July 1998 - Categories - categories.org.au

Lectureships at Queen Mary and Westfield
by Edmund Robinson 31 Jul '98

31 Jul '98

Please accept my apologies if (more accurately when) you receive multiple copies of this message. Since it is summer, please also consider informal discussions with me as acting Head of Department (edmundr(a)dcs.qmw.ac.uk) best wishes Edmund Robinson ------------------------------------------------------- Queen Mary and Westfield College, London, UK Lecturer(s) in Computer Science Following recent successful appointments the Department of Computer Science is seeking further Lecturers. The Department is consolidating its research strength and seeking to appoint strong researchers in the areas of Distributed Systems, Human Computer Interaction, Computer Vision or Programming Languages and Theoretical Computer Science. Applicants with research interests in mobile computing, multimedia and CSCW are encouraged. At least one of the posts will be targeted at the areas of Distributed Systems or Human Computer Interaction. Candidates should be able to teach a range of undergraduate and postgraduate Computer Science courses. Salary according to experience range from Lecturer A/B UKP 18,500 to UKP 30,679 p.a. inclusive, rising to UKP 18,789 - UKP 31,182 (UK pounds) from 1 October 98. Informal enquiries may be made to Professor Heather Liddell (Head of Department) on 0171 975 5167 - email: heather(a)dcs.qmw.ac.uk or Professor Peter Johnson on 0171 975 5224 - email: pete(a)dcs.qmw.ac.uk. Further details of the Department, its research activity, and the expected role of the appointees are available on-line. For a printed copy of these details and an application form please telephone our 24 hour Recruitment Line on 0171 975 5171 or Email: coll-recruit(a)qmw.ac.uk quoting Reference 98125LC. Completed application forms should be returned by 18th August 1998 to the Personnel Office, Queen Mary and Westfield College, London E1 4NS.

1 0

Visiting Position
by Klaus Keimel 26 Jul '98

26 Jul '98

Visiting Lecturer/Professor in Computer Science There is a Visiting Lectureship/Professorship available at the University of Technology at Darmstadt for a period of either six months or one year starting on October 1, 1998. (There is an unexpected vacancy that occurred just yesterday.) In October we are starting a new curriculum 'Mathematics with Computer Science' with an international orientation. In the first year, courses are taught in English. There will be German and international students. The visiting Lecturer/Professor is expected to teach the first year course of Computer Science in ENGLISH within this framework. The remuneration will be according to the German system depending on qualification and age. If you are interested, please contact Prof. Dr. Klaus Keimel Fachbereich Mathematik Technische Universitaet D-64289 Darmstadt, Germany Tel. + 49 6151 162215 Fax. + 49 6151 164011 e-mail: keimel(a)mathematik.tu-darmstadt.de Please pass this announcement to any person that could be interested. More information about the new course: http://www.mathematik.tu-darmstadt.de/dekan/MCS/mcs-detailed.html

1 0

FM'99 World Congress on Formal methods, 20-24 Sept. 1999, Toulouse, France
by Dines Bjorner 22 Jul '98

22 Jul '98

Dear Colleague, ACM, AMAST, ASM, EATCS, ETAPS, EU, FME, IFIP, IEEE CS, IPSJ, JSSST are co-sponsoring and FME is organising: FM'99: World Congress on Formal Methods (in the development of computing systems) 20-24 Sept. 1999, Intl.Congress Ctr., Toulouse, France You may wish to inspect: FM'99 Main http://www.it.dtu.dk/~db/fm99/FM99Main/FM99Main.html and/or FM'99 Congress http://www.it.dtu.dk/~db/fm99/FM99Congress/FM99Congress.html from where documents on separate Congress events can be accessed: Technical Symposium http://www.it.dtu.dk/~db/fm99/FM99Symposium/FM99Symposium.html including: Mini-Tracks http://www.it.dtu.dk/~db/fm99/FM99Minis/FM99Minis.html Tools Fair & Applications Forum http://www.it.dtu.dk/~db/fm99/FM99Tools/FM99Tools.html Users and Working Group Meetings http://www.it.dtu.dk/~db/fm99/FM99UsersGroups/FM99UsersGroups.html FM'99 Industry Tutorials http://www.it.dtu.dk/~db/fm99/FM99Tutorials/FM99Tutorials.html Sincerely Dines Bjorner General Chair

