From MAILER-DAEMON Sat Aug 23 10:19:01 2008 Date: 23 Aug 2008 10:19:01 -0300 From: Mail System Internal Data Subject: DON'T DELETE THIS MESSAGE -- FOLDER INTERNAL DATA Message-ID: <1219497541@mta.ca> X-IMAP: 1214916413 0000000031 Status: RO This text is part of the internal format of your mail folder, and is not a real message. It is created automatically by the mail system software. If deleted, important folder data will be lost, and it will be re-created with the data reset to initial values. From rrosebru@mta.ca Tue Jul 1 09:44:14 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Tue, 01 Jul 2008 09:44:14 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KDexC-00017I-Jr for categories-list@mta.ca; Tue, 01 Jul 2008 09:27:26 -0300 Mime-Version: 1.0 (Apple Message framework v624) Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit From: Paul Taylor Subject: categories: Abstract Stone Duality - introduction/survey papers Date: Tue, 1 Jul 2008 10:36:25 +0100 To: Categories list Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 1 People have been asking me for several years to write "introductions" to ASD, or to "write down all the axioms together". This was not possible while the core theory for locally compact spaces was still being investigated, but that process has essentially come to an end. There are now FOUR introduction/survey papers, aimed at different audiences, and all available from www.PaulTaylor.EU/ASD (lamcra) "A Lambda Calculus for Real Analysis" suitable for a general mathematical audience (intawi) "Interval Analysis Without Intervals" aimed at programmers of "exact real arithmetic" but not finished (dedras) "The Dedekind Reals in Abstract Stone Duality" (with Andrej Bauer) suitable for theoretical computer scientists (foufct) "Foundations for Computable Topology" I was invited to write this last paper for a volume on Foundations of Mathematics that is more inclined towards philosophy than technicalities and has contributions from categorists, set theorists and philosophers. My paper therefore begins with a discussion of the methodology behind ASD, and in particular the thesis that foundations can be devised FOR mathematics (rather than vice versa) by encapsulating headline theorems as universal properties and translating these into systems of introduction/elimination/beta/eta rules for new logical connectives. ASD abstracts Stone duality between algebra and topology by saying that the carriers of the algebras belong to the dual category of spaces, and formalises this as a monad. The topological meaning of Beck's characterisation of monadic adjunctions is that (certain) equalisers exist and carry the subspace topology in a canonical way. Several examples of this are given, in particular related to compactness of the real closed interval. Then the lambda calculus associated with the monad is described. The key object is the Sierpinski space Sigma. The Euclidean and Phoa principles are deduced from the property of classifying all, open or closed subsets. (A proof is included that Sierpinski classifies closed sublocales.) Conversely, the monadic and Euclidean principles make Sigma a dominance. Discrete, Hausdorff, compact and overt spaces are discussed. Set theory (ie the theory of discrete spaces) is used as a comparative case. Although most of the details of other arguments are only sketched, this paper includes the whole of the proof of the characterisation of elementary toposes using the ideas of ASD, without any mention of subobjects. Sketches of other parts of the theory are also given. The paper tries to tell the whole story of the development of ASD, from a foundational and empirical point of view, It is therefore of necessity a "broad brush" approach, as the material would easily fill a book. This paper is also meant to be complementary to the others listed above, so it says very little about the applications to elementary real analysis. It also says very little about the computational interpretation of ASD, but, at least as far as the real numbers are concerned, you can expect to hear more from Andrej and me on this subject in the future. If you would like to comment on "Foundations for Computable Topology", please do so before the end of July. Paul Taylor www.PaulTaylor.EU/ASD/foufct From rrosebru@mta.ca Tue Jul 1 12:35:00 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Tue, 01 Jul 2008 12:35:00 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KDhpJ-0002Hs-HP for categories-list@mta.ca; Tue, 01 Jul 2008 12:31:29 -0300 From: Gaucher Philippe To: categories@mta.ca Subject: categories: Preprint : Combinatorics of labelling in higher dimensional automata Date: Tue, 1 Jul 2008 14:49:24 +0200 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 2 Dear all, Here is a new preprint. Sincerely yours, pg. Title: Combinatorics of labelling in higher dimensional automata Abstract: The main idea for interpreting concurrent processes as labelled precubical sets is that a given set of n actions running concurrently must be assembled to a labelled n-cube, in exactly one way. The main ingredient is the non-functorial construction called labelled directed coskeleton. It is defined as a subobject of the labelled coskeleton, the latter coinciding in the unlabelled case with the right adjoint to the truncation functor. This non-functorial construction is necessary since the labelled coskeleton functor of the category of labelled precubical sets does not fulfil the above requirement. We prove in this paper that it is possible to force the labelled coskeleton functor to be well-behaved by working with labelled transverse symmetric precubical sets. Moreover, we prove that this solution is the only one. A transverse symmetric precubical set is a precubical set equipped with symmetry maps and with a new kind of degeneracy map called transverse degeneracy. Finally, we also prove that the two settings are equivalent from a directed algebraic topological viewpoint. To illustrate, a new semantics of CCS, equivalent to the old one, is given. Url: http://www.pps.jussieu.fr/~gaucher/symcub.ps http://www.pps.jussieu.fr/~gaucher/symcub.pdf Comments: 40 pages, comments welcome From rrosebru@mta.ca Wed Jul 2 09:27:22 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Wed, 02 Jul 2008 09:27:22 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KE1Jn-0003NW-9b for categories-list@mta.ca; Wed, 02 Jul 2008 09:20:15 -0300 Date: Tue, 1 Jul 2008 18:16:14 -0600 (MDT) Subject: categories: New technical report available From: mjhealy@ece.unm.edu To: categories@mta.ca MIME-Version: 1.0 Content-Type: text/plain;charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 3 A new University of New Mexico technical report is available on DSpace, ECE-TR-08-0010. It describes an experiment in cognitive psychology that tests a (mathematical) category-theoretic model of categorization by humans. The model is part of a comprehensive theoretical model of the declarative semantics of neural networks. The report can be obtained by going to DSpaceUNM, or directly to http://hdl.handle.net/1928/6724 . Questions and comments are welcome. Mike Healy Electrical and Computer Engineering University of New Mexico Albuquerque, NM USA Abstract Categorization and the judgement of similarity are fundamental in cognition. We propose that these and other activities are based upon an underlying structure of knowledge, or concept representation, in the brain. Further, we propose that this structure can be represented mathematically in a declarative form via category theory, the mathematica= l theory of structure. We test the resulting mathematical model in an experiment in which human subjects provide judgements of similarity for pairs of line drawings using a numerical scale to represent degrees of similarity. The resulting numerical similarities are compared with those derived from the category-theoretic model by comparing diagrams. The diagrams represent distributed concept structures underlying the line drawings. To compare with a more conventional analysis technique, we also compare the human judgements with those provided by a two-dimensional feature space model equipped with a distance metric for the line drawings= . The results are equally favorable for both models. Because of this and the putative explanatory power of the category-theoretic model, we propos= e that this model is worthy of further exploration as a mathematical model for cognitive science. Keywords categorization, (mathematical) category, cognition, colimit, concept, diagram, feature, morphism, similarity, theory From rrosebru@mta.ca Thu Jul 3 14:21:08 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Thu, 03 Jul 2008 14:21:08 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KESGu-0003ag-Cr for categories-list@mta.ca; Thu, 03 Jul 2008 14:07:04 -0300 Content-Type: text/plain; charset="iso-8859-15" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Date: Thu, 03 Jul 2008 09:53:07 +0200 From: =?iso-8859-15?q?Tom_Hirschowitz?