From ggpayett at ucalgary.ca Thu Jan 8 11:36:24 2009 From: ggpayett at ucalgary.ca (ggpayett@ucalgary.ca) Date: Thu Jan 8 11:36:40 2009 Subject: [Alta-Logic] Talk On Wednesday Jan 14 Message-ID: <3988.137.186.49.92.1231439784.squirrel@137.186.49.92> Title: On Authorisation Languages and Formalisms Start: 01/14/2009 - 13:00 End: 01/14/2009 - 14:00 Room: ICT 616 Speaker: Nicholas Sheppard Abstract: Access control systems are widely used to restrict access to sensitive files and records stored on computer systems. Numerous authorisation languages have been proposed in which the policy of an access control system can be described, some based on traditional approaches to access control, and others based on formal logics. In this talk, I will give an overview of access control systems and authorisation languages. I will pay particular attention to "rights expression languages" used in intellectual property protection, which are typically defined in natural-language specification documents and have been criticised for their ambiguity. I will give an overview of attempts to formalise rights expression language with logical bases, and propose a new approach based on a procedural interpretation of rights expressions. -- 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 Jan 21 10:05:46 2009 From: rzach at ucalgary.ca (Richard Zach) Date: Wed Jan 21 10:06:36 2009 Subject: [Alta-Logic] CfP: S.E.P 2009 (Edmonton) Message-ID: <1232557546.17978.135.camel@mx80> Hi all, Our colleagues to the north are organizing this year's Society for Exact Philosophy conference. Deadline is Jan 31. If you have something that would fit (ie, something on the intersection of logic, language, and philosophy), maybe you'd consider sending it there. -R The 37th annual meeting of the Society for Exact Philosophy will be held at the University of Alberta in Edmonton, Alberta. May 7-9, 2009. CALL FOR PAPERS The Society for Exact Philsophy invites submissions for its 2009 meeting. Paper submissions in all areas of analytic philosophy are welcomed. Invited speakers: Alasdair Urquhart (Toronto), SEP President Susan Vineberg (Wayne State), Edward Zalta (Stanford). A selection of papers from the conference will be published in a special volume of Synthese, guest edited by Marc Moffett. SUBMISSION DEADLINE: January 31st, 2009. Submission Instructions Authors are requested to submit their papers according to the following guidelines: 1) Papers should be prepared for blind refereeing, 2) put into PDF file format, and 3) sent as an email attachment to the address given below -- where 4) the subject line of the submission email should include the key-phrase "SEP submission", and 5) the body text of the email message should constitute a cover page for the submission by including i) return email address, ii) author's name, iii) affiliation, iv) paper title, and v) short abstract. Electronic submissions should be sent to Nota Bene: All submissions will receive email confirmation of receipt. If your submission does not soon result in such an email confirmation, please send an inquiry either to the above address or to the local organizer. More Information-- For more information on the conference and conference accommodations, visit the conference web site at: Information on the Society and its previous meetings is on the web at . "The SEP is dedicated to providing sustained discussion among researchers who believe that rigorous methods have a place in philosophical investigations." Join us in Edmonton! From ggpayett at ucalgary.ca Mon Jan 26 15:37:19 2009 From: ggpayett at ucalgary.ca (ggpayett@ucalgary.ca) Date: Mon Jan 26 15:37:33 2009 Subject: [Alta-Logic] Next Seminar: NOTE THE NEW TIME Message-ID: <3998.137.186.49.92.1233009439.squirrel@137.186.49.92> Title: Social commitment logics for multi agent communication Place: ICT 616 Time: Tuesday, Jan 27th, 12:00 Speaker: Rob Kremer Title: Multi-Agent System Communication Paradigms Abstract: Multi-Agent Systems seem like a good idea -- solve problems be using several different specialized agents who cooperate to reach a solution. Aside from obvious problems (such as disagreements, inconsistencies, and composition), communication is significant impediment. Agents may be written by different people in different styles, with different objectives. Simple communication protocols tend to be brittle, and fail because not all agents may behave identically, and may respond in unanticipated ways. Attempts to formalize and standardize communication, such as the one the Foundation for Intelligent Physical Agents (FIPA) developed using BDI (Belief, Desire, Intension) semantics, encountered difficulties that made implementation