Date: Tue, 5 Apr 1994 11:28:25 +0500 (GMT+4:00)
Subject: Re: local homeomorphisms
Date: Tue, 5 Apr 94 08:53:53 EDT
From: Peter Freyd
In my last posting I had written:
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?
What I didn't realize is that he was correcting an error in
"Categories, Allegories." On page 50 (1.461) we wrote that the
category in question fails to have binary products. Wrong.
I'm concluding that this was not known before. It's a nice example of
a product that's very much not preserved by the forgetful functor. The
product of the space of rational numbers with itself is uncountably
large. (And for every infinite cardinal there's a space whose product
with itself has the next power-cardinal as its size.)
Date: Tue, 5 Apr 1994 11:27:34 +0500 (GMT+4:00)
Subject: PSSL
Date: Tue, 5 Apr 94 12:56:14 BST
From: Lorraine Edgar
PERIPATETIC SEMINAR ON SHEAVES AND LOGIC
55th Meeting---Preliminary Announcement
The 55th meeting of the seminar will be held at the University of
Edinburgh's Computer Science Department over the weekend of 28-29
May 1994. As usual, we welcome talks near the triple point
linking category theory, geometry and logic.
We will send further information on the location of the seminar, along
with local travel details, on receipt of registration forms. A list
of guest houses/hotels available from lme@dcs.ed.ac.uk on request. It
is easiest for us if UK participants make their own arrangements for
accommodation, but we will be happy to try and help anyone who has any
difficulties. Edinburgh, as one of the world's prettiest cities, is a
tourist haven in summer, so it would be advisable to secure
accommodation well in advance.
John Power
Marcelo Fiore
Lorraine Edgar
-------------------------------------------------------------------------------
Please return to Lorraine Edgar, Dept of Computer Science, University of
Edinburgh, The King's Buildings, Edinburgh EH9 3JZ.
I intend to come to the 55th meeting of the PSSL.
* I intend to give a talk entitled
* Please reserve accommodation for Friday/Saturday/Sunday night(s).
Name Address
Email Tel No
Fax No
(* Delete if inapplicable)
Date: Wed, 6 Apr 1994 16:11:10 +0500 (GMT+4:00)
Subject: Re: local homeomorphisms
Date: Wed, 6 Apr 1994 13:33:00 -0400 (EDT)
From: D_FELDMAN@UNHH.UNH.EDU
Allow me please to muse on Peter Freyd's two postings concerning observations
of Peter Selinger and himself on the category of topological spaces and local
homeomorphisms.
Is the product of X_1 and X_2 identical to the etale space of the
sheaf that associates to an open set U of X_1 all the local homeomorphisms
from U to X_2? Of course if this is right, then the roles of X_1 and
X_2 can be reversed. Indeed, both etale spaces consist of germs of
homeomorphisms between X_1 and X_2.
The advantage of taking this point of view, besides that fact that perhaps
the sheaf is easier to thing about than its etale space, is that it
suggests persuing a more general construction. In a sense that I don't
yet know how to make precise, X_1 x X_2 is a schizophrenic object because
it lives in both toposes of sheaves, over X_1 and X_2, and it is in some
sense the universal such schizophrenic object. So my question is, can
this be made precise so that one could ask for a universal schizophrenic
given any two toposes. My guess is that the analogous construction
given the topos of M_1-sets and M_2-sets, M_1 and M_2 being monoids,
would be to construct the free product M_1 * M_2, which also lives
naturally in both categories. Moreover all M_1 * M_2-sets live in
both categories, just as all sheaves over X_1 x X_2 induce sheaves over
X_1 and over X_2.
I don't know much about toposes. Is there already some well-known
construction that fits the bill?
David Feldman
University of New Hampshire
Date: Wed, 6 Apr 1994 16:09:43 +0500 (GMT+4:00)
Subject: Re: local homeomorphisms
Date: Wed, 6 Apr 1994 3:21:43 -0400 (EDT)
From: D_FELDMAN@UNHH.UNH.EDU
Would the category of topological spaces and partial local homeomorphisms
be complete? I mean, partial maps which are local homeomorphism on
their locus of definition.
David
Date: Wed, 6 Apr 1994 16:15:05 +0500 (GMT+4:00)
Subject: Workshop on foundational methods in Computer Science
Date: Thu, 31 Mar 94 14:52:15 -0800
From: John MacDonald
Preliminary Announcement:
Third Annual Workshop on
Foundational Methods in Computer Science
A workshop on applications of categories in compouter science
Dates: June 3-5, 1994
Location: University of British Columbia, Vancouver, B. C.
Overview:
This will be the third year of the workshop on foundational methods
in computer science. It is an "informal, even casual", workshop
bringing together mathematicians and computer scientists with an
interest in category theory and its applications to computer science.
The workshop will have approximately the same format as last year,
with a one day tutorial on June 3 and short research presentations on
June 4 and 5. There will not be a formal proceedings.
Guests:
We are still in the process of contacting distinguished visitors and
guests.
Participation:
People wishing to participate should send me email at
fmcs@math.ubc.ca. We hope to encourage the participation of
researchers at all levels in this workshop, including graduate
students.
Fees:
I have made arrangements for accomodations on the UBC campus. The
budget has not been completed so I don't yet have a registration
fee calculated. I hope to keep the fees to an absolute minimum.
An application for dormitory accomodation as well as the amount of
registration fee will come in a further communication.
Email address: fmcs@math.ubc.ca
--------------------------------------------------------------------
John MacDonald, Department of Mathematics, UBC, Vancouver, B.C.,
Canada V6T 1Y4
johnm@math.ubc.ca
Phone: (604) 822-3627
---------------------------------------------------------------------
Art Stone
stone@math.ubc.ca
Phone: (604) 421-3054
Date: Wed, 6 Apr 1994 21:57:30 +0500 (GMT+4:00)
Subject: LICS'94 Program and Registration
Date: Wed, 6 Apr 94 19:41 EDT
From: Amy Felty
[This announcement is being sent to email lists. Our apologies for
multiple copies.]
LOGIC IN COMPUTER SCIENCE (LICS)
********************************
Ninth Annual IEEE Symposium
July 3-7, 1994, Paris, France
ADVANCE REGISTRATION AND PROGRAM INFORMATION
============================================
[This information is available on the world-wide web at
http://www.research.att.com/lics/
Postscript, dvi, latex and plain text versions of the conference
brochure are available via anonymous ftp from research.att.com in
directory /dist/lics.]
CONFERENCE OFFICE.
=================
Please address registration form and inquiries to
LICS'94 Secretariat
Claudie Thenault
INRIA-Rocquencourt
Relations Exterieures
Domaine de Voluceau BP 105
78153 Le Chesnay Cedex
FRANCE
Phone: 33 (1) 39 63 56 75
Fax: 33 (1) 39 63 56 38
E-mail: symposia@inria.fr
REGISTRATION
============
The registration form should be sent to the conference
office. Registration without payment (or purchase order) enclosed will
not be considered. For early registration, payment must be received
by June 5. Fees will be returned in full for any written cancellation
received before June 24. No refund will be made after this date.
A table of registration fees can be found on the registration form.
The member rate applies to members of ACM, IEEE, EATCS and INRIA,
members of the organizing and program committees and authors of
accepted papers. The student rate applies to full time students; a
copy of the registrant's 1993-94 student card should be included with
the registration form.
The registration fee includes conference participation, a copy of the
proceedings, coffee breaks and an invitation to the welcome reception.
There is a separate charge for the banquet.
Payment must be in French currency, and can be made by bank cheque,
postal cheque, or foreign draft made payable to "Agent Comptable de
l'INRIA", by bank transfer to Tresorerie Generale des
Yvelines, Versailles, account number 10071-78000-00044009 15389, by
postal transfer to CCP Paris---30041-00001-09099 45 B 020-31, or
by institutional purchase order. We have applied for permission to
allow registration by credit card, and hope to have confirmation of
this possibility by May 1. Participants wishing to use this facility
should contact our office at that time, preferably by email addressed
to symposia@inria.fr. Bank transfers should specify registrant's name
and "Conference reference LICS94".
