From rzach at ucalgary.ca Thu Apr 10 22:01:38 2008 From: rzach at ucalgary.ca (Richard Zach) Date: Thu Apr 10 22:01:44 2008 Subject: [Alta-Logic] Talk: John Kearns: Illocutionary Logic (Friday April 18, 4 pm) Message-ID: <1207886499.7002.6.camel@mx80> Logic Talk! John Kearns Department of Philosophy SUNY Buffalo ?Illocutionary Logic: Truth and Commitment. An Enlarged Conception of Semantics, and an Application to the Sorites Paradox Friday, April 18 (BSD!) 4:00 pm 1253 Social Sciences A basic presentation of systems of illocutionary logic. These systems have two semantic levels, one concerned with truth conditions of statements, the second with commitment conditions of illocutionary acts. (Performing some acts will commit a person to perform others.) These systems motivate shifting the boundary between semantics and pragmatics. The systems also provide the conceptual resources for understanding issues concerning vagueness. From rzach at ucalgary.ca Fri Sep 19 09:55:39 2008 From: rzach at ucalgary.ca (Richard Zach) Date: Fri Sep 19 10:46:39 2008 Subject: [Alta-Logic] Logic and Category Theory Group Rebooted! Message-ID: <1221839739.14214.109.camel@mx80> Hi, Over the past year, the Calgary Peripatetic Research Group in Logic and Category Theory has been on hiatus, more or less. But now it's starting up again! We'll try to have weekly meetings again, in the Fall term they'll be on Wednesdays, 12:30 to 2:00 or so. I'll start it off with a history of logic talk titled "The decision problem and the history of metalogic" next Wednesday, September 24. This is an exciting year for logic and category theory at Calgary. Krister Segerberg is Killam Visiting Scholar and Visiting Professor in the Philosophy Department. Brian Redmond is a new postdoc working with Robin Cockett. There's a bunch of new students interested in logic in all departments involved. Come to the first meeting and get to know everyone! We have a fancy new website! It lives at http://www.ucalgary.ca/cprglct/ You'll find a calendar of events, an RSS feed for logic & category theory-related news items, a list of people at the UofC interested in logic & category theory, etc. Plus the abstract of my talk. In order for the website to be as useful as possible, please: - Let me know what you want me to put down for your entry on the "People" page (if you think you should be on there) - Send me brief descriptions of your research projects (if they're related) for the "Research" page - Post news items and events of interest on the website *yourself*. Instructions are on the "For Group Members" page: http://www.ucalgary.ca/cprglct/members And then, of course: - Come to our talks - Tell Gillman Payette when and about what *you* want to give a talk. His email is ggpayett@ucalgary.ca . - Let other people know who are interested but who may not be on our email list. Undergrads too! - Subscribe to the email list or add the RSS feed to your feed readers. (I'm sending this first announcement out more widely than usual, but future announcements will only go to the alta-logic-l list.) Links here: http://www.ucalgary.ca/cprglct/contact See you Wednesday, I hope! Best, Richard -- Richard Zach ...... http://www.ucalgary.ca/~rzach/ Associate Professor, Department of Philosophy University of Calgary, Calgary, AB T2N 1N4, Canada From rzach at ucalgary.ca Wed Sep 24 00:21:18 2008 From: rzach at ucalgary.ca (Richard Zach) Date: Wed Sep 24 01:17:00 2008 Subject: [Alta-Logic] Reminder: Talk today (Logic and Category Theory Group Rebooted!) In-Reply-To: <1221839739.14214.109.camel@mx80> References: <1221839739.14214.109.camel@mx80> Message-ID: <1222237278.27676.55.camel@mx80> Today, 12:30 ICT 616: first meeting and a talk on The Decision Problem and the History of Metalogic (Richard Zach) http://www.ucalgary.ca/cprglct/node/16 And a reminder to send me information for the "people" page on the website. Best, R On Fri, 2008-09-19 at 09:55 -0600, Richard Zach wrote: > Hi, > > Over the past year, the Calgary Peripatetic Research Group in Logic and > Category Theory has been on hiatus, more or less. But now it's starting > up again! We'll try to have weekly meetings again, in the Fall term > they'll be on Wednesdays, 12:30 