and conformance difficult. Some of these problems stem from the FIPA standard's requirement that all agents model the beliefs, desires, and intentions of all other agents, which makes for a rather unnaturally omniscient society of agents. One way to address this issue is to neglect the modeling of the "minds" of other agents, and model only the /social commitments/ agents undertake (or fulfill) in the course of their conversations. To achieve this, conversations are modeled as sequences of /speech acts/, where rules or /policies/ (which may be considered /social norms/) translate from the speech acts to the instantiation or deletion of social commitments among the participant agents. -- 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 Jan 26 15:58:31 2009 From: ggpayett at ucalgary.ca (ggpayett@ucalgary.ca) Date: Mon Jan 26 15:58:42 2009 Subject: [Alta-Logic] Next Seminar: Feb 3, not Jan 27. NOTE THE NEW TIME Message-ID: <4140.137.186.49.92.1233010711.squirrel@137.186.49.92> Place: ICT 616 Time: Tuesday, Feb 3rd, 12:00 Speaker: Rob Kremer Title: Multi-Agent System Communication Paradigms Abstract: Multi-Agent Systems seem like a good idea -- solve problems be using several different specialized agents who cooperate to reach a solution. Aside from obvious problems (such as disagreements, inconsistencies, and composition), communication is significant impediment. Agents may be written by different people in different styles, with different objectives. Simple communication protocols tend to be brittle, and fail because not all agents may behave identically, and may respond in unanticipated ways. Attempts to formalize and standardize communication, such as the one the Foundation for Intelligent Physical Agents (FIPA) developed using BDI (Belief, Desire, Intension) semantics, encountered difficulties that made implementation and conformance difficult. Some of these problems stem from the FIPA standard's requirement that all agents model the beliefs, desires, and intentions of all other agents, which makes for a rather unnaturally omniscient society of agents. One way to address this issue is to neglect the modeling of the "minds" of other agents, and model only the /social commitments/ agents undertake (or fulfill) in the course of their conversations. To achieve this, conversations are modeled as sequences of /speech acts/, where rules or /policies/ (which may be considered /social norms/) translate from the speech acts to the instantiation or deletion of social commitments among the participant agents. -- 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 Mon Feb 9 15:40:32 2009 From: ggpayett at ucalgary.ca (Gillman Payette) Date: Mon Feb 9 15:40:50 2009 Subject: [Alta-Logic] Talks Message-ID: <4539.136.159.141.126.1234219232.squirrel@136.159.141.126> So there will not be a talk tomorrow, however we were wondering if many people will be away newxt week? Please let me know. -- Gillman Payette Department of Philosophy University of Calgary 2500 University Drive NW Calgary, AB T2N 1N4, Canada Ph 403.220.6463 Fax 403.289.5698 From ggpayett at ucalgary.ca Mon Feb 23 12:29:09 2009 From: ggpayett at ucalgary.ca (Gillman Payette) Date: Mon Feb 23 12:29:35 2009 Subject: [Alta-Logic] Talk on Tuesday Feb 24 Message-ID: <2455.136.159.141.126.1235417349.squirrel@136.159.141.126> Speaker: Brian Redmond Room: ICT 616 Start: 02/24/2009 - 12:00 End: 02/24/2009 - 13:00 Abstract: In this talk, I will present some recent work with Robin Cockett and Mike Burrell on a type system for a functional style programming language called Pola which is complete with respect to polynomial time programming. This means, both that every well-typed Pola program is guaranteed to halt in time polynomial with respect to the size of its input, and that all such polynomial time functions can be written in Pola. The system supports a wide range of inductive and (higher-order) coinductive data types and a form of safe recursion is used to limit the power of programming with the inductive types. Examples will be given to illustrate both the programming style of Pola and how Pola's type system maintains polynomial complexity. -- Gillman Payette Department of Philosophy University of Calgary 2500 University Drive NW Calgary, AB T2N 1N4, Canada Ph 403.220.6463 Fax 403.289.5698 From rzach at ucalgary.ca Mon Mar 16 09:40:31 2009 From: rzach at ucalgary.ca (Richard Zach) Date: Mon Mar 16 09:41:35 2009 Subject: [Alta-Logic] Logic Miniconference March 27, 28 (Antonelli, Belnap, Segerberg) Message-ID: <1237218031.13485.22.camel@mx80> The Department of Philosophy will host a miniconference on logic on Friday March 27 and Saturday March 28. I'm thinking of