ACCOMMODATION
=============
Reservations can be made through the Wagonlit Travel Agency. The
accommodation form should be sent with deposit before June 1 to:
Wagonlit Travel
Departement Congres & Evenements
50 Rue de Londres
75008 Paris
FRANCE
Tel: 33 (1) 44 90 33 10
Fax: 33 (1) 44 90 33 15
There are two categories of hotels available, as well as inexpensive
student lodging (no age limit) in an international center in Clichy
(north Paris). Paris is very popular in the summer, so reservations
should be made as soon as possible.
A deposit is compulsory for hotel reservations, and student lodging
must be entirely prepaid. Payment must be in French currency, and can
be made by bank cheque, Eurocheque, or foreign draft made payable to
"Wagonlit Travel", by bank transfer to the account 00021935201/61
B.N.P. Paris Saint Lazare, bank code 30004, branch code 0819,
"Wagonlit Travel---code comptable 04/670", or by credit card. Hotel
deposits will be forwarded to the hotel less 60FF for reservation
fees. The participant's bank charges must be added to the amount
transferred.
For cancellations made before June 1, payments will be refunded less
60FF for fees; no refunds will be made after June 1.
LOCATION
========
The Conference is being hosted by the Conservatoire National des Arts
et Metiers (CNAM) and will be part of its Bicentennial celebration.
CNAM is a well-known engineering school where professionals are taught
by professionals. It houses the famous Musee National Des Arts et
Techniques, and is located at 292 Rue Saint Martin in the old center
of Paris, on the right bank of the river Seine. It is walking
distance from Les Halles, the Centre National d'Art et de Culture
Georges-Pompidou (Beaubourg), the Hotel de Ville (City Hall) and the
cathedral Notre-Dame de Paris. The nearest Metro station is Arts et
Metiers.
Paris normally enjoys pleasant summer weather in early July. Days are
warm, but nights may be cool. For general information on Paris,
contact the Paris Tourist Information Office, 127 Champs Elysees,
75008 Paris, phone number 33 (1) 49 52 53 54.
RECEPTIONS
==========
A Welcome Reception will be held on Sunday evening (17:00-19:00) in a
gallery of CNAM. The Conference Banquet will be held in the palace
housing the Senate, the upper chamber of the French Parliament. The
palace was built in the beginning of the 17th century for Marie de
Medicis, widow of King Henry IV. It is located in the well-known
Jardins du Luxembourg. To reserve a place at the banquet, the
appropriate column on the registration form must be marked; a banquet
reservation on site will not be possible.
LOCAL ARRANGEMENTS
==================
Lunches are at the participants' own expense. Participants may eat in
cafes and restaurants in CNAM's vicinity. Telephone messages will be
delivered to participants during breaks. Access to email will be
possible from CNAM.
The organizers cannot be held liable to conference participants for
injury, damage or loss of their personal property. It is suggested
that participants make their own insurance arrangements.
REGISTRATION DESK
=================
A registration and information desk located at the conference site
will operate on Sunday, July 3, from 15:00 to 18:00, and on the
remaining conference days from 8:00 to 18:00.
TRAVEL
======
Paris has two airports, Roissy-Charles de Gaulle, 30km north of
Paris, and Orly, 20km south of Paris. A frequent Air France bus
service goes from Roissy to Place Charles de Gaulle-Etoile or Porte
Maillot in central Paris (the cost is about 48FF); from Orly the bus
goes to Invalides and stops on demand at Montparnasse (32FF). There
is also train service. From Roissy, the RER B line goes to Gare du
Nord or Chatelet; from Orly, the Orlyval goes to Antony where there
is a connection to the RER B (32FF). A taxi from Orly to central
Paris costs about 150FF; from Roissy, 200FF.
The Metro offers a convenient way to get around the city. Each trip
(with unlimited transfers) costs one ticket. Tickets can be bought
individually, but a carnet of 10 is more practical. RER lines
to the suburbs connect with the Metro and cost more. Both Metro
and RER tickets can be purchased from ticket booths or machines.
A 40-45% discount may be obtained from AIR INTER for French domestic
blue and white flights, depending on the days of departure. A voucher
can be requested on the registration form.
Participants requiring a visa for entry into France are strongly
advised to make their application in their home countries at least two
months prior to departure date.
LICS'94 REGISTRATION FORM
*************************
Last Name __________________________________________________
First Name _________________________________________________
Affiliation ________________________________________________
Street Address _____________________________________________
_______________________________________________________
City _______________________________________________________
State/Zip __________________________________________________
Country ____________________________________________________
Phone(s) ___________________________________________________
Fax ________________________________________________________
E-mail _____________________________________________________
REGISTRATION RATES. The fees below are in French currency and include
18.6% VAT. Please circle the applicable fees.
through June 5 from June 6
Regular 2200 2600
Member 1700 2100
Student 1000 1200
Banquet 300 300
Total Fee ___________________________________________________
Rate justification __________________________________________
Full-time student at ________________________________________
I need an AIR INTER discount form: Yes / No
Payment (circle one): Cheque (Bank/Foreign Draft)
/ Purchase Order
/ Bank Transfer (include copy)
LICS'94 ACCOMMODATION FORM
**************************
to be returned before Jun 1
Last Name __________________________________________________
First Name _________________________________________________
Company ____________________________________________________
Street Address _____________________________________________
_______________________________________________________
City _______________________________________________________
State/Zip __________________________________________________
Country ____________________________________________________
Phone(s) ___________________________________________________
Fax ________________________________________________________
1A. HOTEL. Please reserve:
*...twin bed room shared by 2 persons
*...single room
in a hotel of ________ stars, for ________ nights,
from _________________ to _________________(a.m.).
Average rates in French currency, per room and per night,
room only, taxes and service included:
Category Single/Twin Deposit
2** 385/500 460
3*** 550/700 760
1B. YOUTH HOSTEL. Please reserve:
*...bed in a twin bed room, bathroom and toilets outside the
room, compulsory stay of 4 nights (July 3 to 7, 1994),
continental breakfast included, full prepayment compulsory, fixed
rate per person 4 nights: 600FF.
2. PAYMENT. Deposit/prepayment of ____________ FF
Circle one: Visa / Eurocard / Mastercard
/ Cheque (Bank/Euro/Foreign Draft)
/ Bank Transfer (include copy)
Credit card # __________________________ Exp. __________
Signature _____________________________ Date ___________
CONFERENCE PROGRAM
******************
SUNDAY, July 3
==============
REGISTRATION (15:00-18:00)
WELCOME RECEPTION (17:00-19:00)
MONDAY, July 4
==============
REGISTRATION (8:00-9:00)
OPENING ADDRESSES (9:00-9:25)
INVITED LECTURE I (9:25-10:25)
Chair: Robert Constable (Cornell)
Rod Burstall (Edinburgh), Lambda-terms, proofs and refinement
SESSION 1: FINITE MODEL THEORY (10:50-12:30)
Chair: Daniel Leivant (Indiana)
10:50 McColm's Conjecture,
Yuri Gurevich (Michigan), Neil Immerman (U Mass) & Saharon Shelah
(Hebrew U & Rutgers)
11:15 The expressive power of finitely many generalized quantifiers,
Anuj Dawar (Swansea) & Lauri Hella (Helsinki)
11:40 Generalized quantifiers for simple properties,
Martin Otto (RWTH Aachen)
12:05 How to define a linear order on finite models,
Lauri Hella (Helsinki), Phokion Kolaitis (UC Santa Cruz), & Kerkk
Luosto (Helsinki)
LUNCH (12:30-14:00)
SESSION 2: CONCURRENCY (14:00-15:15)
Chair: Vaughan Pratt (Stanford)
14:00 Finitary fairness,
Rajeev Alur (Bell Labs) & Thomas Henzinger (Cornell)
14:25 Bisimulation is not (first-order) equationally axiomatisable,
Peter Sewell (Edinburgh)
14:50 Foundations of timed concurrent constraint programming,
Vijay Saraswat (Xerox PARC), Radha Jagadeesan (Loyola) & Vineet
Gupta (Stanford)
SESSION 3: SEMANTICS I (15:40-16:55)
Chair: Achim Jung (Darmstadt)
15:40 A fully abstract semantics for concurrent graph reduction,
Alan Jeffrey (Sussex)
16:05 An axiomatization of computationally adequate domain-theoretic
models of FPC,
Marcelo Fiore & Gordon Plotkin (Edinburgh)
16:30 On strong stability and higher-order sequentiality,
Loic Colson & Thomas Ehrhard (Marne-la-Vallee)
SESSION 4: DOMAIN THEORY (17:10-18:00)
Chair: Carl Gunter (U Penn)
17:10 Linear types, approximation and topology,
Michael Huth, Achim Jung & Klaus Keimel (Darmstadt)
17:35 Domain theory and integration,
Abbas Edalat (Imperial Coll.)