to 2:00 or so. I'll start it off with a > history of logic talk titled "The decision problem and the history of > metalogic" next Wednesday, September 24. > > This is an exciting year for logic and category theory at Calgary. > Krister Segerberg is Killam Visiting Scholar and Visiting Professor in > the Philosophy Department. Brian Redmond is a new postdoc working with > Robin Cockett. There's a bunch of new students interested in logic in > all departments involved. Come to the first meeting and get to know > everyone! > > We have a fancy new website! It lives at > http://www.ucalgary.ca/cprglct/ > > You'll find a calendar of events, an RSS feed for logic & category > theory-related news items, a list of people at the UofC interested in > logic & category theory, etc. Plus the abstract of my talk. > > In order for the website to be as useful as possible, please: > > - Let me know what you want me to put down for your entry on the > "People" page (if you think you should be on there) > - Send me brief descriptions of your research projects (if they're > related) for the "Research" page > - Post news items and events of interest on the website *yourself*. > Instructions are on the "For Group Members" page: > http://www.ucalgary.ca/cprglct/members > > And then, of course: > > - Come to our talks > - Tell Gillman Payette when and about what *you* want to give a talk. > His email is ggpayett@ucalgary.ca . > - Let other people know who are interested but who may not be on our > email list. Undergrads too! > - Subscribe to the email list or add the RSS feed to your feed readers. > (I'm sending this first announcement out more widely than usual, but > future announcements will only go to the alta-logic-l list.) Links here: > http://www.ucalgary.ca/cprglct/contact > > See you Wednesday, I hope! > > Best, > Richard From ggpayett at ucalgary.ca Sat Sep 27 10:05:26 2008 From: ggpayett at ucalgary.ca (ggpayett@ucalgary.ca) Date: Sat Sep 27 10:05:30 2008 Subject: [Alta-Logic] Logic and Category Theory Group: Talk on Oct. 1st Message-ID: <1683.66.222.240.216.1222531526.squirrel@66.222.240.216> Title: Worlds and Times Date: October 1, 2008 (Wednesday) Room: ICT 616 Time: 1pm--2pm Speaker: Gillman Payette (Philosophy) Abstract: The Diodorian account of alethic modality runs something like this: P is possible, if P is now true, or will be true. We can add to this definition that P has been true since if it has been the case that P, then P had better be possible. But this collapses what is possible to what merely has, is or will be. That seems deterministic, and it seems to miss the idea that there are things that are possible, but not actual. Current modal logic which is done with possible world semantics does match our intuitions, but it simply says that there is a relation R on the set of possible worlds which gives us the alternative, accessible or relatively possible, possible worlds to the actual. But what is this relation R? The question is not whether this relation is transitive, symmetric, etc., but what it is. There is something that the Diodorian account gets right: the before/after relation is something that we can make sense of. But if we use worlds and times, we can give an account of the semantics of various uses of 'possible' that defines R in terms of before/after and matches our intuitions. In this talk I will explain how to do this, and explain possible world semantics. This is joint work done with Peter Schotch at Dalhousie University. From ggpayett at ucalgary.ca Fri Oct 3 15:32:52 2008 From: ggpayett at ucalgary.ca (ggpayett@ucalgary.ca) Date: Fri Oct 3 15:32:57 2008 Subject: [Alta-Logic] Logic and Category Theory Group Message-ID: <1307.136.159.45.106.1223069572.squirrel@136.159.45.106> Title: Fundamentals of Fra?ss? theory: the art of gluing structures together. Start: 10/08/2008 - 13:00 End: 10/08/2008 - 14:00 Room: ICT 616 Given a class K of finite structures in a given language, is it possible to find a structure X in the same language so that K is exactly the class of finite substructures of X? If so, what are the generic properties of such an X? The purpose of this talk is to present an old theory that answers the first question, as