= To: categories@mta.ca Subject: categories: Full_professor_position Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 4 Dear all, A full professor position will be available at Universit=E9 de = Savoie in Chamb=E9ry (France), from September 1, 2009. The new professor will be a member of the LIMD group = (Logique, Informatique et Math=E9matiques Discr=E8tes) and is = expected to do his research in proof theory in relation to = computer science, preferably in one or more of the following = areas: lambda-calculus, type theory, realizability, = denotational semantics (games, categories, ...), linear = logic, concurrency and mobility (process algebras, = bisimilarity, semantics, ...), mathematics of programming = languages (design, typing, compilation, ...), ... The LIMD group is a UMR (mixed CNRS-University research = unit), part of the mathematics laboratory (LAMA) at = Universit=E9 de Savoie. The LAMA (*) has presently 27 = permanent researchers in total; the LIMD group has 3 full = Professors, 4 "Maitre de conferences" and 2 CNRS = researchers. The position is made available by the = retirement of one of the professors. The teaching assignments are: mathematics and/or computer = science for students from L1 to M2 (in the new european = terminology). To get this position, it is necessary to - speak french fluently, and - have been accepted on the so-called "liste de = qualification". If you are not yet qualified, note that the = deadline for applying is usually around mid-october. For further details, please don't hesitate to contact me. Tom Hirschowitz (*) http://www.lama.univ-savoie.fr/ From rrosebru@mta.ca Sat Jul 5 09:41:59 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Sat, 05 Jul 2008 09:41:59 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KF6qe-00066C-4x for categories-list@mta.ca; Sat, 05 Jul 2008 09:26:40 -0300 Date: Fri, 4 Jul 2008 14:19:41 +0100 (BST) From: Marcelo Fiore To: categories@mta.ca Subject: categories: Three papers. MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 5 Dear All, this is to announce the three papers below available from the top of . Best regards, Marcelo. 1. M. Fiore and C.-K.Hur. On the construction of free algebras for equational systems. Submitted, 2008. Abstract. The purpose of this paper is threefold: to present a general abstract, yet practical, notion of equational system; to investigate and develop the finitary and transfinite construction of free algebras for equational systems; and to illustrate the use of equational systems as needed in modern applications. 2. M. Fiore and C.-K. Hur. Term Equational Systems and Logics. To appear in 24th Mathematical Foundations of Programming Semantics Conf. (MFPS XXIV), 2008. Abstract. We introduce an abstract general notion of system of equations between terms, called Term Equational System, and develop a sound logical deduction system, called Term Equational Logic, for equational reasoning. Further, we give an analysis of algebraic free constructions that together with an internal completeness result may be used to synthesise complete equational logics. Indeed, as an application, we synthesise a sound and complete nominal equational logic, called Synthetic Nominal Equational Logic, based on the category of Nominal Sets. Keywords. Equational systems, algebraic theories, free algebras, equational logic, soundness, completeness, Nominal Sets, Schanuel topos. 3. M. Fiore. Second-order and dependently-sorted abstract syntax. In Logic in Computer Science Conf. (LICS'08), pages 57-68. IEEE, Computer Society Press, 2008. Abstract. The paper develops a mathematical theory in the spirit of categorical algebra that provides a model theory for second-order and dependently-sorted syntax. The theory embodies notions such as alpha-equivalence, variable binding, capture-avoiding simultaneous substitution, term metavariable, meta-substitution, mono and multi sorting, and sort dependency. As a matter of illustration, a model is used to extract a second-order syntactic theory, which is thus guaranteed to be correct by construction. From rrosebru@mta.ca Sat Jul 5 09:41:59 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Sat, 05 Jul 2008 09:41:59 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KF6rD-000684-Hu for categories-list@mta.ca; Sat, 05 Jul 2008 09:27:15 -0300 From: Thorsten Altenkirch To: categories@mta.ca Content-Type: text/plain; charset=ISO-8859-1; format=flowed; delsp=yes Content-Transfer-Encoding: quoted-printable Mime-Version: 1.0 (Apple Message framework v924) Subject: categories: Lectureship at Nottingham Date: Fri, 4 Jul 2008 19:29:20 +0100 Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 6 Hi,=0A= =0A= we are advertising a lectureship in the Functional Programming Lab in=20=20= =0A= Nottingham. Note that the ad mentions "category theory" explicitely=20=20= =0A= and we'd like to see applications from people interested in=20=20=0A= applications of category theory in computer science. While the=20=20=0A= Functional Programming has been a research topic at Nottingham since=20=20= =0A= quite a while, the FP lab as an independent group was only created in=20=20= =0A= Autumn last year, see our new webpages=0A= http://sneezy.cs.nott.ac.uk/joomla/=0A= =0A= If you have any questions regarding the position (yes, it is a=20=20=0A= permanent faculty position, the teaching load is reasonable), the=20=20=0A= group or the location please don't hesitate to contact me. Application=20= =20=0A= is online and quite painless. Please remember: the deadline is *15=20=20=0A= August*.=0A= =0A= Cheers,=0A= Thorsten=0A= =0A= =0A= =0A= School of Computer Science=0A= Functional Programming Laboratory=0A= =0A= Lecturer in Computer Science=0A= =0A= Applications are invited for the above post in the School of Computer=20=20= =0A= Science. The successful candidate will be expected to participate in=20=20= =0A= the School's teaching activities and contribute to research in the=20=20=0A= recently formed Functional Programming Laboratory.=0A= =0A= Candidates must hold a PhD or equivalent in a relevant subject, have=20=20= =0A= an excellent publication record and the ability to teach at=20=20=0A= undergraduate and postgraduate level. It is desirable that candidates=20= =20=0A= have a track record of external research funding, collaboration across=20= =20=0A= disciplines, experience of different types of assessment and higher=20=20= =0A= education quality assurance. They should also have the ability to=20=20=0A= play a role in the routine running of the School of Computer Science.=0A= =0A= The Functional Programming Laboratory covers a broad range of topics=20=20= =0A= in the theory, practice, and implementation of functional programming=20=20= =0A= languages. Current interests include type theory, language design,=20=20= =0A= program semantics, program verification, modelling and simulation,=20=20=0A= category theory, programming tools, and quantum programming.=20=20=20=0A= Applications are welcome from any area that complements existing=20=20=0A= research strengths in the laboratory.=0A= =0A= Salary will be within the range =A330,912 - =A341,545 per annum, depending= =20=20=0A= on qualifications and experience (salary can progress to =A348,161 per=20= =20=0A= annum, subject to performance). This post is available immediately.=0A= =0A= Informal enquiries may be addressed to Dr T Altenkirch, tel: 0115 846=20=20= =0A= 6516, Email: Thorsten.Altenkirch@Nottingham.ac.uk or Dr G Hutton, tel:=20= =20=0A= 0115 951 4220, Email: Graham.M.Hutton@Nottingham.ac.uk. Further=20=20=0A= information about the School of Computer Science is available at: http://= www.nottingham.ac.uk/cs/=0A= =0A= For more details and/or to apply on-line please access: http://jobs.notting= ham.ac.uk/CJ24461S=20=0A= . If you are unable to apply on-line please contact the Human=20=20=0A= Resources Department, tel: 0115 951 3262 or fax: 0115 951 5205.=20=20=20=0A= Please quote ref. CJ/24461S. Closing date: 15 August 2008. Interview=20= =20=0A= date: 17 September 2008.=0A= =0A= =0A= This message has been checked for viruses but the contents of an attachment= =0A= may still contain software viruses, which could damage your computer system:= =0A= you are advised to perform your own checks. Email communications with the= =0A= University of Nottingham may be monitored as permitted by UK legislation.