Date: Thu, 3 Mar 1994 22:12:02 +0400 (GMT+4:00) Subject: Workshop on Teaching Formal Methods Date: 02 Mar 1994 17:40:26 -0500 From: Philip Mulry Dear Colleagues, I wanted to bring to your attention the second announcement of a CS workshop on the teaching of formal methods in an undergraduate setting. My apologies that the original announcement did not appear here. If you are interested or have any questions, drop me a note. --- Philip Mulry Dept of Computer Science Colgate University Hamilton N.Y. 13346 phil@cs.colgate.edu ********************************************************************** TEACHING FORMAL METHODS CURRICULUM DEVELOPMENT WORKSHOP SECOND ANNOUNCEMENT Hamilton College Clinton, N.Y. July 30 - Aug 5, 1994 sponsored by The National Science Foundation THE PURPOSE OF THE WORKSHOP is to develop modules and materials for teaching formal methods in an undergraduate setting. Participants will be asked to submit a module or position paper which they have developed. While the particular form and length of the module is left unspecified, modules should contain both expository material and exercises or labs. TOPICS for the modules may include(but are not limited to) -- Propositional/ Predicate Calculus , with applications to assertions/pre- and post-conditions -- Loops and Invariants -- Category Theory -- Algorithm Design -- Hardware Specification/Design/Verification -- Parallel Constructs (eg. CSP, Hoare semantics) -- Operational Semantics -- Formal Methods with OOP -- Applications of Mathematica THE WORKSHOP itself will be devoted to the presentation, discussion and revision of participant modules. We also anticipate inviting several keynote speakers. After the workshop, participants will be asked to submit full revised versions of their modules for incorporation into a collection for dissemination to computer science educators. Three of the principal investigators for the project, Philip Mulry (Colgate University), Doug Troeger(CUNY) and Henry Walker(Grinnell College), will be responsible for editing the collection of materials with a view towards publication in the near future. We plan to have a followup workshop in the summer of 1995, in conjunction with the working group in Object Oriented Computing, to evaluate the results to date and further disseminate the materials developed. Participants will be encouraged to use draft versions of the modules in their teaching for evaluation. AN NSF GRANT will partially cover travel, room and board costs for the workshop. Participants will receive a stipend of $150 for their participation in the workshop and an additional $150 after submission of their revised module. THERE MAY BE LIMITED FUNDS to support attendance by individuals who want to become involved with the project but do not have a module to submit at this time. Please write to inquire. TO APPLY: Send an abstract of your module or position paper and a brief resume including your experience with formal methods to: Philip Mulry Formal Methods Workshop Computer Science Department Colgate University 13 Oak Drive Hamilton, New York 13346 email:fmworkshop@cs.colgate.edu ABSTRACTS should be no more than 5 pages in length, be clearly written, and provide sufficient detail to allow the program committee to assess the merits of the module. The preferred mode of submission is via email. The preferred abstract format is latex. Submission of abstracts should be received by March 20, 1994 by the program chair. This is a firm deadline, late submissions will not be considered. Participants will be notified of acceptance by April 1, 1994. Accepted modules (in a specified format) will be due July 1, 1994. A final revised module will be due November 1, 1994. DATES: Abstract Submission Deadline: March 20, 1994 Participation Notification: April 1, 1994 Draft Module Due: July 1, 1994 Conference: July 30 - August 5, 1994 Revised Module Due: November 1, 1994 FOR FURTHER INFORMATION, contact the Workshop Co-chairs: Philip Mulry: phil@cs.colgate.edu Doug Troeger: dtroeger@csfaculty.engr.ccny.cuny.edu Henry Walker: walker@ac.grin.edu Date: Sun, 6 Mar 1994 13:01:51 +0400 (GMT+4:00) Subject: "Sketches: Outline with References" Date: 4 Mar 1994 18:16:28 GMT From: Charles Wells My paper "Sketches: Outline with References" is now available in both TeX dvi and postscript form by anonymous FTP from ftp.cwru.edu in the directory math/wells in the file sketch.dvi or sketch.ps. I have corrected some errors in the bibliography. The corrections that were made are listed in the file skcorr.dvi or skcorr.ps. -- Charles Wells Department of Mathematics, Case Western Reserve University 10900 Euclid Avenue, Cleveland, OH 44106-7058, USA 216 368 2893 Date: Tue, 8 Mar 1994 16:40:27 +0400 (GMT+4:00) Subject: XY-pic v.2.7: Graphs and diagrams in TeX RELEASED! Date: Tue, 8 Mar 1994 21:11:11 +1000 From: Kristoffer Rose Reply to: kris@diku.dk Dear XY-pic current, former, and potential XY-pic interestees, This is to announce the release of a new version of