1 0

preprint available
by JONATHON FUNK 22 Jul '98

22 Jul '98

Dear Colleagues, A preprint, whose abstract follows, is available in compressed .dvi form (for DOS and for UNIX) from: http://www.emu.edu.tr/academic/facartsc/mathsdep/staffpic/jfunk.htm or if you are browsing the web, click on academics, teaching staff, Mathematics, Jonathon Funk, additional information, after you have reached the EMU homepage http://www.emu.edu.tr If you would like a copy, but are unable to retrieve the preprint, please don't hestitate to contact me, as I would be happy to send you the .dvi file personally. funk(a)mozart.emu.edu.tr ---------------------------------------------------------------- ``On branched covers in topos theory'' Abstract: We present some new findings conerning branched covers in topos theory. Our discussion involves a particular subtopos of a given topos that can be described as the smallest subtopos closed under small coproducts in the including topos. We also have some new results concerning the general theory of KZ-doctrines, such as the the closure under composition of discrete fibrations for a KZ- doctrine (in the sense of Bunge/Funk, ``On a bicomma object condition for KZ-doctrines''). Regards, Jonathon Funk Jonathon Funk Department of Mathematics Eastern Mediterranean University Gazimagusa Turkish Republic of North Cyprus via Mersin 10, Turkey tel: (90) 392 366 6588, Ext: 1227, 1228, 1138 fax: (90) 392 366 1604

2 3

java Workshop Reminder
by Susan Eisenbach 22 Jul '98

22 Jul '98

About two months ago I announced a workshop on formal underpinnings of Java. Since then I've had email from Java Software at Sun (what used to be called Javasoft) expressing interest. They said: Our main interest is in formal specification of Java byte code verification because that is an area where a formal spec is both realistic and sorely needed. We hope to be able to adapt some approach developed in the research community. If you are doing work in this or related work there is still time to submit an extended abstract to our workshop. Formal Underpinnings of Java - an OOPSLA'98 Workshop Important Dates Submissions: 31 July 1998 Notifications: 20 August 1998 Final Versions: 20 September 1998 Workshop: Sunday, 18 October 1998, Vancouver, Canada Java offers a novel paradigm for program deployment. It supports intermediate code that is dynamically loaded from remote sites - sometimes without the user's knowledge. For Web pages, Java applets can greatly improve interactivity; for Java developers, the Java paradigm promises benefits in portability and manageability. However, the Java paradigm also opens new possibilities for abuse and has caused concern about security. The application of formal methods to the Java paradigm aims to provide a better understanding of the approach by rigorously formulating and trying to prove the soundness of binary compatibility, type safety, security and other guarantees made by Java. It also aims to provide some guidance for further development of the paradigm by uncovering possible design flaws and by supplying a platform for the description of future extensions. This workshop aims to bring together researchers to share new ideas and results. Since the main focus in selecting workshop contributions will be the intrinsic interest and timeliness of the work, authors are encouraged to submit (polished) descriptions of work in progress as well as papers describing completed projects. The proceedings will be published as a Princeton University technical report and be available from the web. We solicit submissions on original research on the following, or related subjects: semantics of Java semantics of byte code, correctness of the byte code verifier formal verification of Java programs separate compilation, binary compatibility dynamic linking and loading security policy practicality of formal methods for Java comparison of approaches, tools Electronic versions of extended abstracts between 2500 and5000 words (approximately 5-10 pages) should be e-mailed to S.Eisenbach(a)doc.ic.ac.uk by Friday, 31 July 1998, using US-letter or A4 size,Postscript or PDF. The submission may be included inline in the message or as a MIME attachment only. (If electronic submission is impossible, postal submissions must be received by Friday 31 July 1998; enclose 4 double-sided copies, a return postal address, a phone number, and a return e-mail address.) Receipt of the submissions will be acknowledged by e-mail. The authors should inquire in case a prompt acknowledgment is not received. Program Committee Susan Eisenbach, Imperial College Jim Alves-Foss, University of Idaho Drew Dean, Princeton University Sophia Drossopoulou, Imperial College Tobias Nipkow, Technische UniversitÃ¤t MÃ¼nchen Raymie Stata, Digital Equipment Corporation Correspondence and questions should be sent to S.Eisenbach(a)doc.ic.ac.uk http://www-dse.doc.ic.ac.uk/~sue/oopsla/cfp.html