BUSINESS MEETING (20:00)
TUESDAY, July 5
===============
TUTORIAL I (8:30-9:45)
Chair: Moshe Vardi (Rice)
Ed Clarke (CMU), Model Checking
SESSION 5: CONSTRAINTS (10:00-10:50)
Chair: Harald Ganzinger (MPI Saarbrucken)
10:00 Negative set constraints with equality: an easy proof of
decidability,
Witold Charatonik (Wroclaw) & Leszek Pacholski (Polish Academy of
Sciences)
10:25 Systems of set constraints with negative constraints are
NEXPTIME-complete,
Kjartan Stefansson (Cornell)
SESSION 6: MODAL AND TEMPORAL LOGICS I (11:15-12:30)
Chair: Dexter Kozen (Cornell)
11:15 A compositional proof system for the modal mu-calculus,
Hendrik Reif Andersen (TU Denmark), Colin Stirling (Edinburgh) &
Glynn Winskel (Aarhus)
11:40 On the parallel complexity of model-checking in the modal
mu-calculus,
Shipei Zhang, Oleg Sokolsky & Scott Smolka (SUNY Stony Brook)
12:05 Complexity transfer for modal logic,
Edith Hemaspaandra (Le Moyne)
LUNCH (12:30-14:00)
SESSION 7: TYPES I (14:00-15:15)
Chair: Paris Kanellakis (Brown)
14:00 Typability and type-checking in the second-order lambda-calculus
are equivalent and undecidable,
J.B. Wells (Boston U)
14:25 Efficient inference of object types,
Jens Palsberg (Northeastern)
14:50 Type inference and extensionality,
Adolfo Piperno (Roma) & Simona Ronchi della Rocca (Torino)
SESSION 8: CONSTRUCTIVE MATHEMATICS (15:40-16:55)
Chair: Daniel Leivant (Indiana)
15:40 A groupoid model refutes uniqueness of identity types,
Martin Hofmann (Edinburgh) & Thomas Streicher (LMU Muenchen)
16:05 A non-elementary speed-up in proof length by structural clause
form transformation,
Matthias Baaz, Christian Fermueller & Alexander Leitsch (TU Wien)
16:30 Upper and lower bounds for tree-like cutting planes proofs,
Russell Impagliazzo (UC San Diego), Toniann Pitassi (UC San Diego)
& Alasdair Urquhart (Toronto)
SESSION 9: COMPLEXITY AND DATABASES (17:10-18:00)
Chair: David McAllester (MIT)
17:10 The power of reflective relational machines,
Serge Abiteboul (INRIA), Christos Papadimitriou (UC San Diego) &
Victor Vianu (UC San Diego)
17:35 A syntactic characterization of NP-completeness,
J. Antonio Medina & Neil Immerman (U Mass)
EVENING LECTURE (19:30-20:30)
Chair: Jean-Pierre Jouannaud (Paris Sud & CNRS)
Corrado Boehm (Roma), An algebraic view of the lambda-calculus
WEDNESDAY, July 6
=================
TUTORIAL II (8:30-9:45)
Chair: Samson Abramsky (Imperial Coll.)
Gerard Berry (CMA),
The semantics of synchronous concurrent languages
SESSION 10: LOGIC PROGRAMMING (10:00-10:50)
Chair: Krzysztof Apt (CWI)
10:00 The declarative semantics of the Prolog selection rule,
Robert Staerk (U Muenchen)
10:25 Semantics of meta-logic in an algebra of programs,
Antonio Brogi & Franco Turini (Pisa)
SESSION 11: LINEAR LOGIC (11:15-12:30)
Chair: Samson Abramsky (Imperial Coll.)
11:15 A multiple-conclusion meta-logic,
Dale Miller (U Penn)
11:40 Proof search in first-order linear logic and other cut-free
sequent calculi,
Patrick Lincoln & N. Shankar (SRI)
12:05 Linear logic, totality and full completeness,
Ralph Loader (Oxford)
LUNCH (12:30-14:00)
SESSION 12: TYPES II (14:00-15:15)
Chair: Frank Pfenning (CMU)
14:00 The emptiness problem for intersection types,
Pawel Urzyczyn (Warsaw)
14:25 Subtyping and parametricity,
Gordon Plotkin (Edinburgh), Martin Abadi (DEC SRC) & Luca Cardelli
(DEC SRC)
14:50 On the Church-Rosser property for expressive type systems and
its consequences for their metatheoretic study,
Herman Geuvers (Nijmegen) & Benjamin Werner (Cornell & INRIA)
SESSION 13: SEMANTICS II (15:40-16:55)
Chair: Prakash Panangaden (McGill)
15:40 A semantics of object types,
Martin Abadi & Luca Cardelli (DEC SRC)
16:05 Passivity and independence,
Uday Reddy (Illinois)
16:30 A general semantics for evaluation logic,
Eugenio Moggi (Genova)
SESSION 14: CATEGORY THEORY (17:10-18:00)
Chair: Glynn Winskel (Aarhus)
17:10 Reflexive graphs and parametric polymorphism,
Edmund Robinson (Sussex) & Giuseppe Rosolini (Genova)
17:35 Categories, allegories and circuit design,
Carolyn Brown (Sussex) & Graham Hutton (Chalmers)
BANQUET
THURSDAY, July 7
================
INVITED LECTURE II (9:00-10:00)
Chair: Gerard Huet (INRIA)
Henk Barendregt (Nijmegen),
Results and problems related to proof-checking
SESSION 15: REWRITING (10:00-10:50)
Chair: Jean-Pierre Jouannaud (Paris Sud & CNRS)
10:00 Rewrite techniques for transitive relations,
Leo Bachmair & Harald Ganzinger, (Max-Planck-Institut)
10:25 Normalised rewriting and normalised completion,
Claude Marche (CNRS & INRIA)
SESSION 16: LAMBDA-CALCULUS (11:15-12:30)
Chair: Jean-Jacques Levy (INRIA)
11:15 Modularity of strong normalization and confluence in the
algebraic lambda-cube,
Franco Barbanera (Torino), Maribel Fernandez (Paris Sud & CNRS),
& Herman Geuvers (Nijmegen)
11:40 Cyclic lambda graph rewriting
Zena Ariola (U Oregon) & Jan Willem Klop (CWI)
12:05 Paths in the lambda-calculus,
Andrea Asperti (Bologna), Vincent Danos (CNRS & Paris 7), Cosimo
Laneve (INRIA & CMA), & Laurent Regnier (CNRS)
LUNCH (12:30-14:00)
SESSION 17: MODAL AND TEMPORAL LOGIC II (14:00-15:15)
Chair: Colin Stirling (Edinburgh)
14:00 A trace based extension of linear time temporal logic,
P.S. Thiagarajan (SPIC Madras)
14:25 Axioms for knowledge and time in distributed systems with
perfect recall,
Ron van der Meyden (NTT Tokyo)
14:50 Compositional verification of real-time systems,
Edward Chang (Stanford), Zohar Manna (Stanford), & Amir Pnueli
(Weizmann Institute)
SESSION 18: LOGIC IN ARTIFICIAL INTELLIGENCE (15:40-16:55)
Chair: Peter Schroeder-Heister (Tuebingen)
15:40 Logical bilattices and inconsistent data,
Ofer Arieli & Arnon Avron (Tel Aviv)
16:05 A modal logic for subjective default reasoning,
Shai Ben-David & Rachel Ben-Eliyahu (Technion)
16:30 Language completeness of the Lambek calculus,
Mati Pentus (Moscow State)
SESSION 19: AUTOMATED DEDUCTION} (17:10-18:00)
Chair: Gerard Huet (INRIA)
17:10 Rigid E-unifiability is NEXPTIME-complete,
Jean Goubault (Bull)
17:35 Higher-order narrowing,
Christian Prehofer (TU Muenchen)
END OF CONFERENCE
CONFERENCE ORGANIZATION
***********************
LICS General Chair: Robert L. Constable
1994 Conference Co-chairs: Gerard Huet & Jean-Pierre Jouannaud
1994 Program Chair: Samson Abramsky
Publicity Co-chairs: Amy Felty & Douglas Howe
1994 Local Arrangements: A. Theis-Viemont & C. Thenault
PROGRAM COMMITTEE:
==================
S. Abramsky, K. Apt, H. Ganzinger, C. Gunter, A. Jung,
P. Kannelakis, D. Kozen, D. Leivant, J.-J. Levy,
D. McAllester, P. Panangaden, F. Pfenning, V. Pratt,
P. Schroeder-Heister, C. Stirling, G. Winskel.
ORGANIZING COMMITTEE:
=====================
M. Abadi, S. Abramsky, S. Artemov, A. Borodin, A. Bundy, S. Buss,
E. Clarke, R. Constable (Chair), A. Felty, U. Goltz, Y. Gurevich,
S. Hayashi, D. Howe, G. Huet, J.-P. Jouannaud, D. Kapur, C. Kirchner,
P. Kolaitis, R. Kosaraju, D. Kozen, D. Leivant, A.R. Meyer, D. Miller,
J. Mitchell, Y. Moschovakis, M. Okada, P. Panangaden, A. Pitts,
G. Plotkin, J. Remmel, S. Ronchi della Rocca, G. Rozenberg, A. Scedrov,
D. Scott, J. Tiuryn, M.Y. Vardi.
Date: Thu, 7 Apr 1994 15:37:53 +0500 (GMT+4:00)
Subject: ftp papers
Date: Thu, 7 Apr 1994 07:52:04 -0400
From: Jim Otto
~ftp/pub/otto/README
One can get here by
ftp triples.math.mcgill.ca
cd pub
cd otto
Currently here is compressed postscript
-r--r--r-- 1 otto 137111 Apr 6 10:18 k-ls-p.ps.Z
-r--r--r-- 1 otto 52987 Apr 6 09:43 linti.ps.Z
of the papers
Kalmar, linear space, and P
The linear time hierarchy via
tiers and monoidal categories
The 1st paper has recently been lightly revised. But some of the
ideas there have evolved past what is written there. The 2nd paper is
more recent and hasn't been here before.
ghostview, version 1.5, can preview these, when uncompressed, and save
marked pages.
For comments or help please contact
Jim Otto
otto@math.mcgill.ca
Date: Thu, 7 Apr 1994 15:54:50 +0500 (GMT+4:00)
Subject: local homeomorphisms
Date: Thu, 7 Apr 1994 17:07:35 +0200
From: kock@mi.aau.dk
Re: local homeomorphisms, and etendues
Comment on Feldman's description of binary products in the
category of spaces and local homeomorphisms.
The product of an object X with itself is always the (object
of arrows of) a groupoid, usually a rather uninteresting one.
But in the category of spaces and local homeomorphisms, it is
a very interesting groupoid, usually denoted \Gamma X (the
pseudogroup of (germs of) local automorphisms of X, considered
by Haefliger (and others?) back in the 1950's. It is also a
groupoid in the category of spaces and all continuous maps,
since pull-backs are preserved by the forgetful functor.
For similar reasons, X times Y is a principal bundle over
the groupoid \Gamma X (acting from the left), and \Gamma Y
(acting from the right).
Similar considerations apply in the category of locales. The
corresponding localic groupoids were in essence considered by
Ehresmann in "Gattungen von lokalen Strukturen", under the
name of _local_ groupoids. I presented an expose about this,
and its relatinship to etendue theory at the PSSL in Sussex in
March, and the manuscript I circulated, may be picked up by
ftp from theory.doc.ic.ac.uk, directory papers/Kock. It is
called sussex.dvi.
Anders Kock
Date: Thu, 7 Apr 1994 15:53:19 +0500 (GMT+4:00)
Subject: colloquium
Date: Thu, 7 Apr 94 14:32:45 +0200
From: Giuseppe.Longo@ens.fr
LOGICAL RATIONALITY AND GEOMETRIC INTUITION
"Rationalite' logique et intuition geometrique"
Paris, 9 and 10 June 1994
Ecole Normale Superieure, 45, rue d'Ulm, Salle Dussane
75005 Paris
Jointly organised by the Departement Mathematiques et Informatique de
l'ENS, CREA (Ecole polytechnique - CNRS) and the Institut d'histoire
et de philosophie des sciences et des techniques (Paris I - CNRS)
Organizers: Daniel Andler (CREA & Paris X - Nanterre),
Giuseppe Longo (CNRS, ENS) et Hourya Sinaceur (CNRS, IHPST)
Thursday June 9, 1994
9h30 Ouverture du colloque: E. Guyon (Directeur, ENS)
10h Rene Thom (IHES) : L'efficacite' pragmatique des
mathematiques est-elle due a` la logique ou a` l'intutition
geometrique?
10h50 Repondant : Giuseppe Longo (ENS)
11h15 Discussion
12h Aperitif
14h Alain Berthoz (College de France) : La geometrie euclidienne
a-t-elle des fondements dans l'organisation des systemes sensoriels
et moteurs ?
14h50 Repondant : Frederic Nef (Universite de Rennes)
15h15 Discussion
15h50 Pause
16h10 Jean Petitot (EHESS) : Logique geometrique et statut modal
de l'espace
17h Repondant : Bernard Teissier (ENS)
17h25 Discussion
Friday June 10
9h Dana Scott (Carnegie Mellon University) : Infinitesimals
9h50 Repondant : David Miller (Warwick College)
10h15 Discussion
10h50 Pause
11h10 Pierre Cartier (ENS)Algebrisation de la geometrie (et vice
versa)
12h Repondant : Marie-FranIoise Roy (universite de Rennes)
12h25 Discussion
14h30 Lamberto Maffei (Scuola Normale Superiore, Pise) :
What Galileo's brain told Galileo's eye
15h20 Repondant : Jacques Ninio (ENS)
15h45 Discussion
16h20 Pause
16h30 Daniel Andler (CREA) : Synthese des journees
Information: auffray@dmi.ens.fr
Date: Thu, 7 Apr 1994 23:08:35 +0500 (GMT+4:00)
Subject: Workshop on Log., Lang., Inf. & Comp.
Date: Thu, 07 Apr 1994 16:31:48 -0500 (EST)
From: Ruy de Queiroz
(PLEASE NOTE NEW DEADLINE, AND NEW INVITED SPEAKER)
Workshop on Logic, Language, Information and Computation
WoLLIC '94
July 28--30, 1994
Recife, Brazil
A Workshop on Logic, Language, Information and Computation, will be held
in Recife, on the northeastern coast of Brazil, from 28th to 30th July 1994.
Contributions are invited in the form of one page (300 words) abstract in all
areas related to logic, language, information and computation, including: pure
logical systems, proof theory, model theory, type theory, constructive
mathematics, lambda and combinatorial calculi, program logic and program
semantics, nonclassical logics, nonmonotonic logic, logic and language,
discourse representation, logic and AI, automated deduction, foundations of
logic programming, logic and computation, and logic engineering.
There will be a number of guest speakers, including some who are already part
of the advanced seminars of the parallel event (see below):
J. Barwise (Indiana), J. Cunha (Porto), J. Fiadeiro (Lisbon),
D. Gabbay (London), J. Lambek (McGill), T. Maibaum (London).
Four others have confirmed their participation: N. da Costa (Sao Paulo),
H. J. Ohlbach (Saarbruecken), U. Reyle (Stuttgart), K. Segerberg (Uppsala).
Submission: One page abstracts (preferably by e-mail to the address
*** wollic94@di.ufpe.br ***) must be RECEIVED by **MAY 15, 1994**.
Authors will be notified of acceptance by June 5, 1994. WoLLIC '94 is
sponsored by the Interest Group in Pure and Applied Logics (IGPL) and The
European Foundation for Logic, Language and Information (FoLLI). Abstracts from
members of the IGPL will be published in the Bulletin of the IGPL
(ISSN 0945-9103) as part of the meeting report. Selected contributed papers
will be invited for submission to a special issue of the Bulletin.