my DIAGRAM DRAWING PACKAGE, XY-pic: version 2.7. The release is slightly overdue (16 months late, in fact) but this is due to the ABUNDANCY OF NEW FEATURES in the package. Below I have attached the TRAILER of the package that gives some more details and explains how to obtain it. If you have lost interest in XY-pic then I apologise; otherwise I hope that you'll find it worth the wait! Regards, Kristoffer Rose (.signature at the end below) ====================================================================== TRAILER: ANNOUNCING THE XY-pic version 2.7 DIAGRAM TYPESETTING PACKAGE ====================================================================== XY-pic is a package for typesetting a variety of graphs and diagrams within TeX that works with most formats (including LaTeX 2.09, LaTeX2e in compatibility mode, AMS-LaTeX, AMS-TeX, and plain TeX). XY-pic version 2.7 has been a long time underway because it is a MAJOR REWRITE of XY-pic. The reason is that the version 2.6 code has been reorganised into a kernel and several orthogonal modules to make the development of XY-pic 3 possible while maintaining backwards compatibility. Therefore * version 2.7 is a BETA TEST release in the sense that it is likely to contain bugs in both documentation and code! If you are a version 2.6 user then PLEASE TEST this release with your existing diagrams and REPORT PROBLEMS you encounter to the author: the intention is to maintain full backwards compatibility but I need feed-back from users in order to achieve this goal (see the `Incompatibilities' appendix in the User's Guide for some known problems)! * version 2.7 is an ALPHA TEST and RFC release of the forthcoming XY-pic version 3 being developed by myself in collaboration with Ross Moore while visiting Macquarie U, Sydney, until May 1994. It will add special modes for convenient specification of at least the following high-level diagram types Generalised trees, Planar graphs, Commutative diagrams with 2-cells, and String and braid diagrams, as well as provide special output drivers for at least PostScript (eliminating the need for special fonts in this case). If you wish to peek at the kind of diagrams we are working on then take a look at the files available for ftp at ftp.mpce.mq.edu.au in /pub/maths/tex/Quantum (and trough my WWW hyperlink cited below). The package will also be provided as a LaTeX2e and LaTeX3 `package' as soon as the guidelines for how to do this are available to the author. ---------------------------------------------------------------------- VERSION 2.7 FEATURES ---------------------------------------------------------------------- XY-pic version 2.7 provides two modes of specifying drawings: * A matrix-like mode where the dimensions of the drawing are automatically computed by aligning diagram entries in rows and columns (this is also the `version 2 compatibility mode'). * A general `turtle graphic' drawing language for specifying graphs with objects and connections between them in a manner independent of orientation. Both modes support the following specific features: + Positions can be given in variety of formats (extendable) including user defined coordinates (x,y) and relative to previous positions, objects, object edges, and points on connections. + Objects may be circular or rectangular (more shapes can be added) and adjusted in several ways. + Large library of objects with mnemonic names. + Objects that orient themself along a connection when placed relative to it, e.g., `\dir{|-}' is like \vdash but thus oriented. + Includes circle segments and arbitrary TeX text. + Connections are aligned between the reference points of objects but start and end on the edges. + Any object can be used to build a connection (using `diagonal filling'); library objects provide common line types. + Special notation for drawing arrows with tail, stem, and head build from any object(s). Special support for arrows that cross each other, arrows that `go by' other entries, combined arrows, and arrows with n/8 bends. + Library of frames. If you wish to check out the facilities (using a 300 dpi PostScript printer), then you can print the file `xyguide.ps' that contains a preformatted version of the User's Guide. ---------------------------------------------------------------------- AVAILABILTY ---------------------------------------------------------------------- XY-pic is available by anonymous ftp from at least the following sites: ftp.diku.dk : /diku/users/kris/TeX/xy27run.tar.Z ftp.mpce.mq.edu.au : /pub/maths/TeX/xy27run.tar.Z The same locations also contains manuals formatted for printing on 300dpi PostScript printers in `xyguide.ps.Z' and `xyrefer.ps.Z' and a special distribution for Textures (by ross@mpce.mq.edu.au) in `xy27mac.sit.hqx'; check out the README files! You can also use my WWW hyperlink cited below to retrieve the package. Please note that XY-pic is `copyleft' under the terms of the GNU General Public License. ---------------------------------------------------------------------- This