1 0

Answers
by Michael Barr 21 Jul '98

21 Jul '98

I got the same counter-example from Peter Johnstone and Peter Freyd. PJ called it the dunce cap and described it as a triangle with the three edges identified, one in the reverse direction. PF described it in a more complicated way that made it easier to see it actually contractible. And the latter was really what I wanted to refute. When I saw PJ's example, I mistakenly thought it still had a 1-cycle. The smallest triangulation I found had 8 vertices, which is still too large to compute by hand with. The dual complex still has over 200 simplexes and that is just too many. If anyone knows a smaller triangulation, I would like to know it. Thanks to all who responded. Michael

1 0

Alfred Sober - some recollections
by s.vickers＠doc.ic.ac.uk 21 Jul '98

21 Jul '98

Recent mention of sober spaces brought to mind memories of Alfred Philpott Sober, whose sad death from liver failure five years ago ended a long career in topology. Though largely unpublished, it was his work that underlay the notion of what are now known as sober spaces. In Sober's view, points of topological spaces are essentially blurred and hazy: however hard you try to focus on them they always seem to jiggle about a bit - to him "focusing on a point" meant to find it within some _open_ neighbourhood, and these almost always left some room for manoeuvre. He understood the points to be exactly their open neighbourhood filters, and the spaces that would now be called non-sober were trying to impose an over-clear view of reality, making artificial distinctions between what was actually the same thing or trying to deny the existence of something he could see with his own eyes. On the related subject of continuity, he saw its essence as that of a function was that was not unduly upset by this jiggling: as long as the argument didn't jiggle too much, the result wouldn't either, and he liked to demonstrate the idea by carrying a tray of drinks across a crowded room. Though not one of the founders of locale theory, he was aware of the idea and greatly sympathetic to it - though he couldn't see any reason for using the French spelling and pronunciation. Once when in the midst of explaining his ideas the lattice structures started to become manifest and he would excitedly talk about "getting down to the local". He studied initially at Cambridge under the influence of Charles Wells (the Bedford Charles Wells, NOT the well-known category theorist) and his thesis, starting off on Klein bottles, soon took in Gross bottles too. He made his academic home in the University of Portsmouth and was much loved by both his colleagues and his students for his parties and for his never-failing warm welcome "Come in and what'll you have?" He is much missed by all who knew him. Steve Vickers.