well as recent developments that answer the second one. -- Gillman Payette Department of Philosophy University of Calgary 2500 University Drive NW Calgary, AB T2N 1N4, Canada Ph 403.220.7518 Fax 403.289.5698 From ggpayett at ucalgary.ca Fri Oct 3 15:53:47 2008 From: ggpayett at ucalgary.ca (ggpayett@ucalgary.ca) Date: Mon Oct 6 11:18:03 2008 Subject: [Alta-Logic] Logic and Category Theory Group (New and Improved with the speaker's name!) Message-ID: <1515.136.159.45.106.1223070827.squirrel@136.159.45.106> Speaker: Lionel Nguyen Van Th? Title: Fundamentals of Fra?ss? theory: the art of gluing structures together. Start: 10/08/2008 - 13:00 End: 10/08/2008 - 14:00 Room: ICT 616 Given a class K of finite structures in a given language, is it possible to find a structure X in the same language so that K is exactly the class of finite substructures of X? If so, what are the generic properties of such an X? The purpose of this talk is to present an old theory that answers the first question, as well as recent developments that answer the second one. -- Gillman Payette Department of Philosophy University of Calgary 2500 University Drive NW Calgary, AB T2N 1N4, Canada Ph 403.220.7518 Fax 403.289.5698 -- Gillman Payette Department of Philosophy University of Calgary 2500 University Drive NW Calgary, AB T2N 1N4, Canada Ph 403.220.7518 Fax 403.289.5698 From ggpayett at ucalgary.ca Wed Oct 8 11:09:18 2008 From: ggpayett at ucalgary.ca (ggpayett@ucalgary.ca) Date: Wed Oct 8 11:09:23 2008 Subject: [Alta-Logic] Category theory and logic talk: Reminder and Next Week Message-ID: <1211.136.159.45.5.1223485758.squirrel@136.159.45.5> Reminder about todays talk at 14:00 by Lionel Nguyen Van Th?, in ICT 616 on Fraisse theory. Title: Modal Logic: How it Began Start: 10/15/2008 - 13:00 End: 10/15/2008 - 14:00 Room: ICT 616 Speaker: Krister Segerberg Abstract: Modal logic was invented by a philosopher and then developped by philosophers and mathematicians. Today it has, to a considerable extent, been taken over by computer scientists. I will try to say something about all this. R -- Gillman Payette Department of Philosophy University of Calgary 2500 University Drive NW Calgary, AB T2N 1N4, Canada Ph 403.220.7518 Fax 403.289.5698 From ggpayett at ucalgary.ca Wed Oct 8 11:11:08 2008 From: ggpayett at ucalgary.ca (ggpayett@ucalgary.ca) Date: Wed Oct 8 11:11:18 2008 Subject: [Alta-Logic] Category theory and logic talk: (revised) Reminder and Next Week Message-ID: <1236.136.159.45.5.1223485868.squirrel@136.159.45.5> Reminder about todays talk at 13:00 by Lionel Nguyen Van Th?, in ICT 616 on Fraisse theory. Title: Modal Logic: How it Began Start: 10/15/2008 - 13:00 End: 10/15/2008 - 14:00 Room: ICT 616 Speaker: Krister Segerberg Abstract: Modal logic was invented by a philosopher and then developped by philosophers and mathematicians. Today it has, to a considerable extent, been taken over by computer scientists. I will try to say something about all this. R -- Gillman Payette Department of Philosophy University of Calgary 2500 University Drive NW Calgary, AB T2N 1N4, Canada Ph 403.220.7518 Fax 403.289.5698 -- Gillman Payette Department of Philosophy University of Calgary 2500 University Drive NW Calgary, AB T2N 1N4, Canada Ph 403.220.7518 Fax 403.289.5698 From rzach at ucalgary.ca Wed Oct 8 17:00:44 2008 From: rzach at ucalgary.ca (Richard Zach) Date: Wed Oct 8 17:00:45 2008 Subject: [Alta-Logic] Ulrich Kohlenbach to speak Dec 5? Message-ID: <1223506844.3200.9.camel@mx80> Hi, Ulrich Kohlenbach is going to attend a workshop at BIRS the second week of December, and I've explored the possibility of him coming to Calgary before going to Banff to give us a talk on Friday, December 5. Before we finalize plans, I'd like to get an idea how much interest there is--and how much commitment to attend a talk on the last day of class! Kohlenbach has done some very exciting work in "proof mining" applying proof theoretic methods to proofs of "actual" mathematical theorems to extract information such as bounds for forall - exists theorems in analysis. He has just written a book on this: http://www.springer.com/math/book/978-3-540-77532-4 Ulrich Kohlenbach presents an applied form of