is the end of the TRAILER. I hope you will enjoy XY-pic! -- Kristoffer Hxgsbro ROSE Internet: kris@diku.dk DIKU, U of Copenhagen, Universitetsparken 1, 2100 Kxbenhavn X, DANMARK phone: +45 35321400 direct: +45 35321420 fax: +45 35321401 -- World Wide Web URL: file://ftp.diku.dk/diku/users/kris/WWW/home.html Date: Thu, 10 Mar 1994 23:38:27 +0400 (GMT+4:00) Subject: TLCA: First Call for Papers (Latex) Date: Thu, 10 Mar 1994 13:27:09 +0000 From: Gordon Plotkin \documentstyle{article} \parindent 0cm \pagestyle{empty} \textwidth 18cm \textheight 28cm \topmargin -2.5cm \oddsidemargin -1.2cm \evensidemargin 0cm \begin{document} \begin{center} {\LARGE First Call for Papers} \end{center} \smallskip \begin{center} {\Huge Second International Conference on} \end{center} \begin{center} {\Huge Typed Lambda Calculi and Applications} \end{center} \begin{center} {\Huge TLCA} \end{center} \smallskip \begin{center} {\Large April 10--12, 1995, Edinburgh, Scotland} \end{center} \bigskip The second international conference on Typed Lambda Calculi and Applications will be held April 10--12, 1995, at Edinburgh in Scotland. The conference aims at providing a forum for the presentation and discussion of recent research in the following areas:\vspace{-1cm} \begin{itemize}\begin{center} \item[] \bf Proof theory of type systems \\ \item[] \bf Logic and type systems \\ \item[] \bf Typed lambda calculi as models of (higher order) computation \\ \item[] \bf Semantics of type systems \\ \item[] \bf Proof verification via type systems \\ \item[] \bf Type systems of programming languages \\ \item[] \bf Typed term rewriting systems \end{center} \end{itemize} \bigskip \begin{minipage}[t]{8.5cm} {\large \bf Program} \smallskip The program of TLCA will consist of about 30 selected presentations in plenary sessions. The program committee for TLCA is chaired by M.~Dezani and has the following members: \smallskip {\bf H.~Barendregt}~(Catholic University of Nijmegen) \\ {\bf M.~Dezani}~(Chairperson, University of Turin) \\ {\bf J-Y.~Girard}~(University of Marseilles) \\ {\bf R.~Hindley}~(University of Swansea) \\ {\bf F.~Honsell}~(University of Udine) \\ {\bf J.~W.~Klop}~(CWI) \\ {\bf G.~Longo}~(ENS) \\ {\bf A.~Meyer}~(MIT) \\ {\bf G.~Plotkin}~(University of Edinburgh) \\ {\bf P.~Scott}~(University of Ottawa) \\ {\bf J.~Smith}~(University of Gothenburg/Chalmers) \\ {\bf J.~Tiuryn}~(University of Warsaw) \\ \smallskip {\large \bf Call for Papers} \smallskip Original contributions are solicited for TLCS; they should be sent to the conference secretariat. Electronic submission (PostScript only) is preferred; hard copy (6 copies required) will also be accepted. Papers should be clearly written and allow the program committee to assess the merits of the work. References and comparisons with related work should be included. Papers should not exceed 15 standard pages and should be accompanied by a one-page abstract. The deadline for submissions is September 8, 1994. Authors will receive notification of acceptance by November 12, 1994. Definitive versions of papers will be due December 15, 1994. \end{minipage} \hspace{1cm} \begin{minipage}[t]{8.5cm} {\large \bf Proceedings} \smallskip It is intended to publish the accepted papers as a volume of the Springer Verlag Lecture Notes in Computer Science series.\smallskip\\ {\large \bf Organizing Committee} \smallskip {\bf G.~Cleland, P.~Gardner, M.~Lekuse, G.~Plotkin} \\(University of Edinburgh) \\ {\large \bf Important Dates} \smallskip \vspace{-0.25cm}\begin{tabbing} abcdefghijklmnop\=abcdefghijklmnop\kill Sept. 8, 1994 \>Deadline for submissions \\ Nov. 12, 1994 \>Notification of acceptance \\ Dec. 15, 1994 \>Final version of paper \\ April 10, 1995 \>TLCA \end{tabbing} \vspace{0.1cm}\smallskip {\large \bf TLCA Secretariat} \smallskip TLCA Secretariat \\ Professor M.~Dezani \\ Universit\'{a} di Torino \\ Dipartimento di Informatica \\ Corso Svizzera, 185\\ 10149 Torino \\ ITALY\\ Tel: 39-11-7429232~~Fax: 39-11-751603\\ Email: dezani@di.unito.it \\ {\large \bf $\lambda$-Calculus Network Meeting} \smallskip Participants of TLCA are invited to attend a $\lambda$-Calculus Network Meeting to be held in the weekend before the conference. \end{minipage} \end{document} Date: Thu, 10 Mar 1994 23:35:10 +0400 (GMT+4:00) Subject: Correcting Typos in Lambek-Scott Date: Thu, 10 Mar 94 09:30:45 EST From: SCPSG@acadvm1.uottawa.ca Dear Colleagues: Cambridge University Press is going into the 4th printing of our book "Introduction to Higher Order Categorical Logic" by Jim Lambek and me, and have asked us for any typos (major rewrites are not possible, alas). If anyone knows of typos (there were many in the first printing, due to CUP error, most were corrected by the 3rd paperback) we would appreciate hearing about it. You can write to me (Phil Scott) at the address below. Thanks in advance, Phil Scott scpsg@acadvm1.uottawa.ca Date: Thu, 10 Mar 1994 23:42:23 +0400 (GMT+4:00) Subject: TLCA: First Call for Papers (Plain Text) Date: Thu, 10 Mar 1994 13:27:13 +0000 From: Gordon Plotkin First Call for Papers, TLCA International Conference on Typed Lambda Calculi and Applications April 10--12, 1995, Edinburgh, Scotland The second international conference on Typed Lambda Calculi and Applications will be held April 10--12, 1995, at Edinburgh in Scotland. The conference aims at providing a forum for the presentation and discussion of recent research in the following areas: Proof theory of type systems Logic and type systems Typed lambda calculi as models of (higher order) computation Semantics of type systems Proof verification via type systems Type systems of programming languages Typed term rewriting systems The program of TLCA will consist of about 30 selected presentations in plenary sessions. The program committee for TLCA is chaired by M. Dezani and has the following members: H. Barendregt (Catholic University of Nijmegen) M. Dezani (Chairperson, University of Turin) J-Y. Girard (University of Marseilles) R. Hindley (University of Swansea) F. Honsell (University of Udine) J. W. Klop (CWI) G. Longo (ENS) A. Meyer (MIT) G. Plotkin (University of Edinburgh) P. Scott (University of Ottawa) J. Smith (University of Gothenburg/Chalmers) J. Tiuryn (University of Warsaw) Call for Papers Original contributions are solicited for TLCS; they should be sent to the conference secretariat. Electronic submission (PostScript only) is preferred; hard copy (6 copies required) will also be accepted. Papers should be clearly written and allow the program committee to assess the merits of the work. References and comparisons with related work should be included. Papers should not exceed 15 standard pages and should be accompanied by a one-page abstract. The deadline for submissions is September 8, 1994. Authors will receive notification of acceptance by November 12, 1994. Definitive versions of papers will be due December 15, 1994. Proceedings It is intended to publish the accepted papers as a volume of the Springer Verlag Lecture Notes in Computer Science series. Organizing Committee G. Cleland, P. Gardner, M. Lekuse, G. Plotkin (University of Edinburgh) Important Dates Sept. 8, 1994 Deadline for submissions Nov. 12, 1994 Notification of acceptance Dec. 15, 1994 Final version of paper April 10, 1995 TLCA TLCA Secretariat TLCA Secretariat Professor M. Dezani Universita di Torino Dipartimento di Informatica Corso Svizzera, 185 10149 Torino ITALY Tel: 39-11-7429232 Fax: 39-11-751603 Email: dezani@di.unito.it Lambda-Calculus Network Meeting Participants of TLCA are welcome to attend a Lambda-Calculus Network Meeting to be held immediately before the conference. Date: Fri, 11 Mar 1994 09:33:16 +0400 (GMT+4:00) Subject: term rewriting and sesqui-categories Date: Fri, 11 Mar 1994 11:18:20 +0000 (GMT) From: "John G. Stell" The following paper is available by anonymous ftp. MODELLING TERM-REWRITING SYSTEMS BY SESQUI-CATEGORIES. Abstract It is well-known that a term rewriting system gives rise to a 2-category in which the objects are finite sets of variables, the morphisms are substitutions, and the 2-cells are rewrites. This paper demonstrates that a generalization of a 2-category, called a sesqui-category, is a more appropriate categorical model for a term rewriting system. This is principally because, unlike the case of a 2-category, the sesqui-category associated to a term rewriting system supports a notion of length on its 2-cells. This notion of length is used in developing definitions of local confluence and critical pair in the context of an arbitrary sesqui-category with length and certain additional structure. The relationship between these abstract definitions and their usual term rewriting counterparts is established. This provides some evidence that sesqui-categories may be an appropriate vehicle for an abstract theory of rewriting capable of handling critical pairs. The paper can be obtained by anonymous ftp from ftp.cs.keele.ac.uk the file is pub/techreports/1994/tr94-02.ps ------------------------------------------------------------------------- John Stell Department of Computer Science email john@cs.keele.ac.uk Keele University Keele, Staffordshire, telephone +44 782 583260 ST5 5BG fax +44 782 713082 U. K. ------------------------------------------------------------------------- Date: Sat, 12 Mar 1994 18:06:40 +0400 (GMT+4:00) Subject: T. Wilson's query of Feb 2 Date: Fri, 11 Mar 1994 16:37:45 -0500 (EST) From: MTHISBEL@ubvms.cc.buffalo.edu ... Mr. Wilson has asked a question which was answered on page 14 of vol. 31 of Mathematica Scandinavica (1972) (after the diagram). No. John Isbell Date: Sat, 12 Mar 1994 18:12:08 +0400 (GMT+4:00) Subject: Is Lawvere-Tierney complete? Date: Sat, 12 Mar 1994 13:43:37 +0100 From: Todd Wilson Has anyone proved that the elementary topos axioms are complete for the first-order properties (in the language of categories) of Grothendieck toposes? --Todd Wilson Date: Sat, 12 Mar 1994 23:36:40 +0400 (GMT+4:00) Subject: Re: Is Lawvere-Tierney complete? Date: Sat, 12 Mar 94 18:21:19 EST From: Peter Freyd The first-order properties of a Grothendieck topos include all of first-order arithmetic, hence there can not be a complete axiomization. Date: Sun, 13 Mar 1994 11:31:59 +0400 (GMT+4:00) Subject: mail aliases Date: March 12, 1994 From: Bob Rosebrugh Mike Barr has mentioned that a large mail alias list is maintained on the triples machine at McGill, and that anyone is free to use it. For example, I can be reached by sending mail to rosebrugh@triples.math.mcgill.ca The triples list contains several hundred names of interest to readers of categories. Like Vaughan Pratt's structures directory, the triples list uses surnames, with single initials where necessary as in asmith, bsmith. Date: Tue, 15 Mar 1994 21:40:01 +0400 (GMT+4:00) Subject: PSSL: 2nd announcement Date: Tue, 15 Mar 1994 12:33:58 +0000 (GMT) From: Edmund Robinson SECOND ANNOUNCEMENT 54TH PSSL As previously announced, the 54th meeting of the Peripatetic Seminar on Sheaves and Logic will be held over the weekend of the 26th-27th March 1994 at the University of Sussex. As usual, we welcome talks on topics in logic, category theory and related areas. The meeting will be held in Stage I of the Maths and Physics Building, in lecture theatre PB1A6, starting at 9.30 on the Saturday morning. On the Friday evening, from 7.30 to about 10.00 there will be a gathering in the COGS common room in Stage II of the Maths and Physics Building, at which the program for the meeting will be finalised. Light refreshments will be available. Information about travel, local accommodation, participants and talks offered has been placed in the Sussex anonymous ftp archive (ftp.cogs.sussex.ac.uk, subdirectory pub/pssl) and will continue to be updated as necessary. There is also a mailbox pssl@cogs.sussex.ac.uk, specifically for conference mail. If you have problems with arranging travel or accommodation, please feel free to contact us (please note that we have not arranged accommodation for participants, unless specifically requested). We look forward to seeing you in Sussex. The local organizers, Carolyn Brown, Chris Mulvey, Edmund Robinson, Gavin Wraith Date: Wed, 16 Mar 1994 17:16:32 +0400 (GMT+4:00) Subject: holomorph Date: Wed, 16 Mar 94 10:42:28 +0100 From: Pierre Ageron Thank you to all people who contributed to the discussion about Cantor- Bernstein. I learnt many interesting things, although what I had I mind was rather the general categorical structure underlying the proof. A similar question could be asked about the "elementary" proof of the following theorem : if there is an injection from A to B, then there is injection from 2A to 2B. Another question. The construction of the holomorph of a group is well-known : Hol(G) = G x Aut(G) . Similar constructions can be done for graphs, categories, sketches, ... Has anyone seen anything about that ? Pierre Ageron Date: Thu, 17 Mar 1994 11:48:53 +0400 (GMT+4:00) Subject: holomorph Date: Thu, 17 Mar 1994 08:37:35 +0000 From: "Prof R. Brown" In reply to Pierre Ageron's question: A nice way to regard the holomorph is as follows. The category (groups) is embedded in the category Gd=(groupoids), which is cartesian closed. So Gd has an internal endomorphism and also automorphism object AUT(-) (the maximal internal subgroup object of END(-)). So if G is a group, then AUT(G) is a group-groupoid, also known as a cat^1-group. As a group it is isomorphic to the holomorph of G. (See for example, J Shrimpton, JPAA 72 (1991) 303-318 for background.) Under the correspondence between group-groupoids and crossed modules, the holomorph of G corresponds to the crossed module G--> Aut(G) given by the inner automorphism map. Shrimpton gets an analogous crossed module Q(\Gamma) --> Aut(\Gamma) when \Gamma is a directed graph, and this has an associated group-groupoid, which can be called the holomorph of \Gamma. So the holomorph should be regarded as simply the internal automorphism object (in the appropriate category). If the objects don't form a cartesian closed category to start with, then something must be done about it (like turning groups into groupoids). Maybe you can only form a monoidal closed category. Then you have problems with group objects. See Brown and Gilbert Proc London Math Soc (3) 59 (1989) 51-73 for an example of what can be done (in this case with the category of crossed modules, where the cartesian closed structure is not the really interesting one). The area is interesting, in view of the widespread use of groups in maths and science. What are and what should be "groups"? If S is a structure, how can and should Aut(S) be structured? Ronnie Brown Prof R. Brown Tel: +44 248 382474 School of Mathematics Fax: +44 248 355881 Dean St email: mas010@uk.ac.bangor University of Wales Bangor Gwynedd LL57 1UT UK Date: Sat, 19 Mar 1994 16:17:52 +0400 (GMT+4:00) Subject: Typing and CC Date: Fri, 18 Mar 1994 15:30:29 +0100 (MET) From: Clemens Cap