The Workshop will be part of a bigger event being held in Recife during the last
week of July 1994: the (Brazilian) IXth School of Computing, a large biennial
event in computer science in the context of Latin America. As some of the
invited speakers for the Workshop will be giving advanced seminars (in the form
of short courses) on logic and computation in the School, the Workshop will
benefit from the fact that the School will attract a fair number of young
researchers and students in computer science from all over Latin America.
(The School is expected to have an audience of approx. 600 participants.)
The location: Recife is the capital of the sun belt coast in the northeast
of Brazil, just 8 degrees below Equator, bathed by 250+ days of sun/year (i.e.
Caribbean-like climate). City population is around 2.5 million and the life
style is quite relaxed. Recife is over 450 years old, has a number of
interesting architectural samples of Portuguese colonial times (esp. XVII and
XVIII centuries), and is neighbour to picturesque Olinda, whose architectural
heritage is protected by UNESCO.
Programme Chair: Prof P. A. S. Veloso, Attn: WoLLIC '94, Departmento de
Informatica, PUC-Rio, Rua Marques de Sao Vicente, 225, Rio de Janeiro, RJ
22453-900, Brazil, veloso@inf.puc-rio.br, tel: +55 21 529 9524,
fax: +55 21 511 5645. (Please send abstracts to wollic94@di.ufpe.br)
Programme Committee: W. A. Carnielli (UNICAMP, Campinas), M. Costa (EMBRAPA,
Brasilia), V. de Paiva (Cambridge, UK), R. de Queiroz (UFPE, Recife),
A. Haeberer (PUC, Rio), T. Pequeno (UFC, Fortaleza), L. C. Pereira (PUC, Rio),
A. M. Sette (UNICAMP, Campinas), P. Veloso (Chair, PUC, Rio).
For further information, contact the Chair of Organising Committee:
R. de Queiroz, Departamento de Informatica, Universidade Federal de Pernambuco
em Recife, Caixa Postal 7851, Recife, PE 50732-970, Brasil, tel:+55 81 271 8430,
fax +55 81 271 4925, ruy@di.ufpe.br.
Co-Chair: Tarcisio Pequeno, LIA, Universidade Federal do Ceara,
tarcisio@lia1.ufc.br, fax +55 85 223 1333.
Date: Mon, 11 Apr 1994 16:26:44 +0500 (GMT+4:00)
Subject: postdoctorate stay
Date: Fri, 8 Apr 1994 11:26:24 +0200 (MET DST)
From: Jiri Rosicky
Department of Mathematics, Masaryk University, Brno, Czech Republic
offers a postdoctorate position for the period September (October) -
December 1994. Send applications together with C.V. by May 10 to
A.Sekaninova
Department of Mathematics
Masaryk University
Janackovo nam. @a
66295 Brno
Czech Republic
fax: 425-41210337
e-mail: asekanin@math.muni.cz
Date: Mon, 11 Apr 1994 16:27:58 +0500 (GMT+4:00)
Subject: FMCS 94 Accomodation
Date: Fri, 8 Apr 94 13:48:15 -0700
From: John MacDonald
University of British Columbia
REQUEST FOR ACCOMMODATION AT WALTER GAGE COMPLEX
Foundational Methods in Computer Science, June 2-5, 1994
---------------------------------------------------------------------
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city:. . . . . . . . . . state/province: . . . . . zip/postcode: . .
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Arrival Date, Month: . . . . . . . . . Day: . . . . . . . . . . . .
CHECK IN after 2:00 pm
Departure Date, Month: . . . . . . . . . Day: . . . . . . . . . . . .
CHECK OUT before 11 am
Shared Washroom [ ]Single room with shared washroom $32.00 room/night
Private Washroom [ ]Single room (single bed) . . . .$52.00 room/night
[ ] Suite (double bed) . . . . . . $70.00 room/night
[ ] Deluxe suite (twin beds; living room with TV,
telephone, sofa-bed; kitchenette) . . . . . . . . . $91.00 room/night
If requesting a Suite, please advise number of people: [ ]
PAYMENT INFORMATION. Full payment in Canadian funds is due at
check-in by cash, travellers' cheques, VISA or MasterCard (no
personal cheques). There is no guarantee required for shared
washroom accommodation. However, private washroom accommodation has
to be guaranteed with VISA or MasterCard or with deposit by bankdraft
in Canadian funds for the equivalent of one night. A one-night
cancellation charge applies if cancellation in writing is not
received 48 hours prior to check-in-date.
[ ] VISA [ ] MASTERCARD Expiry Date: (Month: Year: )
CARD NO: ____________________________________________________
CARDHOLDER'S SIGNATURE: _____________________________________
DATE SIGNED: _______________________________________________
Group Code G40602A
======================================================================
Please mail or fax the form above before May 2, 1994, to:
Reservations Office, UBC Conference Centre, 5901 Student Union Blvd.,
Vancouver, BC, V6T 2C9, Canada. Tel: (604) 822-1010, Fax: (604)
822-1001
Single rooms with shared washroom will be substituted when requests
for private washroom cannot be accommodated. All rates are quoted in
Canadian funds and are subject to applicable taxes.
----------------------------------------------------------------------
Remarks from organizers:
1. Please send the above reservation form either by fax to the
number given or by paper mail to the Reservations Office at the above
address.
2. Please do not send reservation forms to the organizers.
3. Please note that accomodation should be booked before May 2,
1994. This accomodation is within easy walking distance of the talks
and the student cafeteria.
4. Only a limited amount of accomodation has been booked. Thus if
attendance is significantly higher than last year then available
space may run out. Early reservations are recommended.
5. If you choose to stay in a Vancouver hotel then you will need to
come in to the talks each day by bus or car. You should make such
bookings yourself directly or through a travel agent since we will be
unable to handle hotel bookings, due to the volume of other
correspondence.
John MacDonald & Art Stone, organizers
Date: Thu, 14 Apr 1994 16:58:41 +0500 (GMT+4:00)
Subject: postdoc
Date: Wed, 13 Apr 94 18:02:13 EDT
From: Michael Barr
It turns out that despite my doubts, we did get the grant from the
province that we had applied for and it seems we can support one postdoc.
I forgot to check what the salary is, but it is probably in the vicinity
of $30K and can be topped up a bit with some teaching, which the chairman
says is still available. We have two applications already and I will
consider others. Please send an application and two letters of reference
to me if you are interested. I will be away from April 21 to May 1, so let
me say that the letters should be in my hand by May 1. Fax and email accepted.
The fax number is (514) 398-3800 and my name should be on it.
Michael Barr
Date: Thu, 14 Apr 1994 16:59:20 +0500 (GMT+4:00)
Subject: change it
Date: Thu, 14 Apr 94 17:03:10 BST
From: Dusko Pavlovic
In the last couple of weeks, I kept catching myself in --- uhm ---
philosophical discussions re. category theory. They were a bit hectic,
and didn't get very far... You know, for most mathematicians,
philosophy is a no-go area; one takes care not to get too
involved. But category theorists seem to be driven to it,
somehow. (Sometimes, at least.)
Anyway, hoping for comments from more experienced people, and
apologizing to those who don't want to be bothered, I would like to
put forward a couple of themes that keep coming back to me.
The starting point for one of those discussions was my paper Maps
II. Why is that simple characterisation so complicated in details?
Doesn't that mean that the setting is wrong? In a more extreme and
less serious form, I've heard a similar objection to somebody else's
work: "It is too complicated to be of interest".
Yes, category theory is the discipline of conceptual mathematics: it
helps us extract the relevant structure and discard the
contingent. "Mental hygiene" is a nice metaphor. Categories provide
means for analyzing complex situations into conceptual parts. In a
sense, they embody the first commandment of the Cartesian Method:
DIVIDE. They are tools of understanding --- so they should at least be
transparent and easy to understand themselves, shouldn't they?