= =0A= =0A= From rrosebru@mta.ca Tue Jul 8 10:45:41 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Tue, 08 Jul 2008 10:45:41 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KGDDv-0003DC-9m for categories-list@mta.ca; Tue, 08 Jul 2008 10:27:15 -0300 Date: Mon, 7 Jul 2008 14:35:11 -0700 From: "Meredith Gregory" To: categories@mta.ca Subject: categories: abstract combinatory logic? MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 7 All, i recently ran across a use of fold (in the functional programming sense) where i wanted to solve for the accumulator type. i realized that something in the neighborhood of a combinatory logic would be a minimal solution. This got me thinking... there are various versions of combinators for the \lambda-calculus and there's Haghverdi's combinators for linear lambda and there are Yoshida's combinators for Milner's \pi-calculus. The first two will work in the setting i encountered, the latter will not because -- in addition to (parallel) composition -- Yoshida's combinators require a new and replication operator. So, i'm wondering if anyone has given an abstract characterization of a combinatory logic/algebra? If so, does anyone have a reference? Best wishes, --greg -- L.G. Meredith Managing Partner Biosimilarity LLC 806 55th St NE Seattle, WA 98105 +1 206.650.3740 http://biosimilarity.blogspot.com From rrosebru@mta.ca Wed Jul 9 20:05:58 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Wed, 09 Jul 2008 20:05:58 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KGiTw-000709-CO for categories-list@mta.ca; Wed, 09 Jul 2008 19:49:52 -0300 Date: Wed, 09 Jul 2008 09:21:18 -0400 From: Walter Tholen MIME-Version: 1.0 To: categories@mta.ca Subject: categories: HB, and "Thank you" Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: RO X-Status: X-Keywords: X-UID: 8 [Longish note from moderator: The gracious words below are much appreciated, sincere thanks to Walter. I'm reluctantly following the injunction at the bottom of his message. It gives me the chance to write that the "categories" and TAC jobs are done gladly, and indeed without altruism - any service to the category theory community is absolutely its own reward. It's always a privilege, and the very best of intellectual fun and challenge, to be associated with category theorists and category theory. As to TAC especially, this is also a chance for my thanks, on behalf of our community, to the hard-working TAC Editors (none more so than Walter) and their referees. Special thanks also go to Michael Barr for keeping TAC looking good. Please don't reply to the list on this off-topic item. Walter has written very kindly for everyone who might do so. ] Hi Bob: Bill Lawvere already mentioned your big birthday in Calais, but not everybody on the "categories" list may be aware that today (July 9, if I remember correctly) is the actual day when you get elevated into some already heavily populated grey zone: congratulations! Somewhat more importantly, I would like to take the occasion to thank you for the immense service to our community that you have been providing for so many years now, by initiating and running "categories" and "TAC". In fact, I believe that both ventures have been critical in building a sense of community that becomes most apparent at the CT meetings. Your cool and consistently measured style in running the two enterprises has won you everybody's respect and gratitude, I think. Last, but not least, let me take this occasion to thank you, Maria Manuel Clementino, George Janelidze and Jiri Rosicky for editing a special volume in TAC marking my own entry into that grey zone that you are reaching today. As mentioned to you earlier, it's obviously an undeserved honour which I nevertheless enjoy tremendously. Of course, I am especially indebted to the authors who have contributed to the volume. Thanks again, and best wishes, Walter. Note to Moderator: Don't even think of suppressing THIS message from the list! From rrosebru@mta.ca Thu Jul 10 15:58:09 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Thu, 10 Jul 2008 15:58:09 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KH1IS-0007EA-SC for categories-list@mta.ca; Thu, 10 Jul 2008 15:55:16 -0300 From: Pedro Resende To: Categories list Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit Subject: categories: New Research Positions Mime-Version: 1.0 (Apple Message framework v926) Date: Thu, 10 Jul 2008 17:01:07 +0100 Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 9 The announcement below may be of interest to some readers of the categories list. Please forward it to anyone you may think could be interested in applying. I apologize in advance for any duplicate copies of this message. Best regards, Pedro. ##### The Center for Mathematical Analysis, Geometry and Dynamical Systems of IST has opened 3 research positions in Mathematics in one of the areas in which the faculty of the Center is currently active, privileging the following: - Differential Equations and Dynamical Systems; - Geometry and Topology (including String Theory and Mathematical- Physics). The successful candidates will receive a salary in accordance with the university regulations for a junior researcher (Investigador Auxiliar). The contract offered will have duration of up to 5 years, renewed yearly based on mutual agreement. The annual gross income, before taxes, will be approximately 3000 Euros x 14 months. APPLICANTS Applicants should have obtained a PhD in Mathematics, or in a related area relevant to the scientific interests of the faculty of the Center. Candidates should have a high quality research record and at least 3 years of post-doctoral research experience. The successful candidates are expected to do research in the areas listed above. HOW TO APPLY By email to the President of the Center at camgsd(AT)math.ist.utl.pt with PDF files of: - Identification of the candidate - Curriculum Vitae/resume - Letters of Reference (sent directly by the undersigners) - Description of research project (of no more than 1000 words) Reprints, preprints and/or a dissertation abstract may also be sent at discretion. Deadline: September 10, 2008. More information: http://camgsd.math.ist.utl.pt/ From rrosebru@mta.ca Mon Jul 14 10:10:02 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Mon, 14 Jul 2008 10:10:02 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KINm3-000125-Ac for categories-list@mta.ca; Mon, 14 Jul 2008 10:07:27 -0300 Date: Sun, 13 Jul 2008 23:05:55 -0300 From: "Eduardo Ochs" To: categories@mta.ca Subject: categories: A question about filter-powers (and infinitesimals) MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 10 Hello list, I am looking for references on the following facts about interpreting some sentences involving infinitesimals in filter-powers instead of in ultrapowers... Notation: \I is an index set; \F is a filter on \I; \U is an ultrafilter on \I, possibly extending \F; if X is a topological space and x is a point of X, then \V_x is the filter of neighborhoods of x in X; Set^\F is a shorthand for the filter-power (Set^\I)/\F; Set^\U is a shorthand for the ultrapower (Set^\I)/\U; Terminology: Set is the "standard universe"; Set^\U is the "non-standard universe"; Set^\F is the "semi-standard universe"; points of Set^\I are called "sequences", or "pre-hyperpoints"; points of Set^\F or Set^\U are called "hyperpoints". Well, the facts. Here they are: (1) For any (standard) function f:X->Y from a topological space to another, and for any standard point x in X, the following three statements are equivalent: (a) f is continuous at x; (b) for all choices of a triple (\I, \F, x_1), where \I is an index set, \F is a filter on \I, and x_1 is a hyperpoint infinitely close to x, then f(x_1) is infinitely close to f(x); (c) for the "natural infinitesimal" (\I, \F, x_1) := (X, \V_x, id), the hyperpoint f(x_1) is infinitely close to f(x). (2) Any filter-infinitesimal (\I, \F, x_1) infinitely close to x factors through the natural infinitesimal (X, \V_x, id) in a unique way. (3) We can use these ideas to lift proofs done in a certain "strictly calculational fragment" of the language of non-standard analysis to constructions done in a filter-power; and then, if we replace the free variables that stand for infinitesimals in our formulas by natural infinitesimals, we get (by (c)<=>(a) in (1)) a translation of our proof with infinitesimals to a standard proof, in terms of limits and continuity. On the one hand, I have never seen anything published about filter-infinitesimals, and it took me a long time to find the right formulations for this... on the other hand, ideas similar to these seem to be implicit in many places (see the last sections of the PDF). However, my guess is that at least parts of (3) are new. There are more details at: http://angg.twu.net/LATEX/2008filterp.pdf http://angg.twu.net/math-b.html Thanks in advance for any pointers, comments, etc... Questions welcome, of course. Cheers, Eduardo Ochs eduardoochs@gmail.com P.S.: the diagrams in the PDF were made with: http://angg.twu.net/dednat4.html From rrosebru@mta.ca Thu Jul 17 12:48:56 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Thu, 17 Jul 2008 12:48:56 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KJVgO-0000ph-Oz for categories-list@mta.ca; Thu, 17 Jul 2008 12:46:16 -0300 Date: Thu, 17 Jul 2008 10:35:20 +0200 (CEST) From: Johannes Huebschmann To: categories@mta.ca Subject: categories: Query MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 11 Dear All Given a Lie group G and a G-representation V, according to Hochschild-Mostow, the ordinary Eilenberg-Mac Lane construction, suitably interpreted in terms of smooth functions, yields a differentiably injective resolution of V over G. More precisely, the Eilenberg-Mac Lane construction (dual bar construction) arises here as the differentiable