I have two questions, which I hope, someone has the answer or a pointer where I could obtain some hints: Question 1: Let C be a CCC, which not necessarily is a free CCC. Is there a reasonable way of typing C ? More precisely: If X is an object in a (not necessarily free) Cartesian closed category, is it possible to tell, whether X is of the form Y => Z or of the form Y x Z, with suitably chosen Y and Z ? The problem I have is the following: Assume D is a free CCC constructed over a set of constants. Now identify some of the objects in D to yield the not-free CCC C. Now we could think of a situation, where an object in C is of the form U x V and at the same time of the form W => R. On the other hand, the restrictions on the identifications of D-objects, which come from the requirement, that C again is a CCC, could prevent that an object in C could have two possible forms. Question 2: What about the same problem in a symmetric monoidal closed category ? Here things are a bit more complicated, since the bifunctor x no longer is a product and there are no decomposing projection morphisms. In fact, an object which has the form A x (B x C) could be indistingusihable or even identical to an object of the form (A x B) x C. What is known here ? Can an object at the same time be of the form U x V and of the form W => x ?? And what about identifications of products due to assoviativity commutativity and neutrality ? Please reply to cap@ifi.unizh.ch. THANX A LOT FOR YOUR HELP. -- * Prof. Clemens H. CAP cap@ifi.unizh.ch (email) * Dept. of Computer Science +41-1-257 / 4326, 4331 (office voice) * University of Zurich +41-1-363 00 35 (office fax) * Winterthurerstr. 190 +41-1-362 97 11 (home; voice and fax) * CH-8057 Zurich, Switzerland * Motto: "Please do not read the last line of this signature". Date: Sun, 20 Mar 1994 16:38:02 +0400 (GMT+4:00) Subject: Re: Typing and CC Date: Sat, 19 Mar 94 21:36:37 -0800 From: "John C. Mitchell" Can an object at the same time be of the form U x V and of the form W => x ?? Yes, since it is possible for these to have the same cardinality (e.g., cpo's). John Mitchell Date: Sun, 20 Mar 1994 16:35:51 +0400 (GMT+4:00) Subject: question of Clemens Cap Date: Sat, 19 Mar 94 16:20:21 EST From: Michael Barr A propos question 1, there is always the example of a Scott monoid which is a CCC with one object D such that (necessarily) D = D x D = D ==> D. Ok, it is not quite a CCC, since it lacks an empty product, but add one so you have two objects 1 and D with the above properties. This answers question 2 too, but in addition, Beck showed over 20 years ago that any monoidal category with a coherent associativity isomorphism is equivalent, as a monoidal category, to a strictly associative one. Michael Barr Date: Mon, 21 Mar 1994 10:37:16 +0400 (GMT+4:00) Subject: Re: Typing and CC Date: Mon, 21 Mar 1994 12:08:57 +0000 (GMT) From: Edmund Robinson Dear Prof Cap, I just wanted to reinforce the replies of Mitchell and Barr. In any Heyting algebra (cartesian closed poset) there is a great deal of redundancy. In particular, 1 x U = U = 1 => U. And in Set, 0 x U = 0 = V => 0 for any non-empty V, since the empty-set is unique. These are cartesian-closed, and hence a fortiori, monoidal closed, but they are rather semantic models. If you are thinking of presentations of categories as cartesian closed/ symmetric monoidal closed subject to certain equations, then I do not know of any work on syntactic criteria for the equations which would prevent the kind of identification you ask about. This is because a category theorist would never write an equation between objects. Instead they would introduce two maps between the objects (often one at least is pre-existing) and specify that they are inverse isomorphisms. This is not only more in line with "the spirit of category theory", but actually gives you more information, since it tells you how the two structures on the objects are related. In your case, it would tell you, for example, just how a function could be looked at as an ordered pair. A simple equality of objects will not do this. best wishes Edmund Robinson Date: Wed, 23 Mar 1994 15:37:53 +0400 (GMT+4:00) Subject: oriented homology Date: Wed, 23 Mar 94 13:28:30 EST From: Michael Barr It is clear that the symmetric group on n + 1 letters acts on the nth singular chain group by permuting the arguments of a simplex. Suppose we divide out that action by identifying p(sigma) with sgn(p).sigma for each permutation p. This gives a quotient of the singular chain complex. Is it known if it is equivalent to it? The standard argument in the simplicial case seems to break down because two simplexes can have the same vertices without being the same. Michael Barr Date: Wed, 23 Mar 1994 16:35:26 +0400 (GMT+4:00) Subject: corrections to ctcs Date: Wed, 23 Mar 94 15:16:13 EST From: Michael Barr There is going to be a new edition of CTCS (hooray!!) that incorporates all known errata. So if any of you has a list of errors, now is the