proof theory that has led in recent years to new results in number theory, approximation theory, nonlinear analysis, geodesic geometry and ergodic theory (among others). This applied approach is based on logical transformations (so-called proof interpretations) and concerns the extraction of effective data (such as bounds) from prima facie ineffective proofs as well as new qualitative results such as independence of solutions from certain parameters, generalizations of proofs by elimination of premises. The book first develops the necessary logical machinery emphasizing novel forms of G?del's famous functional ('Dialectica') interpretation. It then establishes general logical metatheorems that connect these techniques with concrete mathematics. Finally, two extended case studies (one in approximation theory and one in fixed point theory) show in detail how this machinery can be applied to concrete proofs in different areas of mathematics. Here's the second chapter that explains the approach: http://www.springer.com/cda/content/document/cda_downloaddocument/9783540775324-c2.pdf?SGWID=0-0-45-557108-p173805804 The entire book is online here: http://www.springerlink.com/content/978-3-540-77532-4 His website is here: http://www.mathematik.tu-darmstadt.de/~kohlenbach/ Richard From rzach at ucalgary.ca Wed Oct 15 09:03:17 2008 From: rzach at ucalgary.ca (Richard Zach) Date: Wed Oct 15 09:03:09 2008 Subject: [Alta-Logic] Talk today: Segerberg, Modal Logic: How it Began (1pm, 616 ICT) Message-ID: <1224082997.5253.12.camel@mx80> Modal Logic: How it Began (Segerberg) Start: 10/15/2008 - 13:00 End: 10/15/2008 - 14:00 Speaker: Krister Segerberg Room: ICT 616 Modal logic was invented by a philosopher and then developped by philosophers and mathematicians. Today it has, to a considerable extent, been taken over by computer scientists. I will try to say something about all this. From ggpayett at ucalgary.ca Mon Oct 20 09:08:30 2008 From: ggpayett at ucalgary.ca (ggpayett@ucalgary.ca) Date: Mon Oct 20 09:08:38 2008 Subject: [Alta-Logic] Talk On Wednesday Message-ID: <4685.66.222.240.216.1224515310.squirrel@66.222.240.216> Speaker: David Boutillier Room: ICT 616 Time: 13:00 Frege?s logicist programme is celebrated as the first account of arithmetical knowledge that is based on a formulation and defence of the thesis that fundamental arithmetical laws can be obtained on the basis of definitions and logic alone. It is well-known that Frege?s attempt to carry out this programme, by deriving the principles of (second-order) Peano arithmetic from the basic laws of a system of second-order logic, runs aground due to its reliance on what is known as Basic Law V, which Russell showed to entail a contradiction. Various attempts, both historical and contemporary, have been made to show that Russell?s paradox can be avoided. But even if one of these attempts succeeds, a number of questions remain concerning the underlying logic on which the logicist thesis depends. One of these questions concerns the assumption that logic is somehow epistemologically privileged. The question is whether the philosophy of logic can provide a clear and satisfactory explanation of the fundamentality of logic. My paper describes a strategy for providing such an explanation, and offers a sketch of one way in which the strategy might be carried out. The strategy rests on two claims: that logical laws are ?analytic of? primitive logical concepts, and that primitive logical concepts are given to us as the invariants of the transformations of a given domain of individuals, which respects the structure of the properties of the individuals in that domain. The sketch of how the strategy might be carried out involves a discussion of Tarski?s extension of Klein?s ?Erlanger Programm,? which yields an explication of the general concept of logical notion, and a modification of Tarski?s explication, which places it within a functional type framework fashioned after the simple theory of types. -- Gillman Payette Department of Philosophy University of Calgary 2500 University Drive NW Calgary, AB T2N 1N4, Canada Ph 403.220.7518 Fax 403.289.5698 From ggpayett at ucalgary.ca Tue Oct 28 10:49:35 2008 From: ggpayett