But they are not. The complexity issue arises on a rather general
plan. For instance, in a recent issue of the Advances in Mathematics,
in the review of our 1991 Montreal proceedings, Gian-Carlo Rota says
that it's good that categories are still alive and well, but suggests
that all those papers should be written in two versions --- the second
one for people who might need some encouragement before "swallowing
this morass of definitions". I don't suppose you need to hear the more
extreme and less serious objections this time. Everybody knows that
most mathematicians think of category theory just as their yoga
instructors, their grandmothers and so on think of mathematics: it's
complicated and useless. Of course, yoga instructors are less likely
to be right about maths than mathematicians about categories; and
those objections to my work are probably right, at least to some
extent. So I am not trying to transform a criticism of me into a
criticism of the State. They are quite different --- but somehow
analogous, and I am trying to understand what lies behind. Is the
complexity phenomenon just subjective (and more so in the narrower
part of the telescope) or not? I mean, does the morass arise just from
our wrong settings and overly complicated proofs --- feeding people's
prejudice --- or is there more to it?
Well, I think there is often less! I want to argue for the possibility
that morass is at some places a natural state of ground, AND not
always bad or dangerous. But let me try to put this in less extreme
and more serious terms. (OK, I won't use this figure any more.)
Categories are about understanding. Understanding is a process in
time; but when it is achieved, it can often be summarized in a moment,
captured by a picture. For instance, the periodic system of
elements. In category theory, instead of wandering among equations, we
draw a diagram to see what happens. Even for a hardest theorem, one
often finds a crucial point or two, which can be retained in our
mind's eye. Then we say we understand.
Sometimes, however, understanding is essentially dynamical, and cannot
be fixed. You may understand topology, but you can hardly survey it in
a glimpse, compress it into a single idea. Or take natural language:
we understand sentences as they go, without memorizing them or trying
to capture the structure. In the morass of language, we move like
centipedes, not worrying which leg comes after the 32nd.
In mathematics and exact sciences, one tends to be sceptical towards
this dialectical kind of understanding. The imperative of logical
certainty seems to preclude it. "Clare et distincte", commanded
Cartesius, and his voice still resounds very clearly. Mathematics
takes good care not to become a natural language! Things should be
cristal clear. Even a philosopher like me gets this. But when I look
at our concrete mathematics --- there are all those strange phenomena,
more and more of them, leading people to question the feasibility of
the current criteria of logical certainty.
Every month, an important new result is announced, with a proof that
either just computers can check, or less than 7 people around the
globe can hope to understand. Many of these proofs come with gaps ---
but then there is this new branch of computational proof theory which
measures how economic it is to allow such gaps. To a pure pure
mathematician, this is ultimate horror, although it is perhaps better
than the current practice of judging the validity of proofs by the
concensus of experts. (However, some rather serious people argue that
this practice cannot and should not be abolished: Deligne, Thomas
Kuhn.) Experts usually agree whether a gap is easy to be filled or
not, but for that long sought result about packing spheres like
cannonballs, achieved three years ago by Hsiang (I think), the experts
have not been able decide if there is a gap or not. Two equally large
groups are still arguing that there is and that there ain't.
So what can category theory hope for in this heavy-weight world of
gaps and cannonballs? Not only in the granting sense, but also ---
forgive me --- philosophically? Of course, I don't know the
answer. What I wanted to say is that category theory might be some
kind of a natural language, whether we like it or not. Hence the
morass. But, like sentences in natural language, complicated
categorical derivations are usually "simpler than they look", say
I. Children make and understand long sentences, without being able to
capture their structure. Laws of objective dialectics take care that
they don't get lost in the morass. (Otherwise, they could never be
careful enough anyway.) A very distinct experience that I had in
categorical proof theory: derivations get lengthy, sometimes scary;
you get surprised every once in a while --- but in the end, things
always turn out to be tame and natural. I wish more people would visit
the area.
Simplicity, hygiene and logical certainty are, of course, good things
when you can afford them, but "some books would be shorter if they
were not so short", wrote Kant in the foreword of his first
Critique. (Young Wittgenstein did not listen, and wrote that very
hygienic book of his, which ended up in silence.) Ata ny rate, we
should pay more attention to the dialectical contents of our science,
as Lawvere and MacLane have been saying for a long time, more or less
explicitly. This becomes even more important now, when it has become
clear that the dream of powerful, problem-solving category theory
won't come true. Complexities are not all due to a lack of category
theory, and cannot be conceptualized away. We should not try to
simplify the world, but... (But perhpaps I shouldn't philosophize it
too much either.)
Cordially,
Dusko Pavlovic
Date: Fri, 15 Apr 1994 16:28:23 +0500 (GMT+4:00)
Subject: Re: change it
Date: Fri, 15 Apr 94 9:54:10 CDT
From: David Yetter
A few brief thoughts on Dusko's discussion:
First, almost all definitions in mathematics when done from the
ground up are hopelessly complex. Ask your skeptical friends to define
a continuous real-valued function on a topological space from first
principles (for them, I suppose, from axiomatic set-theory alone).
The only reason real numbers (pairs of subsets of the set of
equivalence classes of formal ratios of formal differences of things
satisfying the Peano axioms, modulo... and satisfying.... ) don't give
the same impression is that we are used to them and have consequently
forgotten the formal definition and the proceed to use only the properties.
One way of making progress in mathematical understanding, indeed
the way most congenial to categorists, is to get the definitions right
so that one can forget the morass of quantifiers in the definition, and use
only the essential properties of the objects under consideration.
(Deep results, though, usually come from doing this, then briefly returning
to the less abstract level to pull out an unexpected relation between the
more abstract and the more concrete: e.g. the Atiyah-Singer Index Theorem,
or Shum's freeness result for framed tangles.)
It has been a persistent problem for category theory that we are
interested in foundational questions (which most mathematicians abhor), and
have not made it generally understood that we are really doing a kind
of algebra (albeit a kind of algebra so potent that it can be applied to
foundations).
You might therefore turn aside much criticism by pointing out
that category theory is no longer abstract in the sense of having no
really interesting concrete examples: the work of Joyal/Street,
Freyd/Yetter, Shum, Turaev, Reshtikhin, Majid, Lyubashenko, (the physicists)
Moore/Seiberg, Kapranov/Voevodsky, and Fisher (to name but a few) are
full of remarkable categories (with additional structure requiring yet
more complex definitions!) with intimate connections to low-dimensional
topology and Hopf algebra theory. Similarly, coming from the more
foundational uses of category theory, the realizability topos is surely one
of the most beautiful objects anywhere. (Indeed, topoi in general are
quite beautiful.)
--David Yetter
Date: Fri, 15 Apr 1994 16:26:46 +0500 (GMT+4:00)
Subject: Re: change it
Date: Fri, 15 Apr 1994 11:08:38 -0400 (AST)
From: RDAWSON@HUSKY1.STMARYS.CA
Dusko Pavlovic raises some interesting points - I just want to
comment quickly on a couple of them. Firstly, it may be that (like those
annoying "semiconvergent" series in numerical analysis), attempts to
clarify something pass through a point of maximum simplicity after which
they get worse again. Given all the indications that we can't have the
kind of foundations that were once sought after (Goedel and All That),
perhaps we are just looking for that point?
The other comment addresses the idea that children use complex
grammatical structures without completely understanding them. Sure they
do - but they don't always use them *correctly*. Neither, of course, do
adults. The trouble with mathematics is that unlike most of what we use
natural language for, its groundrules don't (despite certain recent articles)
permit statements on the 'well, it's mostly right and everybody knows what
I mean' level. Most natural language usage jumps out of the system all
the time... which gets into the AI debate. In mathematics, the medium is much
closer to being the message.
We try not to get into situations similar to the old chestnut
"Time flies like an arrow, while fruit flies like a banana." , supposed by
some to show that computers can't parse English. (I'm not sure that it does,
any more than if I say 'Professor Smith is visiting next week' and you
don't know whether to ask 'Is he?' or 'Is she?' , that shows that *you*
don't know how to parse English...) But natural languages do, because in
"natural" situations there is something outside the linguistic universe that
can be referred to usefully.