time to let us know. Please compare against the list that appears in my ftp directory on this computer under the name ctcsupd.tex before sending to us. It will a soft cover edition and may not include the solutions since it is intended as a student edition. Although it seems there will be some hard cover copies bound too. Michael Barr Date: Thu, 24 Mar 1994 14:41:57 +0400 (GMT+4:00) Subject: Re: oriented homology Date: Wed, 23 Mar 1994 17:40:13 -0500 From: James Stasheff seems to me that problem has a history maybe Mac Lane would know?? jim Date: Thu, 24 Mar 1994 15:50:32 +0400 (GMT+4:00) Subject: TEMPUS summer school The following announcement from the Theory Net looked relevant, Bob Rosebrugh Date: Wed, 23 Mar 1994 12:34:55 PST From: Pippo Scollo First Announcement We are pleased to announce a summer school concentrating on ALGEBRAIC LOGIC AND THE METHODOLOGY OF APPLYING IT, July 11-17, 1994, Budapest, which is part of the TEMPUS Summer School series for Algebraic And Categorial Methods In Computer Science. This will be the third one in the above mentioned series of summer schools, attached to the TEMPUS project entitled "Algebraic and Categorial Methods in Computer Science". The summer school is sponsored by the European Community TEMPUS office. Planned courses include: Willem BLOK and Don PIGOZZI: General Algebraic Logic Vaughan PRATT: Chu Spaces: Theory and Applications Yde VENEMA: Boolean Algebras with Operators Istvan NEMETI and Hajnal ANDREKA: Algebras of Relations of Various Ranks & their Applications Decidability issues and logics related to the dynamic trend (workshop given by young researchers). (For the time being, Yde Venema accepted our invitation only tentatively.) We plan to have classes from 10-12 in the mornings and 14-17 in the afternoons from Monday to Friday and 10-12 on Saturday. ACCOMMODATION: In double bedrooms in Summer Hotel Hill, for 14 DM/day. The lectures will be in the same building. 25m swimming pool and several other sport facilities will be available. MEALS: Continental breakfast is available for 4 DM/day. Lunch is available for 5,3 DM/day. SOCIAL PROGRAMS: We plan a reception on Monday evening and a sight seeing afternoon on Wednesday. FEES: The registration fee is 120 DM. REGISTRATION: Please send name, address (including e-mail, if available) and gender to the organizing office by April 30, 1994 at the latest, but send it as soon as you can. Please indicate if you plan to bring a guest or indicate the name of participant with whom you wish to share accommodation. Also indicate if you have any special request (e.g. vegetarian meals). The second circular will be sent only to those who have answered the first circular. The number of participants is limited to 100 persons, therefore registrations will be accepted in the order of receipt. SCHOLARSHIPS: This year, unfortunately, the TEMPUS JEP is not allowed to give any grant to students from EC countries for participation at the summer school. All that they can offer is a grant for 1 professor from each of the partner universities. Grants for students from eastern partner universities are available in a limited number. Please, apply for them to the organizing committee. ORGANIZING COMMITTEE: Hajnal Andreka, Miklos Ferenczy, Istvan Nemeti and Ildiko Sain ORGANIZING SECRETARY: Corinna Farkas. ADDRESSES: Please send your correspondence to BOTH of the following two e-mail addresses: cora@ludens.elte.hu and h1468sai@ella.hu, or to the following mailing address: Ildiko Sain Mathematical Institute Hung. Acad. Sci. Budapest Pf. 127 H-1364 Hungary Fax: (36-1) 117-7166 (indicate: To Ildiko Sain) PLEASE, DISTRIBUTE THIS ANNOUNCEMENT FREELY. Hoping to hear from you, Best regards from the organizers. Date: Fri, 25 Mar 1994 16:08:11 +0400 (GMT+4:00) Subject: Reference wanted : Joyal, combinatorial functors Date: Fri, 25 Mar 94 08:23:33 +0800 From: Michael FOURMAN Greetings! Apologies for broadcasting this, but I'm a bit isolated (visiting here until June) and need a reference. Can anyone supply a full reference for Andre Joyal's monograph on combinatorial functors? Many thanks, Mike Fourman Date: Fri, 25 Mar 1994 16:10:10 +0400 (GMT+4:00) Subject: Math Report Hardcopies Date: Fri, 25 Mar 1994 13:35:15 +1000 From: Ross Street About 60 hardcopies of a 33 page preprint entitled "The category of representations of the general linear groups over a finite field" by Andre Joyal and myself has just come back from the Macquarie University printer. It is Macquarie Math Report # 93-141 (Dec 1993); a full treatment of the subject of Section 4 of our paper "Braided tensor categories" Advances in Math 102 (1993) 20-78. Since this is a categorical treatment of a fairly specialized topic, I do not intend to conduct a general mailing of the Report. However, if you would like a copy, I'll send one if you email me at and provide your precise postal address. I believe Andre is having some hardcopies made at UQAM. [The paper is stored in computers at UQAM & Macquarie