cosimplicial G-module having, in degree p, the space of smooth V-valued maps on a product of p+1 copies of G, with the ordinary coface and codegeneracy operators. Suppose now that G is connected and finite-dimensional and let K be a maximal compact subgroup. Hochschild-Mostow have also shown that the V-valued differential forms on G/K then yield an injective resolution of V over G as well. This kind of construction actually goes back to van Est. The standard procedure yields comparison maps between the two resolutions. In degree zero the comparison is, of course, achieved by the obvious map from C^{\infty}(G/K,V) to C^{\infty}(G,V) induced by the projection from G to G/K and by the obvious map from C^{\infty}(G,V) to C^{\infty}(G/K,V) induced by integration over K. Does anybody know whether, in the literature, the constituents of a comparison map in higher degrees have been spelled out explicitly somewhere? Many thanks in advance Best regards Johannes HUEBSCHMANN Johannes Professeur de Mathematiques USTL, UFR de Mathematiques UMR 8524 Laboratoire Paul Painleve F-59 655 Villeneuve d'Ascq Cedex France http://math.univ-lille1.fr/~huebschm TEL. (33) 3 20 43 41 97 (33) 3 20 43 42 33 (secretariat) (33) 3 20 43 48 50 (secretariat) Fax (33) 3 20 43 43 02 e-mail Johannes.Huebschmann@math.univ-lille1.fr From rrosebru@mta.ca Sat Jul 19 11:26:27 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Sat, 19 Jul 2008 11:26:27 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KKDLd-0001xf-QV for categories-list@mta.ca; Sat, 19 Jul 2008 11:23:45 -0300 To: categories@mta.ca Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (Apple Message framework v926) Subject: categories: DOMAINS IX [ Call for Participation ] Date: Thu, 17 Jul 2008 20:19:32 +0100 From: Bernhard Reus Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 12 ------------------------------------------------------------------------------------- C A L L F O R P A R T I C I P A T I O N Workshop DOMAINS IX http://www.informatics.sussex.ac.uk/events/domains9/ University of Sussex, Brighton, 22-24 September 2008 Sponsored by the EPSRC and the London Mathematical Society -------------------------------------------------------------------------------------- INTRODUCTION The Workshop on Domains is aimed at computer scientists and mathematicians alike who share an interest in the mathematical foundations of computation. The workshop will focus on domains, their applications and related topics. INVITED SPEAKERS (confirmed) Jean Goubault-Larrecq LSV/ENS Cachan & CNRS Martin Hyland Cambridge University Klaus Keimel TU Darmstadt John Longley University of Edinburgh Andrew Pitts Cambridge University Gordon Plotkin University of Edinburgh/Stanford Dana Scott CMU/Berkely CONTRIBUTED TALKS A list of contributed talks with abstracts is available from the workshop page (see URL above) that contains also more information about the scope of the meeting. FORMAT The emphasis is on the exchange of ideas between participants similar in style to Dagstuhl seminars. In particular, talks on subjects presented at other conferences and workshops are acceptable. VENUE The workshop will take place at the University of Sussex. It will commence at 9:30am on Monday morning and close around 4pm on Wednesday afternoon. ACCOMMODATION Bed & breakfast on campus in single rooms with en suite bathroom (standard) is available at 45 pounds per night in our brand new halls of residence or at a more economical 30.50 pound with shared facilities (budget). Lunch is included in the registration fee. There will be no organized evening meals except the Workshop dinner. REGISTRATION Registration is now open. Please download the registration form from the workshop web pages at: EARLY REGISTRATION DEADLINE is *** AUGUST 7th *** at the reduced registration fee of 40 pounds. Please register as early as possible to secure a room at the above mentioned rates on campus. You can still register after August 7th at a fee of 70 pounds but in this case availability of rooms is not guaranteed and you may need to find accommodation yourself which can be quite tricky in Brighton. Note that the registration fee includes all lunches (Mo-Wed). Lunches will take place in a building adjacent to the lecture theatre. To register, please print the form, filling in all relevant fields including your room booking and credit card details. Sign the form and fax it (or send via surface mail) to Mrs Elizabeth Marriott Fax: +44 (0)1273 877873 Department of Informatics University of Sussex Brighton BN1 9QJ UK Successful registration will be confirmed by email. Registered participants will then receive further instructions about their accommodation, check in, and the exact location of the meeting They will get a receipt at the meeting. You are expected to pay by credit card. If this is impossible or if you have further questions regarding registration please contact Elizabeth Marriott at E.Marriott@sussex.ac.uk or check out the workshop website. GRANTS FOR PHD STUDENTS or PARTICIPANTS FROM Scheme 5 COUNTRIES PhD students with a grant from the EPSRC can get free accommodation and registration for DOMAINS IX thanks to support from the EPSRC. Mathematicians from former Soviet states or Africa (Scheme 5 countries) can also get financial support provided by the LMS. If you think you are eligible for any of the above please contact the PC as soon as possible at the workshop email address domains9@sussex.ac.uk LATE SUBMISSION OF ABSTRACTS If you would like to give a talk but have not submitted in time you can still send a one-page abstract to the workshop email address but please be aware that at this late stage any incoming abstracts are strictly dealt with in order of arrival and compete for a quite small number of remaining slots. PROGRAMME COMMITTEE Martin Escardo University of Birmingham Achim Jung (Co-Chair) University of Birmingham Klaus Keimel (Co-Chair) Darmstadt University Bernhard Reus (Co-Chair) University of Sussex Thomas Streicher Darmstadt University ORGANIZATION COMMITTEE Bernhard Reus University of Sussex PUBLICATION We plan to publish proceedings of the workshop in a journal. There will be a call for papers after the workshop. The papers will be refereed according to normal publication standards. URL http://www.informatics.sussex.ac.uk/events/domains9/ From rrosebru@mta.ca Sat Jul 19 11:26:27 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Sat, 19 Jul 2008 11:26:27 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KKDMu-00020K-JY for categories-list@mta.ca; Sat, 19 Jul 2008 11:25:04 -0300 Date: Fri, 18 Jul 2008 16:09:46 +0200 From: Ugo Dal Lago MIME-Version: 1.0 To: undisclosed-recipients:; Subject: categories: CSL 2008: Call for Participation Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 13 [Apologies for Multiple Copies] ******************************************** * 17th EACSL Annual Conference on * * * * COMPUTER SCIENCE LOGIC * * * * September 15-19, 2008 * * Bertinoro, ITALY * ******************************************** INVITED SPEAKERS Luca Cardelli, Microsoft Research, Cambridge Pierre Louis Curien, PPS, Universite' Paris VII, Paris Jean-Pierre Jouannaud, Ecole Polytechnique, Palaiseau Wolfgang Thomas, RWTH, Aachen ACCEPTED PAPERS http://csl2008.cs.unibo.it/accepted.html PROGRAM http://csl2008.cs.unibo.it/program.html http://csl2008.cs.unibo.it/preliminaryprogram.pdf REGISTRATION INFORMATION http://csl2008.cs.unibo.it/registration.html * Early registration deadline: August 16th, 2008 * VENUE http://www.centrocongressibertinoro.it/inglese/centro_universitario.htm MAKOWSKY SYMPOSIUM http://csl2008.cs.unibo.it/bridging.html From rrosebru@mta.ca Sat Jul 19 11:26:29 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Sat, 19 Jul 2008 11:26:29 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KKDOA-00023W-7m for categories-list@mta.ca; Sat, 19 Jul 2008 11:26:22 -0300 Subject: categories: Categories in Algebra, Geometry and Logic: First Announcement From: Tim Van der Linden To: categories@mta.ca Content-Type: text/plain; charset=UTF-8 Date: Fri, 18 Jul 2008 18:01:19 +0200 Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 14 As already informally announced at CT08, we are happy to invite you to Br= ussels next October for a weekend meeting in honour of Francis Borceux and Dominique = Bourn on the=20 occasion of their 60th birthdays. =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D Categories in Algebra, Geometry and Logic =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D Royal Flemish Academy of Belgium Hertogsstraat 1 Rue Ducale 1000 Brussels Belgium 10, 11 October 2008 Information about registration, accommodation, deadlines is now available= on the web page http://www.math.ua.ac.be/bbdays/ Keynote Speakers: ----------------- J. Ad=C3=A1mek (Braunschweig) J. B=C3=A9nabou (Paris) M. M. Clementino (Coimbra) A. Ehresmann (Amiens) G. Janelidze (Cape Town) P. Johnstone (Cambridge) F. W. Lawvere (Buffalo) J. P=C3=A9non (Paris) J. Rosick=C3=BD (Brno) W. Tholen (Toronto) Shorter Communications by: -------------------------- S. Caenepeel (Brussel) Z. Janelidze (Cape Town) S. Mantovani (Milano) D. Rodelo (Faro) I. Stubbe (Antwerpen) T. Van der Linden (Coimbra, Brussel) Organizing Committee: --------------------- Marino Gran (ULCO, Calais), Rudger Kieboom (VUB, Brussel), Isar Stubbe (UA, Antwerpen), Tim Van der Linden (VUB, Brussel), Enrico Vitale (UCL, Louvain-La-Neuve). =EF=BB=BFPlease circulate this message amongst all interested colleagues. From rrosebru@mta.ca Sat Jul 19 11:27:35 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Sat, 19 Jul 2008 11:27:35 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KKDPD-000271-US for categories-list@mta.ca; Sat, 19 Jul 2008 11:27:28 -0300 Date: Fri, 18 Jul 2008 16:31:58 +0200 From: Jaap van Oosten User-Agent: Thunderbird 1.5.0.10 (X11/20070304) MIME-Version: 1.0 To: categories@mta.ca Subject: categories: New Book: Jaap van Oosten - Realizability Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 15 The following book appeared in April this year: Jaap van Oosten - Realizability: an Introduction to its Categorical Side Studies in Logic 152, Elsevier This book is a monograph about the effective topos and related toposes. The book is intended to provide advanced undergraduate students and Ph.D. students with a concise introduction to the effective topos. Contains introductions to partial combinatory algebras, tripos theory, construction of the effective topos. Synthesizes the existing literature, making a lot of material accessible to all readers. Many applications to recursive analysis, intuitionistic set theory, synthetic domain theory. Reviews abstract aspects of the effective topos construction. Variations are also developed, such as Lifschitz realizability, Modified realizability, Kleene-Vesley realizability. For Preface, Introduction and Table of Contents see: http://www.math.uu.nl/people/jvoosten/boekbegin.pdf From rrosebru@mta.ca Sun Jul 20 12:40:51 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Sun, 20 Jul 2008 12:40:51 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KKaz3-000053-Tq for categories-list@mta.ca; Sun, 20 Jul 2008 12:38:01 -0300 Date: Sat, 19 Jul 2008 12:55:59 -0500 (Central Daylight Time) From: Eugenia Cheng To: categories@mta.ca Subject: categories: Martin Hyland and Peter Johnstone birthday PSSL MIME-Version: 1.0 Content-Type: TEXT/PLAIN; format=flowed; charset=US-ASCII Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 16 Dear All, Following the informal announcement at CT08, We are very pleased to announce a conference to celebrate the 60th birthdays of Martin Hyland and Peter Johnstone. How: PSSL Where: Cambridge When: weekend of 4-5 April 2009 The conference will be generously supported by the Morgan Phoa Family Fund and the Department of Pure Mathematics and Mathematical Statistics of Cambridge University. We are making this preliminary announcement well in advance, as We hope that very many people will be able to join us and contribute talks for this event. The website for the conference is at http://cheng.staff.shef.ac.uk/pssl88/ If you have any questions please feel free to contact Eugenia Cheng at e.cheng@sheffield.ac.uk We hope to see you there, Eugenia Cheng Andy Pitts (organisers) From rrosebru@mta.ca Tue Jul 22 10:12:29 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Tue, 22 Jul 2008 10:12:29 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KLHcb-00067z-9C for categories-list@mta.ca; Tue, 22 Jul 2008 10:09:41 -0300 Date: Mon, 21 Jul 2008 20:44:12 -0300 From: Walter Carnielli MIME-Version: 1.0 To: categories@mta.ca Subject: categories: 3rd Edition of "Computability: Computable Functions, Logic, and the Foundations of Mathematics" (Epstein & Carnielli) Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: quoted-printable Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 17 Dear Colleagues: we are happy to announce the 2008 edition of "Computability: Computable Functions, Logic, and the Foundations of=20 Mathematics" Authors: Richard L. Epstein and Walter Carnielli Publisher: Advanced Reasoning Forum, 2008 *3rd. Edition* " Now in a new edition --the classic presentation of the theory of computable functions in the context of the foundations of mathematics. Part I motivates the study of computability with discussions and readings about the crisis in the foundations of mathematics in the early 20th century while presenting the basic ideas of whole number, function, proof, and real number. Part II starts with readings from Turing and Post leading to the formal theory of recursive functions. Part III presents sufficient formal logic to give a full development of G=F6del's incompleteness theorems. Part IV considers the significance of the technical work with a discussion of Church's Thesis and readings on the foundations of mathematics. This new edition contains the timeline 'Computability and Undecidability' as well as the essay 'On Mathematics'. " Available from Powell's Books: Adobe Reader e-book format (Windows and Macintosh compatible): http://www.powells.com/cgi-bin/biblio?inkey=3D91-9780981550732-0 Hardcover: http://www.powells.com/biblio?isbn=3D978-0-9815507-2-5 Also available from Barnes & Noble. Prices are very reasonable, specially for the e-book verion (around $15.0= 0) --=20 +++++++++++++++++++++++++++++++++++++++++++++++++ Walter Carnielli Centre for Logic, Epistemology and the History of Science =96 CLE State University of Campinas =96UNICAMP P.O. Box 6133 13083-970 Campinas -SP, Brazil Phone: (+55) (19) 3788-6519 Fax: (+55) (19) 3289-3269 e-mail: carniell@cle.unicamp.br Website: http://www.cle.unicamp.br/prof/carnielli=20 From rrosebru@mta.ca Tue Jul 22 11:39:50 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Tue, 22 Jul 2008 11:39:50 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KLJ0c-0005ib-1W for categories-list@mta.ca; Tue, 22 Jul 2008 11:38:34 -0300 Mime-Version: 1.0 (Apple Message framework v624) Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit From: Paul Taylor Subject: categories: products preserve epis of locales Date: Tue, 22 Jul 2008 14:35:19 +0100 To: Categories list Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 18 Where can I find a published proof that if X --->> Y is a (not necessarily regular) epi of locales then so is X x Z --->> Y x Z for any locale Z? NB (I know that) this is not true for general pullbacks of locales! Ideally, I'd like to cite a textbook-style account that begins by characterising epis and regular monos as idempotent adjunctions, saying that they form a factorisation system, and describes the product of locales fairly explicitly. Paul From rrosebru@mta.ca Wed Jul 23 10:17:47 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Wed, 23 Jul 2008 10:17:47 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KLeBB-0007Pg-P9 for categories-list@mta.ca; Wed, 23 Jul 2008 10:14:53 -0300 Date: Wed, 23 Jul 2008 8:03:15 -0300 (ADT) From: Bob Rosebrugh To: categories Subject: categories: list interruption MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 19 The categories moderator will be mostly out of email contact for the period July 25-August 4, 2008. Postings submitted to categories during that period will be distributed by August 5. Best wishes, Bob Rosebrugh From rrosebru@mta.ca Wed Jul 23 10:17:48 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Wed, 23 Jul 2008 10:17:48 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KLeBx-0007TX-Pk for categories-list@mta.ca; Wed, 23 Jul 2008 10:15:41 -0300 To: categories@mta.ca Subject: categories: PhD Positions in Secure Software and Languages Date: Tue, 22 Jul 2008 17:08:36 +0200 (CEST) From: David.Clarke@cwi.nl Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 20 [Please forward this announcement to interested students] Two PhD Positions in Secure Software and Languages Department of Computer Science Katholieke Universiteit Leuven, Belgium Applications are invited for two PhD positions within the DistriNet Research Group at the Katholieke Universiteit Leuven, Belgium. The research will be conducted under the supervision of David Clarke. * Research topics: These positions are devoted to research on secure software and languages, including, but not limited to: * modelling highly adaptable trustworthy systems * types and models for software families * logic and type systems for security; ownership types; pluggable types * programming languages for secure software * Profile & skills - Clear interest in and knowledge of the subject, based on education, work or research experience - Masters in Computer Science or Informatics - Team player; capability to work in an international research team - Proficiency in English and excellent communication skills, both oral and written - Prior knowledge in the areas of type systems, security, programming languages and/or formal methods is an advantage. * About DistriNet The "Distributed systems and computer Networks=E2" (DistriNet) research group was founded in 1984 as part of the Department of Computer Science at the K.U.Leuven. DistriNet's research focus and scope is twofold: distributed software=E2 and