1 0

2 Barr questions
by Peter Freyd 20 Jul '98

20 Jul '98

I've got well over a thousand e-mails waiting to be looked at. I'm working on the pile from both ends. Two recent postings from Mike Barr: 1) The duality he describes sounds like Spanier-Whitehead duality. It's usually defined geometrically. Embed a finite complex into a higher-dimensional sphere, take the complement, contract it to a finite complex. Do this in the stable-homotopy category (obtained by forcing the suspension functor on the homotopy category to become an automorphism) and normalize the dimensions so that the dual of a space has the negative of its dimension. Show that the embeddings can be chosen in a coherent fashion to obtain a self-duality for stable homotopy. (The last step is non-trivial and the only person I know who verified it is Frank Adams, and that wasn't published. Does anyone have a citation?) 2) If every n-1 cell of an n-dimensional finite complex is the face of _exactly_ 2 n-dimensional cells then there's a fairly easy argument that the n-dimensional Z_2 cohomology is non-trivial. But if the condition is changed to "_at least_ 2 n-dimensional cells" then the space can be contractible. Start with the closed unit disk in the complex plane and glue the boundary onto the closed unit interval (which constitutes half of the intersection of the disk and the real line) by identifying a point x on the interval with e^(2(pi)xi) on the boundary. If one triangulates this space, each edge will be a face of either 2 or 3 triangles. One way of seeing that this is contractible is to consider first the space obtained by identifying just the upper half of the boundary with the unit interval by identifying a point x on the interval with e^((pi)xi) on the boundary. Recalling that the homotopy type of a space is unchanged when reasonable closed contractible subsets are collapsed to points, note that if the lower half of the boundary is collapsed to a point we obtain the first space. On the other hand, the upper half (together with the unit interval) is contractible, and when it's collapsed to a point we obtain the unit disk. By taking the suspension of this example we can get an example in every larger finite dimension. This example is a mapping cone. Take the map from the circle to the circle that wraps the first third of the circle around the circle, wraps the second third around in the opposite direction, and the last third in the original direction. This map is, of course, homotopic to the identity map. The mapping-cone construction depends only on the homotopy type of the map. The mapping cone of the identity map on the circle is, of course, the disk.