and can be sent via email, but requires my kinky software to decode.] --Ross Street Date: Thu, 31 Mar 1994 13:24:50 +0400 (GMT+4:00) Subject: Michael Spivak Date: Wed, 30 Mar 94 16:16:37 EST From: Elaine Swan Can anyone supply me with an email address for Michael Spivak or the publishing company -- Publish or Perish Press? Thank you in advance Date: Thu, 31 Mar 1994 14:51:29 +0400 (GMT+4:00) Subject: local homeomorphisms Date: Thu, 31 Mar 94 13:08:53 EST From: Peter Freyd Peter Selinger, a student here at Penn, observes that the category of topological spaces and local homeomorphisms fails to be complete only because it fails to have a terminator. That is, every _non-empty_ small diagram has a limit. Who knows a reference for this? Peter Freyd Date: Thu, 31 Mar 1994 21:45:17 +0400 (GMT+4:00) Subject: Second Announcement Date: 31 Mar 94 14:17:00 EST From: "NIEFIELD, SUSAN " SECOND ANNOUNCEMENT UNION COLLEGE MATHEMATICS CONFERENCE April 9-10, 1994 Please reply to this message, if you plan to attend and have not yet contacted us. FRIDAY EVENING RECEPTION: 9:00 - 11:00 PM (Bailey Hall 204) SATURDAY 9:30 Registration, coffee, doughnuts (Bailey 204) 10:00 Parallel Sessions (Bailey Second Floor) 11:30 Invited Address I: Andre Joyal (Bailey 207) 12:30 Lunch (The College Center) 2:00 Parallel Sessions (Bailey Second Floor) 4:00 Coffee Break (Bailey 204) 4:30 Invited Address II: Peter May (Bailey 207) 5:30 Cocktails (Hale House Lower Lounge) 6:30 Banquet (Hale House Dining Room) 8:00 Dessert and Party (Milano Lounge) SUNDAY (Bailey Hall 2nd Floor) 9:00 Coffee and doughnuts (Bailey 204) 9:30 Invited Address III: Zoltan Balogh (Bailey 207) 10:30 Parallel Sessions (Bailey Second Floor) 12:00 Lunch (The College Center) 1:00 Parallel Sessions (Bailey Second Floor) 3:30 Conference ends CATEGORY THEORY SPEAKERS: A. Joyal, University of Quebec at Montreal "Money games" M. Barr, McGill University "Acyclic models" R. Blute, University of Ottawa "Linear Lauchli semantics" M. Bunge, McGill University "A characterization of Grothendieck toposes in Set-Modules" P. Glenn, Catholic University of America "Structures with a simplicially-defined higher dimensional composition" M. Kleiner, Syracuse University "Green correspondence for adjoint functors" J. Lambek, McGill University "Diagram chasing in Goursat categories" H. Hu, York University "Limits in free coproduct completions" M. Mannucci, CUNY "Modal geometric theories and their semantics" W. Tholen, York University "Locally split epis and effective descent" ALGEBRAIC TOPOLOGY SPEAKERS: J.P. May, University of Chicago "Derived Categories in Algebra and Topology" S. Costenoble, Hofstra University "Some strange facts about ordinary equivariant homology" T. Elmendorf, Perdue University Calumet "Remarks on the Cyclotomic Structure of THH" R. McCarthy, Brown University "The Calculus of Homotopy Functors and Algebraic K-Theory" R. Singer, Fordham University "Just how much does one require to induce a map of Tor?" SET-THEORETIC TOPOLOGY SPEAKERS: Z. Balogh, Miami University of Ohio "A solution to the small Dowker space problem" T. LaBerge, Union College "Forcing tightness in products of fans" S. Hechler, Queens College TBA A. Zarach, East Stroudsburg University "A model for ZF without power set" ACCOMMODATIONS: Blocks of rooms have been reserved at the Days Inn and the Holiday Inn in Schenectady. To obtain one of these rooms at the rates listed below, mention the Union College Mathematics Department when you call. Both are within easy walking distance of the campus. The Ramada Inn is also within walking distance of campus. 1. Holiday Inn (518) 393-4141 Single $55 Double $55 2. Days Inn (518) 370-0851 Single $45 Double $50 3. Ramada Inn (518) 370-7151 Single $63 Double $73 DIRECTIONS: >From points South and East, take the New York Thruway to exit 25. Take I-890 to exit 7 (marked "NY 7 east to Troy"). Follow Route 7, turn left onto Balltown Road (marked "to 146"), and then turn left at the first traffic light onto Union Street. Follow Union Street and enter campus through Payne Gate on the right. Bailey Hall is on the east side of campus, just west of the athletic field. >From points West, take the New York Thruway to exit 26, then I-890 to Erie Boulevard (exit 4). Follow Erie Boulevard to Union Street, turn right onto Union Street, and enter campus through Payne Gate on the left. Bailey Hall is on the east side of campus, just west of the athletic field. >From points North, take the Northway (I-87) to exit 9 (marked "146 Clifton Park"). Turn right, follow 146 for about 6 miles to a traffic light, and turn left onto Balltown Road (still 146). Follow Balltown Road over the Mohawk River. Turn right onto Aqueduct Road (which becomes Van Vranken Avenue when it enters Schenectady) and continue until it ends at the Union College campus Nott Street gate. Bailey Hall is on the east side of campus, just west of the athletic field. Union College Department of Mathematics Schenectady, NY 12308 (518) 388-6246