secure software. The group works on a wide range of topics including computer networks, middleware, internet architectures, network and software security, embedded systems and multi-agent systems. DistriNet's research is generally application driven and often conducted in collaboration with industry partners. Currently DistriNet counts 60 members (8 professors, 12 post-docs and 45 junior researchers) and participates in about 30 national and international research projects. The annual budget amounts to approximately 5MEuro. More information on projects and publications can be found on the DistriNet web pages: http://distrinet.cs.kuleuven.be/ * About Leuven Lively Leuven is a picturesque and upbeat Flemish city, just 25km from Brussels, and within 3 hours of major European centres such as Antwerp, Amsterdam, London and Paris. Leuven is shaped by its healthy student population - some 25,000 of them - more than a quarter of the town's population. * Further Information and Application Procedure Requests for further information and other informal enquiries can be sent to: Dr. David Clarke David.Clarke at cs.kuleuven.be Those interested in the position are asked to send e-mail to the address given above. Full Details of the application process are available upon request, but an application will include: 1. A cover letter stating the applicant's interest in the project. 2. A full curriculum vitae, including an abstract of the applicant's master's thesis and the name of their supervisor. 3. Letters of recommendation or references from at least two scientific staff members. (Letters of recommendation should either be included along with the application, or should arrive separately promptly.) 4. A completed application for postgraduate study at the K.U.Leuven. Applications and instructions are available at http://www.kuleuven.be/phd/ Applications will be considered until the position is filled, but those received on or before 15 August 2008 will have priority. The PhD positions are for 4 years. The start date is negotiable, 1 October 2008 at the earliest. From rrosebru@mta.ca Wed Jul 23 22:05:52 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Wed, 23 Jul 2008 22:05:52 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KLpG5-0005Ay-2e for categories-list@mta.ca; Wed, 23 Jul 2008 22:04:41 -0300 From: "George Janelidze" To: "categories" Subject: categories: CT2009 and Max Kelly Volume of APCS Date: Thu, 24 Jul 2008 00:57:54 +0200 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: RO X-Status: X-Keywords: X-UID: 21 Dear Colleagues, Concerning Annual International Conference in Category Theory - CT2009 - in Cape Town: This is a very preliminary announcement (known to the participants of CT2008 in Calais): The venue of CT2009 will be the Upper Campus of the University of Cape Town. Opening of the Conference: Monday, 29 June 2009. The last talk will be given before lunch on Saturday, 4 July 2009. More information will follow in further announcements, first of which will be sent in August 2008. Concerning Max Kelly Volume of APCS: Some of you told me in Calais, that they could submit a paper if the deadline were a bit later than July 1. Please either submit your papers before August 1, or let me know that you need a few more days. George Janelidze From rrosebru@mta.ca Thu Jul 24 10:20:00 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Thu, 24 Jul 2008 10:20:00 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KM0hC-0000eZ-So for categories-list@mta.ca; Thu, 24 Jul 2008 10:17:26 -0300 To: categories@mta.ca Subject: categories: Categories, Logic and Foundations of Physics, August 23-24, Oxford University MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: cat-dist@mta.ca Precedence: bulk Message-Id: From: cat-dist@mta.ca Date: Thu, 24 Jul 2008 10:17:26 -0300 Status: O X-Status: X-Keywords: X-UID: 22 Dear All, The next workshop on "Categories, Logic and Foundations of Physics" will take place at Oxford University, August 23-24. Programs and videos of previous workshops are available: * http://categorieslogicphysics.wikidot.com/ We have several confirmed speakers: * Steve Vickers (Birmingham, Computer Science) http://www.cs.bham.ac.uk/~sjv/ * Keith Hannabus (Oxford, Mathematics) http://users.ox.ac.uk/~kch/ * John Barrett (Nothingham, Mathematics) http://www.maths.nottingham.ac.uk/personal/jwb/ * Chris Fewster (York, Mathematics) http://www-users.york.ac.uk/~cjf3/ * Simon Perdrix (Oxford, Computer Science) http://www.comlab.ox.ac.uk/people/Simon.Perdrix/ * Mehrnoosh Sadrzadeh (Paris VII, PPS) http://www.pps.jussieu.fr/~mehrs/ but are expected to have several more. It was requested by the audience at the last workshop to provide tutorials, namely quantum theory for mathematicians and category theory for physicists. At this workshop we will provide the first: * Tutorials on quantum theory for mathematicians On Saturday morning and early afternoon. Travel and hotel information will be made available at the website very soon. As before, for reasons of logistics, could you please let us know if you intend to attend. Best wishes, Bob Coecke and Andreas Doering. From rrosebru@mta.ca Thu Jul 24 19:34:50 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Thu, 24 Jul 2008 19:34:50 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KM9N6-0005h9-0s for categories-list@mta.ca; Thu, 24 Jul 2008 19:33:16 -0300 From: To: carlos.martin@urv.cat Date: Thu, 24 Jul 2008 15:43:41 +0200 MIME-Version: 1.0 Subject: categories: LATA 2009: call for papers Content-Type: text/plain; charset=windows-1252 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 23 Apologies for multiple posting! Please=2C forward the announcement to whoever may be interested in it=2E= Thanks=2E ********************************************************************* Call for Papers 3rd INTERNATIONAL CONFERENCE ON LANGUAGE AND AUTOMATA THEORY AND APPLICA= TIONS (LATA 2009) Tarragona=2C Spain=2C April 2-8=2C 2009 http=3A//grammars=2Egrlmc=2Ecom/LATA2009/ ********************************************************************* AIMS=3A LATA is a yearly conference in theoretical computer science and its appl= ications=2E As linked to the International PhD School in Formal Language= s and Applications that was developed at the host institute in the perio= d 2002-2006=2C LATA 2009 will reserve significant room for young scholar= s at the beginning of their career=2E It will aim at attracting contribu= tions from both classical theory fields and application areas (bioinform= atics=2C systems biology=2C language technology=2C artificial intelligen= ce=2C etc=2E)=2E SCOPE=3A Topics of either theoretical or applied interest include=2C but are not = limited to=3A - algebraic language theory - algorithms on automata and words - automata and logic - automata for system analysis and programme verification - automata=2C concurrency and Petri nets - biomolecular nanotechnology - cellular automata - circuits and networks - combinatorics on words - computability - computational=2C descriptional=2C communication and parameterized comp= lexity - data and image compression - decidability questions on words and languages - digital libraries - DNA and other models of bio-inspired computing - document engineering - extended automata - foundations of finite state technology - fuzzy and rough languages - grammars (Chomsky hierarchy=2C contextual=2C multidimensional=2C unifi= cation=2C categorial=2C etc=2E) - grammars and automata architectures - grammatical inference and algorithmic learning - graphs and graph transformation - language varieties and semigroups - language-based cryptography - language-theoretic foundations of natural language processing=2C artif= icial intelligence and artificial life - mathematical evolutionary genomics - parsing - patterns and codes - power series - quantum=2C chemical and optical computing - regulated rewriting - string and combinatorial issues in computational biology and bioinform= atics - symbolic dynamics - symbolic neural networks - term rewriting - text algorithms - text retrieval=2C pattern matching and pattern recognition - transducers - trees=2C tree languages and tree machines - weighted machines STRUCTURE=3A LATA 2009 will consist of=3A - 3 invited talks (to be announced in the second call for papers) - 2 invited tutorials (to be announced in the second call for papers) - refereed contributions - open sessions for discussion in specific subfields or on professional = issues (if requested by the participants) PROGRAMME COMMITTEE=3A Parosh Abdulla (Uppsala) Stefania Bandini (Milano) Stephen Bloom (Hoboken) John Brzozowski (Waterloo) Maxime Crochemore (London) Juergen Dassow (Magdeburg) Michael Domaratzki (Winnipeg) Henning Fernau (Trier) Rusins Freivalds (Riga) Vesa Halava (Turku) Juraj Hromkovic (Zurich) Lucian Ilie (London=2C Canada) Kazuo Iwama (Kyoto) Aravind Joshi (Philadelphia) Juhani Karhumaki (Turku) Jarkko Kari (Turku) Claude Kirchner (Bordeaux) Maciej Koutny (Newcastle) Kamala Krithivasan (Chennai) Martin Kutrib (Giessen) Andrzej Lingas (Lund) Aldo de Luca (Napoli) Rupak Majumdar (Los Angeles) Carlos Martin-Vide (Tarragona =26 Brussels=2C chair) Joachim Niehren (Villeneuve d=27Ascq) Antonio Restivo (Palermo) Joerg Rothe (Duesseldorf) Wojciech Rytter (Warsaw) Philippe Schnoebelen (Cachan) Thomas Schwentick (Dortmund) Helmut Seidl (Muenchen) Alan Selman (Buffalo) Jeffrey Shallit (Waterloo) Frank Stephan (Singapore) ORGANIZING COMMITTEE=3A Madalina Barbaiani Gemma Bel-Enguix Cristina Bibire Adrian-Horia Dediu Szilard-Zsolt Fazekas Alexander Krassovitskiy Guangwu Liu Carlos Martin-Vide (chair) Robert Mercas Catalin-Ionut Tirnauca Bianca Truthe Sherzod Turaev Florentina-Lilica Voicu SUBMISSIONS=3A Authors are invited to submit papers presenting original and unpublished= research=2E Papers should not exceed 12 single-spaced pages and should = be formatted according to the standard format for Springer Verlag=27s LN= CS series (see http=3A//www=2Espringer=2Ecom/computer/lncs/lncs+authors=3F= SGWID=3D0-40209-0-0-0)=2E Submissions have to be uploaded at=3A http=3A//www=2Eeasychair=2Eorg/conferences/=3Fconf=3Dlata2009 PUBLICATION=3A A volume of proceedings published by Springer in the LNCS series will be= available by the time of the conference=2E A refereed volume of extende= d versions of selected papers will be published after it as a special is= sue of a major journal=2E (This was Information and Computation for LATA= 2007 and LATA 2008=2E) REGISTRATION=3A The period for registration will be open since September 1=2C 2008 to Ap= ril 2=2C 2009=2E The registration form can be found at the website of th= e conference=3A http=3A//grammars=2Egrlmc=2Ecom/LATA2009/ Early registration fees=3A 450 euros Early registration fees (PhD students)=3A 225 euros Registration fees=3A 540 euros Registration fees (PhD students)=3A 270 euros At least one author per paper should register=2E Papers that do not have= a registered author by December 31=2C 2008 will be excluded from the pr= oceedings=2E Fees comprise free access to all sessions=2C one copy of the proceedings= volume=2C and coffee breaks=2E For the participation in the full-day ex= cursion and conference lunch on Sunday April 5=2C the amount of 70 euros= is to be added to the fees above=3A accompanying persons are welcome at= the same rate=2E PAYMENT=3A Early registration fees must be paid by bank transfer before December 31= =2C 2008 to the conference account at Open Bank (Plaza Manuel Gomez More= no 2=2C 28020 Madrid=2C Spain)=3A IBAN=3A ES1300730100510403506598 - Swi= ft code=3A OPENESMMXXX (account holder=3A LATA 2009 =96 Carlos Martin-Vi= de)=2E (Non-early) registration fees can be paid either by bank transfer to the= same account or in cash on site=2E Besides paying the registration fees=2C it is required to fill in the re= gistration form at the website of the conference=2E A receipt for the pa= yment will be provided on site=2E FUNDING=3A Up to 20 grants covering partial-board accommodation will be available f= or nonlocal PhD students=2E To apply=2C candidates must e-mail their CV = together with a copy of the document proving their present status as a P= hD student=2E IMPORTANT DATES=3A Paper submission=3A October 22=2C 2008 Notification of paper acceptance or rejection=3A December 10=2C 2008 Application for funding (PhD students)=3A December 15=2C 2008 Notification of funding acceptance or rejection=3A December 19=2C 2008 Final version of the paper for the proceedings=3A December 24=2C 2008 Early registration=3A December 31=2C 2008 Starting of the conference=3A April 2=2C 2009 Submission to the journal special issue=3A June 22=2C 2009 FURTHER INFORMATION=3A carlos=2Emartin=40urv=2Ecat ADDRESS=3A LATA 2009 Research Group on Mathematical Linguistics Rovira i Virgili University Plaza Imperial Tarraco=2C 1 43005 Tarragona=2C Spain Phone=3A +34-977-559543 Fax=3A +34-977-559597 From rrosebru@mta.ca Fri Jul 25 12:39:19 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Fri, 25 Jul 2008 12:39:19 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KMPKs-00024w-KS for categories-list@mta.ca; Fri, 25 Jul 2008 12:36:02 -0300 Content-Transfer-Encoding: 7bit From: Marco Grandis Subject: categories: Weak cubical categories Date: Fri, 25 Jul 2008 16:46:21 +0200 To: categories@mta.ca Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 24 The following preprint, exposed in my talk at CT2008, Calais, can be downloaded from my web page "The role of symmetries in cubical sets and cubical categories (On cubical categories, I)" (34 pages) http://www.dima.unige.it/~grandis/CCat.ps http://www.dima.unige.it/~grandis/CCat.pdf With best wishes Marco Grandis ______________ Abstract. Symmetric weak cubical categories were introduced in previous papers, as a basis for the study of cubical cospans in Algebraic Topology and higher cobordism. Such cubical structures are equipped with an action of the n-dimensional symmetric group on the n- dimensional component, which has been used to simplify the coherence conditions of the weak case. We give now a deeper study of the role of symmetries. The category of ordinary cubical sets has a Kan tensor product, which is non symmetric and biclosed, with left and right internal homs based on the right and left path functors. On the other hand, symmetric cubical sets have one path functor leading to one internal hom and a symmetric monoidal closed structure. Similar facts hold for cubical and symmetric cubical categories, and should play a relevant role in the sequel, the study of limits and adjunctions in these higher dimensional categories. Weak double categories, studied in four papers with R. Pare, are a cubical truncation of the present structures. While constructing examples of cubical categories, we also investigate a 'rewriting' procedure of reduction to canonical forms, which allows one to quotient a weak symmetric cubical category of cubical spans (resp. cospans), and obtain a strict symmetric cubical category of 'cubical relations' (resp. 'cubical profunctors'). ______________ From rrosebru@mta.ca Tue Aug 5 22:02:53 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Tue, 05 Aug 2008 22:02:53 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KQXQI-0001BW-Qo for categories-list@mta.ca; Tue, 05 Aug 2008 22:02:42 -0300 Date: Tue, 29 Jul 2008 21:19:54 -0700 From: PETER EASTHOPE Subject: categories: Two Category To: categories@mta.ca MIME-version: 1.0 Content-type: text/plain; charset=us-ascii Content-language: en Content-transfer-encoding: 7bit Content-disposition: inline Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 25 Folk, Subsequent to my first attempt at illustrating the Two Category, Fred Linton added, "Is it worth noting, in this jpeg, that the arithmetical max(1-A, B) for B^A coincides here with the Boolean {not}A or B for the classical B => A?" Another insight for me. Thanks. I've made a fresh sketch including a table of notations. http://carnot.yi.org/TwoCategory.jpg Apologies for the very poor graphical quality. I am working on an SVG version. Further criticisms and suggestions are welcome of course. Thanks, ... Peter E. -- http://members.shaw.ca/peasthope/ http://carnot.yi.org/ = http://carnot.pathology.ubc.ca/ From rrosebru@mta.ca Tue Aug 5 22:02:54 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Tue, 05 Aug 2008 22:02:54 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KQXOI-00012Q-3U for categories-list@mta.ca; Tue, 05 Aug 2008 22:00:38 -0300 Date: Sun, 27 Jul 2008 00:12:06 +0100 From: Reiko Heckel To: categories@mta.ca Subject: categories: Call for participation: ICGT 2008 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 26 4th International Conference on Graph Transformation Leicester (United Kingdom), September 7 - 13, 2008 http://www.cs.le.ac.uk/events/icgt2008/ The 4th Intl. Conference on Graph Transformation (ICGT 2008) will be held in Leicester (United Kingdom) in the second week of September 2008, along with a free Tutorial Introduction to Graph Transformation, a Doctoral Symposium, and workshops on * Natural Computing and Graph Transformation * Graph Computation Models * Petri Nets and Graph Transformation * Graph Transformation Tool Contest Information on the Program (including abstracts), Registration and Accommodation on-site is available at http://www.cs.le.ac.uk/events/icgt2008. Reduced rates are available for students and members of EATCS, EASST, and IFIP WG 1.3. UK PhD students funded by the EPSRC can take advantage of extra subsidies. Please note the Early Registration Deadline of 24 August. -- Prof Dr Reiko Heckel Chair of Software Engineering Department of Computer Science University of Leicester Leicester LE1 7RH United Kingdom Tel +44 (0)116 252 3406 Fax +44 (0)116 252 3915 http://www.cs.le.ac.uk/people/rh122 From rrosebru@mta.ca Tue Aug 5 22:02:54 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Tue, 05 Aug 2008 22:02:54 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KQXPK-00015h-Ob for categories-list@mta.ca; Tue, 05 Aug 2008 22:01:42 -0300 To: Categories Subject: categories: Job at Macquarie From: Ross Street Date: Tue, 29 Jul 2008 17:24:28 +1000 Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 27 Please note the job advertised on the Macquarie University Human =20 Relations page: = Note that the Desirable Criteria include applied or analysis =20 specialties. We hope there will be a more senior position advertised =20 in a year or two aimed more at category theorists. =3D=3DRoss =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D Ref. 21439 Lecturer in Mathematics - Start New Application The Department of Mathematics is seeking to appoint a Lecturer in =20 Mathematics who will contribute significantly to its research and =20 teaching activities. The successful applicant will carry out =20 independent research in an area closely related to the Department=92s =20= current research strengths in applied mathematics, analysis, category =20= theory and number theory. Areas of applied mathematics and/or =20 analysis are strongly preferred. The appointee will teach a wide =20 range of mathematics courses and supervise research projects in the =20 Department=92s undergraduate and postgraduate programs. The Department =20= seeks applicants with proven research skills, a commitment to =20 teaching and developing courses of the highest standard and a =20 willingness to work with colleagues on new initiatives in the Faculty =20= and University. Essential Selection Criteria: PhD (or submitted); established =20 research record or evidence of outstanding research potential in =20 applied mathematics, analysis, category theory or number theory =20 (provided by one or two significant publications, evidence of =20 contributions to key research outcomes either individually or as a =20 member of a group, together with an outline of a coherent plan for =20 future research); interest in developing research links within, and =20 outside, the University (particular plans to develop cross-=20 disciplinary links within the University, research links with =20 external institutions or industry research collaborations should be =20 indicated); interest and ability to teach undergraduate mathematics =20 across the full range of service and specialised courses (as =20 demonstrated by documented experience in tutoring, lecturing or =20 workshop presentation); well-developed interpersonal, written =20 communication skills. Desirable Selection Criteria: Research background in applied =20 mathematics or analysis particularly in one of the following areas: =20 (i) analytical-numeral techniques in wave diffraction and/or interest =20= in applications to acoustic or electromagnetic waves, (ii) =20 applications of non-linear dynamical systems especially in electronic =20= and physical systems, (iii) harmonic analysis and partial =20 differential equations involving the theory of singular integrals or =20 related topics; experience in industry-collaborative research or =20 experience of active participation in an extensive national/=20 international research collaboration; established international =20 recognition (as demonstrated by publications, research grants, =20 citations or invited conference presentations); substantial =20 university-level teaching experience in mathematics across the full =20 range of service and specialised courses. Enquiries: Applicants are strongly encouraged to contact Professor =20 Paul Smith on +61-2-9850-8944 or e-mail pdsmith@maths.mq.edu.au Package: Lecturer (Level B) from $81,682 pa including base salary =20 $69,022 pa to $81,847 pa, annual leave loading and 17% employer=92s =20 superannuation. The position is available on a full-time (continuing) basis. =20 Probationary conditions may apply. Selection criteria must be =20 addressed in the application. The appointment is currently governed =20 by the terms of the Macquarie University Enterprise Agreement 2006-2009. Please visit www.jobs.mq.edu.au to apply online. Please note that =20 only those applications submitted via the Macquarie University Online =20= Recruitment System will be accepted. Closing Date: 30 August 2008 Macquarie University is an Equal Opportunity Employer with a =20 commitment to diversity and social inclusion. We encourage =20 applications from Indigenous Australians; people with a disability; =20 those from culturally and linguistically diverse backgrounds; and =20 women (particularly for senior and non-traditional vacancies). Please note that only those applications submitted via the Macquarie =20 University Online Recruitment System will be accepted. =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D Emeritus Professor Ross Street FAA Mathematics Department, Macquarie University, NSW 2109, Australia Web: www.math.mq.edu.au/~street/ Email: street@math.mq.edu.au From rrosebru@mta.ca Tue Aug 5 22:02:54 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Tue, 05 Aug 2008 22:02:54 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KQXNm-00011N-81 for categories-list@mta.ca; Tue, 05 Aug 2008 22:00:06 -0300 Date: Fri, 25 Jul 2008 20:08:18 +0200 From: Patrick Blackburn Subject: categories: Review of Symbolic Logic (RSL) Content-type: text/plain To: undisclosed-recipients:; Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: RO X-Status: X-Keywords: X-UID: 28 The Association of Symbolic Logic (ASL) has just launched a new journal, the Review of Symbolic Logic (RSL). It is published by Cambridge University Press. The first issue has just appeared and you can see the table of contents and download articles from the journal's CUP homepage at: http://journals.cambridge.org/action/displayIssue?jid=RSL&volumeId=1&issueId=01# RSL is devoted to philosophical and non-classical logics and their applications, history and philosophy of logic, and philosophy and methodology of mathematics. Submissions are welcome. From rrosebru@mta.ca Tue Aug 5 22:03:18 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Tue, 05 Aug 2008 22:03:18 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KQXQk-0001E7-Mq for categories-list@mta.ca; Tue, 05 Aug 2008 22:03:10 -0300 From: Pedro Resende To: Categories list Content-Type: text/plain; charset=WINDOWS-1252; format=flowed; delsp=yes Content-Transfer-Encoding: quoted-printable Subject: categories: two preprints Mime-Version: 1.0 (Apple Message framework v928.1) Date: Wed, 30 Jul 2008 16:15:43 +0100 Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 29 I have placed in the arXiv the following two preprints that correspond =20= to a part of my CT08 talk: =95 Groupoid actions as quantale modules, 14 pp.; = http://arxiv.org/abs/arXiv:0807.3859=20 . =95 Groupoid sheaves as Hilbert modules, 27 pp.; = http://arxiv.org/abs/arXiv:0807.4848=20 . Best, Pedro= From rrosebru@mta.ca Tue Aug 5 22:04:18 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Tue, 05 Aug 2008 22:04:18 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KQXRi-0001JQ-F7 for categories-list@mta.ca; Tue, 05 Aug 2008 22:04:10 -0300 Date: Wed, 30 Jul 2008 11:19:24 -0400 (EDT) From: Michael Barr To: Categories list Subject: categories: Searching for Grothendieck MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 30 I would like to call the attention of the categorical community to the very interesting post http://www.fermentmagazine.org/Quest88.html It reports the successful quest in 1988 of Roy Lisker to meet Grothendieck. I first met Roy nearly 55 years ago when we were in a HS math club. I lost track of him for several decades and then met him again in Peter Freyd's office at Penn, probably in 1990. Since then I have had desultory e-contact with him (plus running into him once in person). I read this then, but he has now posted it online. Eventually, I will put a copy on my own ftp site. Michael From rrosebru@mta.ca Tue Aug 5 22:05:24 2008 -0300 Return-path: Envelope-to: categories-list@mta.ca Delivery-date: Tue, 05 Aug 2008 22:05:24 -0300 Received: from Majordom by mailserv.mta.ca with local (Exim 4.61) (envelope-from ) id 1KQXSl-0001OP-TM for categories-list@mta.ca; Tue, 05 Aug 2008 22:05:15 -0300 Subject: categories: Paper on slice stability in Locale Theory Date: Thu, 31 Jul 2008 09:09:12 +0100 From: "Townsend, Christopher" To: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Sender: cat-dist@mta.ca Precedence: bulk Message-Id: Status: O X-Status: X-Keywords: X-UID: 31 I was sorry not to be at the Calais meeting the other week and had hoped to have the paper=20 =20 Aspects of slice stability in Locale Theory =20 http://www.christophertownsend.org/Documents/SliceStability_v30.pdf =20 ready for it.=20 =20 This paper proves that a particular axiomatic approach to locale theory is slice stable and then uses this slice stability to prove some known locale theory/topos theory results. All the results are known (aside from a conjecture on localic subgroupoids) so it is really an investigation into this particular axiomatisation rather than a presentation of new results.=20 It gives what I think is a novel proof of the well known slice stability result: Loc/Y =3D Loc_Sh(Y).=20 =20 Feedback is welcome. For example, I have always attributed the result Loc/Y =3D Loc_Sh(Y) to Joyal and Tierney. Am I right?=20 =20 Regards, Christopher=20 =20