-Robert Dawson
Date: Fri, 15 Apr 1994 16:30:59 +0500 (GMT+4:00)
Subject: position available
Date: Fri, 15 Apr 94 17:41:01 METDST
From: Peter Knijnenburg
Leiden University - The Netherlands
The Department of Computer Science
invites applications for a position of
Full Professor of Computer Science
The department offers a master's program in computer science for both
full-time and part-time students, as well as a Ph.D degree in computer
science. It has 18 regular faculty members and a technical support staff.
There are research groups in theoretical computer science, information
systems and software engineering, high performance computing and computer
graphics, CAD and geometric modelling.
Hardware facilities include networks of SUN, HP, Silicon Graphics
workstations, PC networks, a MasPar MP1 multiprocessor system, and a
Parsytec MultiCluster system.
Candidates must have a relevant Ph.D, a strong commitment to teaching,
and a strong record of research accomplishment. Especially desired are
candidates with a proven research record in areas such as programming
languages, semantics, specification, verification, program transformation,
logic, design and analysis of algorithms, and foundations of artificial
intelligence.
For more information please contact the chairman of the search committee,
Professor G. Rozenberg, Department of Computer Science, Leiden University,
Niels Bohrweg 1, NL-2333 CA Leiden, The Netherlands, (tel.: +31-71-277063,
e-mail: rozenber@wi.Leidenuniv.nl, fax: +31-71-276985).
Applications accompanied by a detailed c.v., list of publications, and the
names of at least three references should reach Dr. J. Coremans, Managing
Director, Huygens Laboratory, Niels Bohrweg 2, NL-2333 CA Leiden, The
Netherlands, not later than May 15, 1994.
Date: Fri, 15 Apr 1994 16:35:16 +0500 (GMT+4:00)
Subject: LICS'94 registration and ASL members
Date: Thu, 14 Apr 94 16:48 EDT
From: Amy Felty
LOGIC IN COMPUTER SCIENCE
********************************
Ninth Annual IEEE Symposium
July 3-7, 1994, Paris, France
Please note the following correction to the LICS'94 registration
information: the member rate also applies to members of the
Association for Symbolic Logic.
[Complete program and registration information is available on the
world-wide web at
http://www.research.att.com/lics/
Postscript, dvi, latex and plain text versions of the conference
brochure are available via anonymous ftp from research.att.com in
directory /dist/lics.]
Date: Mon, 18 Apr 1994 16:57:40 +0500 (GMT+4:00)
Subject: Re: change it
Date: Mon, 18 Apr 94 12:52:07 EDT
From: Peter Freyd
Dusko Pavlovic offers, in passing, several descriptions of category
theory:
Yes, category theory is the discipline of conceptual mathematics: it
helps us extract the relevant structure and discard the contingent.
Categories provide means for analyzing complex situations into
conceptual parts.
Categories are about understanding.
We know how to respond to students who tell us that they understand
the material but can't do the problems. So how does one respond to
this? I would suggest that any branch of mathematics is justified
finally only because it allows us to prove things previously
unprovable.
If we were restricted to doing things we understand I don't think we
would have gotten very far. Indeed, the most conspicuous function of
mathematics I know is that it allows us to do things we don't yet
understand. In my experience the feeling of understanding doesn't come
until after the problems are solved. And sometimes long after.
I think there are strong cases to be made for the presence of
categories in mathemamatics (beginning at least with the Adams
operations). And I think there are good cases to made even for the
_theory_ of categories in mathematics. But -- something none of us
expected -- the best cases to be made for the theory of categories are
not in mathematics but in applied areas. It is there that we are
finding the refutation of Dusko's sad assertion "now when it has
become clear that the dream of powerful, problem-solving category
theory won't come true."
Date: Thu, 21 Apr 1994 14:48:54 +0500 (GMT+4:00)
Subject: European Colloquium of Category Theory
Date: Wed, 20 Apr 1994 15:43:27 UTC+0200
From: damphous@univ-tours.fr
EUROPEAN COLLOQUIUM on CATEGORY THEORY in Tours (France)
July 25-29 1994
---- ECCT ----
FIRST ANNOUNCEMENT
(APRIL 20 1994)
A European Colloquium on Category Theory (ECCT) will be held in TOURS
(France) from July 25th to July 29th, the week before the International
Congress of Mathematics in Z\"urich, under the honorary presidency of
Professor Saunders MacLane, with Samuel Eilenberg as guest star.
Mathematicians foreseeing to be present in Europe at that time who whish
to attend or participate are most welcome to pre-registe in order
to receive pertaining information. Paper may still be submitted for
a limited period not exceeding June 1st.
The scientific committee is composed of : J. Adamek (Prague);
J. B\'enabou (Paris); F. Borceux (Louvain); A. Carboni (Genova);
P. Damphousse (Tours); Y. Diers (Valenciennes); R. Guitart (Paris);
J. Gray (Urbana); H. Herrlich (Bremen); P. Johnstone (Cambridge);
M. Kelly (Sidney); I. Moerdijk (Utrecht); G. Reyes (Montreal).
To pre-register, you must proceed as follows:
send an e-mail to ECCT-request@univ-tours.fr,
with the following line in the body of the
message (with no subject in this e-mail):
SUBSCRIBE
For any further information, contact Pierre Damphousse at
damphous@univ-tours.fr
(Note : due to construction works, the computer center at the above
address will close from april 25 to april 28.)
Date: Fri, 22 Apr 1994 15:12:36 +0500 (GMT+4:00)
Subject: Books on categories in computer science
Date: Fri, 22 Apr 94 09:09:54 PDT
From: "Michael J. Healy (206) 865-3123"
I am asking for recommendations for a book. Some industrial
mathematicians and computer scientists are forming a category
theory study group, and want to use a book that gives an
introduction to categories in computer science. We would
like one that is self-contained in that it contains definitions
and, if appropriate, examples for all categorical terms
including those specialized to computer science. We're looking
primarily at applications in specification-based software
synthesis, and design synthesis in general.
If you care to respond, my email address is
mjhealy@atc.boeing.com.
Thank you,
Mike Healy
Date: Mon, 25 Apr 1994 14:00:53 +0500 (GMT+4:00)
Subject: What is a "principal fibration" ?
Cc: cdl2 -- France Dacar ,
Robert Dawson ,
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Bernard Hodgson
Date: Mon, 25 Apr 94 18:40:59 +0200
From: Thomas Streicher
I have heard that in the Grothendieck school there has developed a
notion of "principal fibration" which should generalize the notion of
principal bundle !
Please, could anyone give me a reference !
Thomas Streicher
Date: Mon, 25 Apr 1994 14:00:16 +0500 (GMT+4:00)
Subject: Tortile tensor cats
Date: Mon, 25 Apr 1994 07:52:29 -0400
From: James Stasheff
Mei Chee Shum's `Tortile tensor cats' has appeared in the
latest JPAA 93 (1994) 57-110.
jim
Date: Tue, 26 Apr 1994 15:29:47 +0500 (GMT+4:00)
Subject: Diocletian
Date: Tue, 26 Apr 94 09:19:01 EDT
From: Peter Freyd
It seems that somewhere between 284 and 305 Diocletian proclaimed:
Artem geometriae discere atque exercere publice interest,
ars autem mathematica damnabilis interdicta est omnino.
Does that say what I think it does? Can someone supply an
authoritative translation?
Date: Tue, 26 Apr 1994 15:29:30 +0500 (GMT+4:00)
Subject: RE: What is a "principal fibration" ?
Date: Tue, 26 Apr 94 9:17 GMT
From: MAS013@bangor.ac.uk
I do not remember the notion in Grothendieck's work, but the term
princial fibration was extensively used with simplicial sets. the theory
is very pretty and can be found in the survey by Curtis in Adv. in
Maths. 6 (1971) 107 - 209. Given the close connections between
Simplicial sets and category theory this may provide a solution to your
problem.
Tim Porter
mas013@uk.ac.bangor
Date: Tue, 26 Apr 1994 22:37:39 +0500 (GMT+4:00)
Subject: Re: What is a "principal fibration" ?