ordering in lunch: could you please send me a brief email if you're planning on attending the Saturday sessions? The talks will be: Nuel Belnap (Pittsburg) Truth Values, Neither-True-Nor-False, and Supervaluations Friday March 27, 4pm Krister Segerberg (Uppsala/Calgary) Three Deontic Paradoxes Saturday March 28, 10 am Aldo Antonelli (UC Davis) Free Quantification and Logical Invariance Saturday March 28, 2pm All talks in 1253 Social Sciences From rzach at ucalgary.ca Tue Mar 24 10:51:47 2009 From: rzach at ucalgary.ca (Richard Zach) Date: Tue Mar 24 10:52:02 2009 Subject: [Alta-Logic] Logic Miniconference This Weekend (Belnap, Segerberg, Antonelli) Message-ID: <1237913507.28622.52.camel@mx80> Logic Miniconference Abstracts All Talks in 1243 Social Sciences, University of Calgary Relevant papers may be found by following the links below Nuel Belnap - Pittsburgh Friday, March 27, 4 pm "Truth Values, Neither-True-Nor-False, and Supervaluations" My oral remarks are based on an essay to appear in Studia Logica. (The essay evidently has more sections that I can adequately treat in the time allotted.) The first section defends reliance on truth values against those who, on nominalistic grounds, would uniformly substitute a truth predicate. I rehearse with great brevity some practical, Carnapian advantages of working with truth values in logic. In the second section, after introducing the key idea of "auxiliary parameters," I look at several cases in which logics involve, as part of their semantics, an extra auxiliary parameter to which truth is relativized, a parameter that caters to special kinds of sentences. In many cases, this facility is said to produce truth values for sentences that on the face of it seem neither true nor false. Often enough, in this situation appeal is made to the method of supervaluations, which operate by "quantifying out" auxiliary parameters, and thereby produce something like a truth value. Logics of this kind exhibit striking differences. I first consider the role that Tarski gives to supervaluation in first order logic, and then, after an interlude that asks whether neither-true-nor-false is itself a truth value. I consider sentences with non-denoting terms, vague sentences, ambiguous sentences, paradoxical sentences, and future-tensed sentences in indeterministic tense logic, I conclude my survey with a look at alethic modal logic considered as a cousin, and finish with a little "advice to supervaluationists," advice that is largely negative. The case for supervaluations as a road to truth is strong only when the auxiliary parameter that is "quantified out" is in fact irrelevant to the sentences of interest--as in Tarski's definition of 'truth' for classical logic. In all other cases, the best policy when reporting the results of supervaluation is to use only explicit phrases such as "settled true" or "determinately true," never dropping the qualification. http://www.phil.ucalgary.ca/philosophy/node/410 Krister Segerberg - Uppsala/Calgary Saturday, March 28, 10 am Three Deontic Paradoxes I am trying to develop a dynamic deontic logic, the outlines of which I will sketch. To motivate this attempt, and also to assess its merits, I will consider three classic paradoxes:  those due to Chisholm, Ross, and Forrester. Aldo Antonelli - California at Davis Saturday, March 28, 2 pm Free Quantification and Logical Invariance In order to present the problem of providing a natural and well-behaved semantics for (positive) free logic, a number of approaches are considered, some old, some new -- all of which are found wanting in some respect or other. We then shift our perspective in order to tackle the problem from the standpoint of the theory of generalized quantifiers, with accompanying emphasis on permutation invariance as a characteristic feature of logical notions. This will finally result in a natural and well-motivated semantic theory for positive free logic -- which, however, also leads to questioning the logical nature of free quantification. http://www.phil.ucalgary.ca/philosophy/node/493 From rzach at ucalgary.ca Tue Mar 24 11:07:56 2009 From: rzach at ucalgary.ca (Richard Zach) Date: Tue Mar 24 11:08:17 2009 Subject: [Alta-Logic] Dinner with Logicians? Message-ID: <1237914476.28622.77.camel@mx80> Dear Logicians and Logic-Interested Folks, There will be dinners with the logic miniconference speakers on Thursday, Friday, and Saturday. Please let me know if you'll be joining us, and for which evening(s). Graduate students and students in the modal logic seminar are especially welcome (meals will be free or subsidized depending on number of students coming!). Please let me know this by tomorrow (Wednesday) noon. I'll order in lunch on Saturday, so if you're attending and haven't yet sent me an email to that effect, please do so now. So far I have rsvp's only from: Steve Coyne Ali Kazmi Yosh Kobasigawa Teresa Kouri Jack Macintosh Gillman Payette Brian Redmond Jon Seldin Nicole Wyatt From ggpayett at ucalgary.ca Fri May 15 16:58:22 2009 From: ggpayett at ucalgary.ca (Gillman Payette) Date: Fri May 15 17:01:35 2009 Subject: [Alta-Logic] Tak on the 27th. Message-ID: <4136.75.158.233.235.1242428302.squirrel@75.158.233.235> This talk looks very interesting to those working in modal logic and multi-agent systems. Start: 05/27/2009 - 14:00 End: 05/27/2009 - 15:00 Room: ICT 616 Speaker: Mehrnoosh Sadrzadeh (joint work with Roy Dyckhoff) Abstract: We consider a simple modal logic whose non-modal part has conjunction and disjunction as connectives and whose modalities come in adjoint pairs, but are not in general closure operators. Despite absence of negation and implication, and of axioms corresponding to the characteristic axioms of (e.g.) T, S4 and S5, such logics are useful, as shown in previous work by Baltag, Coecke and Sadrzadeh, for encoding and reasoning about information and misinformation in multi-agent systems. For such a logic we present an algebraic semantics, using lattices with agent-indexed families of adjoint pairs of operators, and a cut-free sequent calculus. The calculus exploits operators on sequents, in the style of ``nested'' or ``tree-sequent'' calculi; cut-admissibility is shown by constructive syntactic methods. The applicability of the logic is illustrated by reasoning about the muddy children puzzle, for which the calculus is augmented with extra rules to express the facts of the muddy children scenario. -- Mehrnoosh Sadrzadeh EPSRC Postdoctoral Research Fellow Oxford University Computing Laboratory Research Fellow of Wolfson College http://web.comlab.ox.ac.uk/people/Mehrnoosh.Sadrzadeh/ -- Gillman Payette Department of Philosophy University of Calgary 2500 University Drive NW Calgary, AB T2N 1N4, Canada Ph 403.220.6463 Fax 403.289.5698 From ggpayett at ucalgary.ca Fri May 15 16:59:17 2009 From: ggpayett at ucalgary.ca (Gillman Payette) Date: Fri May 15 17:01:36 2009 Subject: [Alta-Logic] Tak on the 27th. Message-ID: <4137.75.158.233.235.1242428357.squirrel@75.158.233.235> This talk looks very interesting to those who have an interest in modal logic and/or multi-agent systems. Start: 05/27/2009 - 14:00 End: 05/27/2009 - 15:00 Room: ICT 616 Speaker: Mehrnoosh Sadrzadeh (joint work with Roy Dyckhoff) Abstract: We consider a simple modal logic whose non-modal part has conjunction and disjunction as connectives and whose modalities come in adjoint pairs, but are not in general closure operators. Despite absence of negation and implication, and of axioms corresponding to the characteristic axioms of (e.g.) T, S4 and S5, such logics are useful, as shown in previous work by Baltag, Coecke and Sadrzadeh, for encoding and reasoning about information and misinformation in multi-agent systems. For such a logic we present an algebraic semantics, using lattices with agent-indexed families of adjoint pairs of operators, and a cut-free sequent calculus. The calculus exploits operators on sequents, in the style of ``nested'' or ``tree-sequent'' calculi; cut-admissibility is shown by constructive syntactic methods. The applicability of the logic is illustrated by reasoning about the muddy children puzzle, for which the calculus is augmented with extra rules to express the facts of the muddy children scenario. -- Mehrnoosh Sadrzadeh EPSRC Postdoctoral Research Fellow Oxford University Computing Laboratory Research Fellow of Wolfson College http://web.comlab.ox.ac.uk/people/Mehrnoosh.Sadrzadeh/ -- Gillman Payette Department of Philosophy University of Calgary 2500 University Drive NW Calgary, AB T2N 1N4, Canada Ph 403.220.6463 Fax 403.289.5698 From rzach at ucalgary.ca Thu Oct 1 22:05:31 2009 From: rzach at ucalgary.ca (Richard Zach) Date: Thu Oct 1 22:05:39 2009 Subject: [Alta-Logic] Two Talks by Saul Kripke (Oct 13, 14) Message-ID: <1254456331.16993.31.camel@mx80> For the non-philosophers: Kripke is widely considered to be the most important 20th century analytic philosopher still living. A recent poll even had him ranked the 7th most influential philosopher of the last 200 years. He is best known for his work in logic (he developed semantics for modal logics--the now so-called "Kripke semantics"--when still a teenager, worked on theories of truth, Wittgenstein, and metaphysics and philosophy of language). He will give two talks at the University of Calgary in the week after next. The second of