at ucalgary.ca (ggpayett@ucalgary.ca) Date: Tue Oct 28 10:49:43 2008 Subject: [Alta-Logic] Introduction to Turing Categories 1 Message-ID: <1700.136.159.161.168.1225212575.squirrel@136.159.161.168> Speaker: Robin Cockett Date: Wednesday Oct 29th Time: 13:00 Room: ICT 616 Abstract: This is joint work with Pieter Hofstra and is part of a program to provide a more abstract basis for computability theory. The work (among other aspects) unifies two strands: one pioneered by Di Poala and Heller and the other by Moggi and Longo. The former initiated the study of computability from a categorical perspective, however, fundamentally assumed that computability required the presence of partiality (functions which are not totally defined). The latter considered total categories of computable functions given by combinatory algebras and excluded the possibility that there could be partiality! Turing categories unify these viewpoints but also open up other possibilities which are unexpected. The first talk will lay out the basic theory and work toward some of the basic results of computability. -- Gillman Payette Department of Philosophy University of Calgary 2500 University Drive NW Calgary, AB T2N 1N4, Canada Ph 403.220.7518 Fax 403.289.5698 From ggpayett at ucalgary.ca Tue Nov 4 22:00:06 2008 From: ggpayett at ucalgary.ca (ggpayett@ucalgary.ca) Date: Tue Nov 4 22:00:11 2008 Subject: [Alta-Logic] Turing Categories II Message-ID: <2175.137.186.49.92.1225861206.squirrel@137.186.49.92> Start: 11/05/2008 - 13:00 End: 11/05/2008 - 14:00 Speaker: Robin Cockett Room: ICT 616 Abstract: More on Turing categories. -- Gillman Payette Department of Philosophy University of Calgary 2500 University Drive NW Calgary, AB T2N 1N4, Canada Ph 403.220.7518 Fax 403.289.5698 From ggpayett at ucalgary.ca Tue Nov 11 20:54:19 2008 From: ggpayett at ucalgary.ca (ggpayett@ucalgary.ca) Date: Tue Nov 11 20:54:24 2008 Subject: [Alta-Logic] Turing Categories III Message-ID: <4293.137.186.49.92.1226462059.squirrel@137.186.49.92> Speaker: Robin Cockett Room ICT 616 Time: 13:00-14:00 Abstract: The Third tutorial on Turing Categories. -- Gillman Payette Department of Philosophy University of Calgary 2500 University Drive NW Calgary, AB T2N 1N4, Canada Ph 403.220.7518 Fax 403.289.5698 From ggpayett at ucalgary.ca Mon Nov 17 10:11:43 2008 From: ggpayett at ucalgary.ca (ggpayett@ucalgary.ca) Date: Mon Nov 17 10:11:58 2008 Subject: [Alta-Logic] Modal logics of Change Message-ID: <3903.137.186.49.92.1226941903.squirrel@137.186.49.92> Start: 11/19/2008 - 13:00 End: 11/19/2008 - 14:00 Speaker: Krister Segerberg Room: ICT 616 Abstract: The logics I have in mind are David Lewis?s logic of conditionals, Pratt?s dynamic logic, and the logic of belief change due to Alchourr?n, G?rdenfors and Makinson. I will try to say something about them and how they are related. -- Gillman Payette Department of Philosophy University of Calgary 2500 University Drive NW Calgary, AB T2N 1N4, Canada Ph 403.220.7518 Fax 403.289.5698 From ggpayett at ucalgary.ca Thu Nov 20 16:56:03 2008 From: ggpayett at ucalgary.ca (ggpayett@ucalgary.ca) Date: Thu Nov 20 16:56:02 2008 Subject: [Alta-Logic] Talk on Friday Dec. 5: Ulrich Kohlenbach Message-ID: <1450.137.186.49.92.1227225363.squirrel@137.186.49.92> Ulrich Kohlenbach Mathematics, TU Darmstadt http://www.mathematik.tu-darmstadt.de/~kohlenbach/ Proof Interpretations, "Hard Analysis" and Ergodic Theory MS 452 for Friday, Dec. 5 at 2pm Abstract: Building upon pioneering ideas of G. Kreisel, going back to the 50's, a new applied form of proof theory emerged during the last 20 year. Here the emphasis is on applications of so-called proof interpretations to concrete mathematical proofs with the aim of extracting effective bounds as well as new uniformity results from prima facie ineffective proofs. This has led to new results in number theory, approximation theory, nonlinear analysis, geodesic geometry and ergodic theory as well as the development of logical metatheorems that explain these results as instances of general logical phenomena. Specialized to the examples discussed in T. Tao's recent essay "Soft analysis, hard analysis, and the finite convergence principle" the logical