Date: Tue, 26 Apr 1994 18:57:44 -0400
From: James Stasheff
hadn't heard of that one
but there is a notion of principal fibration in alg top/homotopy theory
the based path space with loop space as fibre is the stereotypical
example
jim
Date: Tue, 26 Apr 1994 22:41:35 +0500 (GMT+4:00)
Subject: Re: Diocletian (times 3)
Date: Tue, 26 Apr 94 13:44:46 PDT
From: "Scott L. Burson"
Date: Tue, 26 Apr 94 09:19:01 EDT
From: Peter Freyd
It seems that somewhere between 284 and 305 Diocletian proclaimed:
Artem geometriae discere atque exercere publice interest,
ars autem mathematica damnabilis interdicta est omnino.
Does that say what I think it does? Can someone supply an
authoritative translation?
Yep, it means just what it looks like:
To learn and practice the art of geometry is publicly of interest, but the
damnable mathematical art is proscribed altogether.
-- Scott
++++++++++++++++++++++++++++++
Date: Tue, 26 Apr 94 20:14:21 EDT
From: Moez Alimohamed
Peter Freyd's writes:
It seems that somewhere between 284 and 305 Diocletian proclaimed:
Artem geometriae discere atque exercere publice interest,
ars autem mathematica damnabilis interdicta est omnino.
Does that say what I think it does? Can someone supply an
authoritative translation?
-------------------------------
In translation, this reads:
Learning the art of geometry and furthermore, using it on behalf of the
state is of interest - nevertheless, mathematics is altogether worthy of
condemnation and is forbidden.
Very strongly worded.
Date: Tue, 26 Apr 94 20:17:54 EDT
From: Moez Alimohamed
The translation of Diocletian contained in the previous
posting is due to the mathematician and Latin scholar
Raymond Thomas (rlt@cunyvms1.gc.cuny.edu)
++++++++++++++++++++++++++++++++++++++++++++++++++++
Date: Tue, 26 Apr 94 21:00:23 EDT
From: Walter
My translation would be:
"To learn and (especially) to practice the art of geometry is generally
of importance (or: is in the public interest) ,
the condemnable art of mathematics, however, is altogether forbidden."
Walter Tholen.
Date: Wed, 27 Apr 1994 13:15:19 +0500 (GMT+4:00)
Subject: More on geometriae/mathematica
Date: Wed, 27 Apr 94 14:54:11 +1000
From: Max Kelly
The Latin of Peter Freyd's quotation from Diocletian may be translated:
To teach and exercise the art of geometry is in the public interest; the
damnable art of mathematics, however, is forbidden to every man.
The point, surely, is that in those days "mathematics" meant "astrology".
See Augustine, in The City of God, if I recall correctly. In the twelfth
century "Play of Daniel", as performed at Beauvais, when the writing on the
wall appears, the king says "Vocate mathematicos" - "call the soothsayers
(or astrologers).
Regards, Max Kelly.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Date: Wed, 27 Apr 94 01:49:18 EDT
From: Peter Freyd
The mysterious proclamation of Diocletian,
Artem geometriae discere atque exercere publice interest, ars autem
mathematica damnabilis interdicta est omnino.
(To learn and -- especially -- to practice the art of geometry is in
the public interest but the damnable mathematical art is proscribed
altogether.)
was found as a citation for the once common use of the word
"mathematicus" to mean "wizard". Another citation is from England
(from Shirley's 1642 comedy "The Sisters"):
Giovanni: Master Steward, yonder are the rarest fellows! In such
fantastical habits too; they call themselves mathematicians.
Steward: What do they come for?
Giovanni: To offer their service to my Lady and tell fortunes.
...
Antonio: Her house is open for these mountebanks,
Cheaters, and tumblers, that can foist and flatter
My lady Gewgaw...
What are you, sir?
Strozzo: One of the mathematicians, noble Signior.
Antonio: Mathematicians! mongrel,
How durst thou take that learned name upon thee?
You are one of those knaves that stroll the country,
And live by picking worms out of fools' fingers.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Date: Wed, 27 Apr 1994 10:56:41 -0400 (EDT)
From: MTHISBEL@ubvms.cc.buffalo.edu
The three translations I have seen here are very nice except for the meaning.
*Geometry* means pretty much #mathematics#. *Mathematics* is #divination#. John
Date: Thu, 28 Apr 1994 16:33:27 +0500 (GMT+4:00)
Subject: The last of Diocletian
Date: Thu, 28 Apr 94 08:53:01 +0100
From: Gavin Wraith
A propos the Diocletian quote, I support Max Kelly and John Isbell :
I do not like to jump in with both feet without seeing the locus and
its context, but I would say that the sense is
"Surveying is generally acknowledged to be a social benefit but
astrology is everywhere taken to be pernicious"
"Geometria" at this time would have military overtones - design of
fortifications, disposal of forces over terrain etc. "Mathematicus"
almost certainly means "astrologer" or "soothsayer". Astrology was
not respectable, being seen as a vulgar oriental import. Two centuries
earlier, Juvenal in his sixth satire (line 562) says
"Nemo mathematicus genium indemnatus habebit"
(No astrologer gets a reputation until he is convicted)
a line which the Diocletian quote could well be referring back to.
Sorry if this is a disappointment - but a nice quote anyhow!
-- Gavin Wraith
++++++++++++++++++++++++++++++++++++++
Date: Thu, 28 Apr 1994 11:30:58 +0200
From: France.Dacar@ijs.si
> Date: Tue, 26 Apr 94 13:44:46 PDT
> From: "Scott L. Burson"
>
>
> Date: Tue, 26 Apr 94 09:19:01 EDT
> From: Peter Freyd
>
> It seems that somewhere between 284 and 305 Diocletian proclaimed:
>
> Artem geometriae discere atque exercere publice interest,
> ars autem mathematica damnabilis interdicta est omnino.
>
> Does that say what I think it does? Can someone supply an
> authoritative translation?
>
> Yep, it means just what it looks like:
>
> To learn and practice the art of geometry is publicly of interest, but the
> damnable mathematical art is proscribed altogether.
>
> -- Scott
Appearances might be misleading. What precisely were the
meanings of "geometria" and "mathematica" in Diocletian times?
I suspect that "geometria" encompassed what we would call the
whole of mathematics as known then, while "mathematica" was a
branch of sorcery (benign as well as malign, ie. both white
and black) that involved much high-fallutin' twiddling of
symbols, mysterious diagrams and geometric figures, and such --
thus a kind of formalized abstract magick. (Some recent
literature on uses of category theory in computer science in
general and in AI in particular would be basic manuals, as it
were, for those mathematically inclined sorcerers. They could
use them quite effectively even if they would not understand what
it's all about, since they could always pretend they do, and they
were masters of illusionism.)
Can somebody tell whether this is a good enough guess?
------------------------------------------------------------------------
France Dacar Email: france.dacar@ijs.si
Computer Science Department Phone: +386 61 1-259-199 / 768
Jozef Stefan Institute Fax: +386 61 1-258-058
Jamova 39, 61000 Ljubljana, Slovenia
Date: Thu, 28 Apr 1994 16:30:10 +0500 (GMT+4:00)
Subject: Cubical monads
Date: Thu, 28 Apr 1994 15:15:13 +0200
From: Marco Grandis
The following preprint is available
"Cubical homotopical algebra and cochain algebras"
Marco Grandis.
Abstract. Basic homotopical algebra is developed in a setting consisting of
a cubical monad (*), i.e. a cylinder endofunctor I, equipped with
connections g-, g+: I^2 -> I, and - possibly - with symmetries extending
the reversion r: I -> I and the interchange s: I^2 -> I^2 of the
standard topological case. Our study is mostly concerned with the Puppe
sequence of a map f and its comparison with the sequence of iterated
homotopy cokernels of f. As an application, the homotopy structure of
cochain algebras is studied in the present frame, through the cubical
co-monad of the path functor P and the left adjoint cylinder functor I.
This paper is a sequel of
(*) "Cubical monads and their symmetries",
whose abstract appeared in "CATEGORIES", Mon, 4 Oct 1993.
Regards, Marco Grandis
Dipartimento di Matematica, Universita di Genova, Via L.B.
Alberti 4, I - 16132 Genova, Italia
e-mail: grandis@dima.unige.it