___ Marco Grandis Dipartimento di Matematica Universita' di Genova via Dodecaneso 35 16146 GENOVA, Italy e-mail: grandis@dima.unige.it tel: +39.010.353 6805 fax: +39.010.353 6752 http://www.dima.unige.it/STAFF/GRANDIS/ ftp://pitagora.dima.unige.it/WWW/FTP/GRANDIS/ From cat-dist Thu Sep 30 19:15:07 1999 Received: (from Majordom@localhost) by mailserv.mta.ca (8.9.3/8.9.3) id QAA27185 for categories-list; Thu, 30 Sep 1999 16:52:55 -0300 (ADT) X-Authentication-Warning: mailserv.mta.ca: Majordom set sender to cat-dist@mta.ca using -f From: Thorsten Altenkirch MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <14323.25255.175328.570387@carla.tcs.informatik.uni-muenchen.de> Date: Thu, 30 Sep 1999 15:16:23 +0200 (CEST) To: categories@mta.ca Subject: categories: CSL 2000, call for papers X-Mailer: VM 6.72 under 21.1 (patch 4) "Arches" XEmacs Lucid Sender: cat-dist@mta.ca Precedence: bulk Status: O X-Status: Apologies for multiple copies... 1st CALL FOR PAPERS -- CSL 2000 Annual Conference of the European Association for Computer Science Logic Fischbachau/Munich, Germany, August 21-26, 2000 CSL is the annual conference of the European Association for Computer Science Logic (EACSL). The conference is intended for computer scientists whose research activities involve logic, as well as for logicians working on issues significant for computer science. Suggested, but not exclusive, topics of interest are: * automated deduction and interactive theorem proving * categorical logic and topological semantics * constructive mathematics and type theory * domain theory * equational logic and term rewriting * finite model theory, database theory * higher order logic * lambda and combinatory calculi * logical aspects of computational complexity * logical foundations of programming paradigms * logic programming, constraints * linear logic * modal and temporal logics * model checking * program extraction * program logics and semantics * program specification, transformation and verification INVITED SPEAKERS Miklos Ajtai (Almaden), Paul Beame (Washington), Andreas Blass (Ann Arbor), Egon B"orger (Pisa), Yuri Gurevich (Seattle), Bruno Poizat (Lyon), Wolfram Schulte (Seattle), Saharon Shelah (Jerusalem), Colin Stirling (Edinburgh). PROGRAM COMMITTEE Edmund Clarke (Pittsburgh), Peter Clote (M"unchen), Kevin Compton (Ann Arbor), Erich Gr"adel (Aachen), Gerhard J"ager (Bern), Klaus Keimel (Darmstadt), Jan Willem Klop (Amsterdam), Jan Krajicek (Praha), Daniel Leivant (Bloomington), Tobias Nipkow (M"unchen), Helmut Schwichtenberg (M"unchen), Moshe Vardi (Houston). PAPER SUBMISSIONS Submitted papers must describe work not previously published. They must not be submitted concurrently to a journal or to another conference. Papers authored or coauthored by members of the Program Committee are not allowed. Submissions must not exceed 15 pages (in the usual format for Springer LNCS), including title page, figures and references. The title page must contain: title and authors; physical and e-mail addresses; telephone and (if available) fax number for each author; identification of corresponding author, if not the first author; an abstract of no more than 200 words; a list of keywords. Submissions must arrive by January 31, 2000. Notifications of acceptance will be sent by April 17, 2000, and final versions are due May 19, 2000. Authors are invited to send manuscripts by electronic mail, as uuencoded gzipped or attached postscript files and an ASCII file containing the abstract and the address of the corresponding author: * see the conference home page for instructions http://www.tcs.informatik.uni-muenchen.de/csl2000/ * or send a message with subject "submission information" to csl2000-org@tcs.informatik.uni-muenchen.de Concerning further questions about the submission procedure please contact Helmut Schwichtenberg schwicht@rz.mathematik.uni-muenchen.de Phone +49 89 2394 4413 Fax +49 89 280 5248 or Peter Clote clote@tcs.informatik.uni-muenchen.de Phone +49 89 2178 2241 Fax +49 89 2178 2238 PUBLICATION Papers accepted by the Program Committee must be presented at the conference and will appear in a proceedings volume, to be published by Springer Verlag in the "Lecture Notes in Computer Science" series. Final versions of accepted papers will be due by May 19, 2000. The format for camera-ready manuscripts will be that of Springer LNCS; instructions can be found in the LNCS home page at: http://www.springer.de/comp/lncs/index.html IMPORTANT DATES Paper submissions January 31, 2000 Notifications of acceptance April 17, 2000 Final version due May 19, 2000 CSL 2000 conference August 21-26, 2000 ADDITIONAL INFORMATION CSL 2000 home page: http://www.tcs.informatik.uni-muenchen.de/csl2000/ CSL 2000 local organization: csl2000-org@tcs.informatik.uni-muenchen.de