machinery yields very much the type of quantitative finitary versions of analytical theorems as considered by Tao. We will argue that such logical methods based on appropriate functional interpretations provide a systematic approach to Tao's program of "hard analysis". We will also give a recent application (joint work with L. Leustean) of proof mining to ergodic theory. -- Gillman Payette Department of Philosophy University of Calgary 2500 University Drive NW Calgary, AB T2N 1N4, Canada Ph 403.220.7518 Fax 403.289.5698 From ggpayett at ucalgary.ca Thu Nov 20 17:07:26 2008 From: ggpayett at ucalgary.ca (ggpayett@ucalgary.ca) Date: Thu Nov 20 17:07:29 2008 Subject: [Alta-Logic] Talk on wednesday 26th Nov. Message-ID: <1469.137.186.49.92.1227226046.squirrel@137.186.49.92> Start: 11/26/2008 - 13:00 End: 11/26/2008 - 14:00 Room: ICT 616 Speaker: Gillman Payette Abstract: Category theory presents itself as useful in understanding and characterizing phenomena in logic. One notion that is common in category theory is that of adjoint functor. I will focus on the uses of adjoint functors in two areas of logic: Translation and identification of logics. I will describe some necessary and sufficient conditions for the existence of adjunctions of particular interest to the logician. I will use these to present some of the most viable ways of construing, in general, translations between logics, and identity between logics. -- Gillman Payette Department of Philosophy University of Calgary 2500 University Drive NW Calgary, AB T2N 1N4, Canada Ph 403.220.7518 Fax 403.289.5698 From ggpayett at ucalgary.ca Wed Nov 26 11:17:54 2008 From: ggpayett at ucalgary.ca (ggpayett@ucalgary.ca) Date: Wed Nov 26 11:18:01 2008 Subject: [Alta-Logic] Reminder: Talk on wednesday 26th Nov. Message-ID: <2586.136.159.141.126.1227723474.squirrel@136.159.141.126> Just a reminder. Start: 11/26/2008 - 13:00 End: 11/26/2008 - 14:00 Room: ICT 616 Speaker: Gillman Payette Abstract: Category theory presents itself as useful in understanding and characterizing phenomena in logic. One notion that is common in category theory is that of adjoint functor. I will focus on the uses of adjoint functors in two areas of logic: Translation and identification of logics. I will describe some necessary and sufficient conditions for the existence of adjunctions of particular interest to the logician. I will use these to present some of the most viable ways of construing, in general, translations between logics, and identity between logics. -- Gillman Payette Department of Philosophy University of Calgary 2500 University Drive NW Calgary, AB T2N 1N4, Canada Ph 403.220.7518 Fax 403.289.5698 -- Gillman Payette Department of Philosophy University of Calgary 2500 University Drive NW Calgary, AB T2N 1N4, Canada Ph 403.220.7518 Fax 403.289.5698 From rzach at ucalgary.ca Fri Dec 5 23:54:34 2008 From: rzach at ucalgary.ca (Richard Zach) Date: Fri Dec 5 23:54:41 2008 Subject: [Alta-Logic] Talk Dec 9: Katalin =?iso-8859-1?q?Bimb=F3=2C?= Symmetric Gaggles Message-ID: <1228546474.6365.2.camel@mx80> NOTE ROOM! Tuesday, December 9, 2008, 1 pm 1253 Social Sciences Symmetric gaggles Katalin Bimb? (University of Alberta, Philosophy) Lambek calculus has been extended in various ways. Grishin duplicated Lambek calculus based on algebraic considerations; this leads to questions of interactions between the operations. Dunn and Hardegree proved that for an algebraic cut rule to hold, certain (weak) distribution has to obtain between (intensional) conjunction and disjunction. Recently, Kurtonina and Moortgat argued for similar principles based on linguistic examples. This talk is about symmetric gaggles that are ggl's (generalized Galois logics) in which there is some distributivity between operations from the fusion (o) and fission (+) families. I will present representation (including isomorphic representation) theorems based on topological relational frames. The topological frames are algebraically realizable that yields duality theorems. Interestingly, the various distributivity principles turn out to be canonical independently of each other. The talk is based on a joint paper (that is not yet published) by J. M. Dunn and me.