1 0

DMTCS99+CATS99 final call
by Paul Bonnington 20 Jul '98

20 Jul '98

FINAL CALL FOR PAPERS (Please Circulate) DMTCS'99, Discrete Mathematics and Theoretical Computer Science and CATS'99, Computing: The Australasian Theory Symposium University of Auckland and CDMTCS, Auckland, New Zealand 18-21 January 1999 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% DMTCS'99 and CATS'99 will be part of the Australsian Computer Science Week (ACSW'99). Original papers are solicited in all areas of discrete mathematics and theoretical computer science. Typical, but not exclusive, topics of interest include: (a) abstract data types and specifications, (b) algorithms and data structures, (c) automata and formal languages, (d) computability and complexity, (e) computational algebra, biology, geometry, logic and number theory, (f) concurrency, distributed systems and parallel computing, (g) constructive mathematics, (h) discrete mathematics, combinatorial computing and category theory, (i) formal semantics, specification, synthesis and verification, (j) hybrid systems and nonmonotonic logic. Authors are invited to submit papers either in hard copy by post, or electronically by email, to the address below. Electronic submissions should be in PostScript format, printable in a standard Unix environment. LaTeX source of final versions of accepted papers will be required. Submissions should not exceed 15 pages and include an e-mail address of the corresponding author. Joint submissions to other conferences are not permitted. At least one author of each accepted paper is expected to register by Nov. 6th and present their work at the conference. The proceedings will be published by Springer-Verlag, Singapore in the DMTCS Series, and will be made available during the conference. Invited Speakers: R. Downey (UVW, NZ) J. Goguen (UCSD, USA) A. Nerode (Cornell, USA) J. Pach (Hungarian Academy of Sciences) A. Restivo (U. Palermo, Italy) G. Walsh (U. Ottawa) Address For Submissions: DMTCS'99+CATS'99 (Attn: Michael Dinneen), Department of Computer Science, University of Auckland, Private Bag 92019, Auckland, New Zealand, Email: mjd(a)cs.auckland.ac.nz Cost of Participation: The registration fee is A $400 (which includes the dinner, excursion and proceedings), or A $100 for students (including only the proceedings). For More Information: See the home-page of the conference http://www.tcs.auckland.ac.nz/~acsw99/, or contact the local chair Bakh Khoussainov at bmk(a)cs.auckland.ac.nz. --------------------------------------------------------------------------- Conference Committee: C.P. Bonnington C.S. Calude (general chair) E. Calude R. Coles, P.B. Gibbons U. Guenther B. Khoussainov (local chair) ACSW'99 Contact Members: R.W. Doran (general chair) P. Fenwick Programme Committee: R.J. Back, TUCS, Finland M. Conder, U. Auckland, NZ B. Cooper, U. Leeds, UK M.J. Dinneen, U. Auckland, NZ (chair) R. Goldblatt, Victoria U., NZ S. Goncharov, Novosibirsk U., Russia J. Harland, RMIT, Australia R.E. Hiromoto, UTSA, USA H. Ishihara, JAIST, Japan M. Ito, Kyoto S.U., Japan M. Li, U. Waterloo, Canada X. Lin, UNSW, Australia R. Shore, Cornell U., USA T. Tokuyama, IBM, Japan D. Wolfram, ANU, Australia Proceedings Editors: C.S. Calude and M.J. Dinneen --------------------------------------------------------------------------- Important Dates: Submissions Due: 31 July 1998 Notification Date: 09 Oct. 1998 Final Copies Due: 30 Oct. 1998 Registration Date (for authors): 06 Nov. 1998 (for others): January 1999 --------------------------------------------------------------------------- %%% DMTCS'99+CATS'99 Call for Papers %%% %%% Disclaimer: The following is very hacked LaTeX. %%% \documentstyle[11pt]{article} \pagestyle{empty} \oddsidemargin=-18.5truept \textwidth=7in %\topmargin=0.12in \topmargin=-0.4in \textheight=9.7in \newcommand{\mylistlabel}{\hspace\labelsep } \newenvironment{mylist}{\begin{list}{\hbox{}}% {\leftmargin 18pt \labelwidth 0pt \itemindent-\leftmargin \itemsep -1pt \let\makelabel\mylistlabel}}% {\end{list}} \newcommand{\fillin}{\typeout{*** Fill in! ***}??} \newcommand{\recheck}[1]{\typeout{*** Recheck This! ***}#1} \begin{document} %%% %%% CDMTCS Logo %%% % % \hbox{}\vspace*{-0.8in}\hfill\makebox[5pt]{\epsffile{ieee-cs.eps}} % %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \vspace*{-1.2in} \begin{center} % \makebox[5pt]{\epsffile{ieee-cs.eps}} \\[3ex] \LARGE\bf Call for Papers\\[2ex] \Large\bf \mbox{DMTCS'99---Discrete Mathematics and Theoretical Computer Science}\\[0pt] \Large and\\[0pt] \Large\bf CATS'99---Computing: The Australasian Theory Symposium\\[3ex] {\large University of Auckland and CDMTCS, Auckland, New Zealand \\[2ex] \large\bf 18-21 January 1999} \end{center} \vspace*{4ex} %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%% %%% Sidebar %%% \begin{minipage}[t]{2.0in}\footnotesize \medskip %\noindent{\bf University of Auckland}\\ \noindent{\bf Conference Committee} \begin{mylist}\raggedright \item C.P. Bonnington % (information) \item C.S. Calude (general chair) \item E. Calude % (venue) \item R. Coles % (records) \item P.B. Gibbons % (accomodation) \item U. Guenther % (registration) \item B. Khoussainov (local chair) \end{mylist} \medskip \noindent{\bf ACSW'99 Contact Members} \begin{mylist}\raggedright \item R.W. Doran (general chair) \item P. Fenwick \end{mylist} \medskip \noindent{\bf Programme Committee} \begin{mylist}\raggedright \item R.J. Back, TUCS, Finland \item M. Conder, U. Auckland, NZ \item B. Cooper, U. Leeds, UK \item M.J. Dinneen, U. Auckland, NZ (chair) \item R. Goldblatt, Victoria U., NZ \item S. Goncharov, Novosibirsk U., Russia \item J. Harland, RMIT, Australia \item R.E. Hiromoto, UTSA, USA \item H. Ishihara, JAIST, Japan \item M. Ito, Kyoto S.U., Japan \item M. Li, U. Waterloo, Canada \item X. Lin, UNSW, Australia \item R. Shore, Cornell U., USA \item T. Tokuyama, IBM, Japan \item D. Wolfram, ANU, Australia \end{mylist} \medskip \noindent{\bf Proceedings Editors} \begin{mylist}\raggedright \item C.S. Calude \item M.J. Dinneen \end{mylist} \medskip\noindent{\bf Important Dates} \begin{mylist}\raggedright\frenchspacing \item \makebox[1.1in][l]{Submissions Due:} \makebox[0.26in][l]{31 July 1998} \item \makebox[1.1in][l]{Notification Date:} \makebox[0.26in][l]{9 Oct. 1998} \item \makebox[1.1in][l]{Final Copies Due:} \makebox[0.26in][l]{30 Oct. 1998} \item \makebox[1.1in][l]{Registration Date} \item \makebox[1.1in][l]{for Authors:} \makebox[0.26in][l]{6 Nov. 1998} \end{mylist} \end{minipage} %%% %%% Vertical Line %%% \hspace*{4.75pt}\rule[-7.7in]{0.5pt}{7.9in}\hspace*{4.75pt} %%% %%% Main Column %%% \begin{minipage}[t]{4.25in} \parskip\smallskipamount DMTCS'99 and CATS'99 will be part of the Australsian Computer Science Week (ACSW'99). Original papers are solicited in {\sl all\/} areas of discrete mathematics and theoretical computer science. Typical, but not exclusive, topics of interest include: (a) abstract data types and specifications, (b) algorithms and data structures, (c) automata and formal languages, (d) computability and complexity, (e) computational algebra, biology, geometry, logic and number theory, (f) concurrency, distributed systems and parallel computing, (g) constructive mathematics, (h) discrete mathematics, combinatorial computing and category theory, (i) formal semantics, specification, synthesis and verification, (j) hybrid systems and nonmonotonic logic. Authors are invited to submit papers either in hard copy by post, or electronically by email, to the address below. Electronic submissions should be in PostScript format, printable in a standard Unix environment. \LaTeX{} source of final versions of accepted papers will be required. Submissions should not exceed 15 pages and include an e-mail address of the corresponding author. Joint submissions to other conferences are {\sl not\/} permitted. At least one author of each accepted paper is expected to register by Nov.~6th and present their work at the conference. The proceedings will be published by Springer-Verlag, Singapore in the DMTCS Series, and will be made available during the conference. \medskip {\bf Invited Speakers:} R.~Downey (UVW, NZ), J.~Goguen (UCSD, USA), A.~Nerode (Cornell, USA), J.~Pach (Hungarian Academy of Sciences) and A.~Restivo (U. Palermo, Italy). \medskip {\bf Address For Submissions:} DMTCS'99+CATS'99 (Attn: Michael Dinneen), Department of Computer Science, University of Auckland, Private Bag 92019, Auckland, New Zealand, {\tt mjd(a)cs.auckland.ac.nz}. \medskip {\bf Cost of Participation:} The registration fee is A\$400 (which includes the dinner, excursion and proceedings), or A\$100 for students (including only the proceedings). \medskip {\bf For More Information:} See the home-page of the conference \verb|http://www.tcs.auckland.ac.nz/~acsw99/|, or contact the local chair Bakh Khoussainov at {\tt bmk(a)cs.auckland.ac.nz}. \end{minipage} \end{document}

1 0

More algebraic topology
by Michael Barr 19 Jul '98

19 Jul '98

I have a real question now. Suppose S is a simplicial complex of dimension n with the property that every n-1 face of every n simplex is a face of at least two n simplexes. I want to conclude that H_n(S) is non-zero. Assume that the union of the n simplexes is connected (any connected component would inherit the hypothesis). Then it seems clear geometrically that the union of the faces would enclose one or more holes, but I don't see how to actually prove this. The space would appear to have no boundary, but it also is not a manifold since a point in one of the faces could have a branched neighborhood.

2 1