these, on David Hilbert's proof-theoretic program for the foundations of mathematics should be of interest especially also to mathematicians. Saul Kripke - The Structure of Possible Worlds: Some Considerations Tues Oct 13, 2:00 pm, Science Theatres, Room 127 Saul Kripke - The Trouble with the Hilbert Program Weds Oct 14, 4:00 pm, Science Theatres Room 145 From gscruttw at ucalgary.ca Mon Oct 5 15:30:12 2009 From: gscruttw at ucalgary.ca (gscruttw@ucalgary.ca) Date: Mon Oct 5 15:31:41 2009 Subject: [Alta-Logic] Two Talks on P-Time Computation Message-ID: This Wednesday, October 7th, we will have two talks on a language for polynomial-time computations. The talks will be from 10am-12 in ICT 616. Abstracts: Mike Burrell: Bounds inference in Pola Pola is a programming language in which every well-typed program runs in polynomial time. This opens up the possibility to automated inference of running time of a particular function. I'll talk about the most recent attempt to infer tight bounds for both inductive and coinductive data types. Brian Redmond: Pola's Type System Pola is a language for PTIME computations, which means that programs are both polynomial time and space bounded. In this talk, I will discuss Pola's type system, and a simple extension which maintains the polynomial space bound but allows for an encoding of a PSPACE complete problem. From ggpayett at ucalgary.ca Mon Oct 5 19:45:55 2009 From: ggpayett at ucalgary.ca (Gillman Payette) Date: Mon Oct 5 19:46:04 2009 Subject: [Alta-Logic] Talk on the 28th? Message-ID: <952f86ca263222a3edbb5093e24b64bf.squirrel@webmail.ucalgary.ca> Please check out the link below to respond to the poll to let me know what the most convenient time and place (You are given two options for time and two for place) is for you to attend a talk on the 28th of October. http://www.doodle.com/5kwk7ih8qw8susv4 -- Gillman Payette Department of Philosophy University of Calgary 2500 University Drive NW Calgary, AB T2N 1N4, Canada Ph 403.220.6463 Fax 403.289.5698 From rzach at ucalgary.ca Thu Oct 15 10:52:27 2009 From: rzach at ucalgary.ca (Richard Zach) Date: Thu Oct 15 10:52:46 2009 Subject: [Alta-Logic] Kripke talk Message-ID: <1255625547.27400.1.camel@debbie> Hi, Ali asked me to give a little presentation on what Kripke was talking about in his talk yesterday on Goedel and the Hilbert program. I was thinking Tuesday afternoon, say at 4. But I can do it some other time, if a lot of non-philosophers would like to come but don't have time then. Let me know. Best, R From rzach at ucalgary.ca Thu Oct 15 15:26:03 2009 From: rzach at ucalgary.ca (Richard Zach) Date: Thu Oct 15 15:26:07 2009 Subject: [Alta-Logic] Kripke talk In-Reply-To: <1255625547.27400.1.camel@debbie> References: <1255625547.27400.1.camel@debbie> Message-ID: <1255641963.27400.2.camel@debbie> Ok, two people can't make next week, and I have one request for earlier (3:30). So Tuesday October 26 at 3:30? -R On Thu, 2009-10-15 at 10:52 -0600, Richard Zach wrote: > Hi, > > Ali asked me to give a little presentation on what Kripke was talking > about in his talk yesterday on Goedel and the Hilbert program. I was > thinking Tuesday afternoon, say at 4. But I can do it some other time, > if a lot of non-philosophers would like to come but don't have time > then. Let me know. > > Best, > R > > _______________________________________________ > This message was sent to all subscribers of alta-logic-l > To unsubscribe, see instructions at: > http://www.ucalgary.ca/it/email/mailman > > E-mail: alta-logic-l@mailman.ucalgary.ca > Homepage: http://mailman.ucalgary.ca/mailman/listinfo/alta-logic-l > > From gscruttw at ucalgary.ca Mon Oct 19 09:29:53 2009 From: gscruttw at ucalgary.ca (gscruttw@ucalgary.ca) Date: Mon Oct 19 09:29:57 2009 Subject: [Alta-Logic] Combinatorial Game Categories Message-ID: <0dd67c83644a0238a631ed5596ff920d.squirrel@webmail.ucalgary.ca> This week (Wed, Oct. 21) I'll be talking about some work-in-progress on developing a theory of categories of combinatorial games. This will be an introductory talk: I'll discuss what combinatorial games are, and why it would be useful to have a theory of categories of combinatorial games. The talk will be in ICT 616 at 10am. - Geoff Cruttwell From gscruttw at ucalgary.ca Tue Oct 20 11:05:26 2009 From: gscruttw at ucalgary.ca (gscruttw@ucalgary.ca) Date: Tue Oct 20 11:05:31 2009 Subject: [Alta-Logic] Combinatorial Game Categories: Update: New Time In-Reply-To: <0dd67c83644a0238a631ed5596ff920d.squirrel@webmail.ucalgary.ca> References: <0dd67c83644a0238a631ed5596ff920d.squirrel@webmail.ucalgary.ca> Message-ID: Hi - The start time for tomorrow's talk will be 10:30 (rather than 10:00 as mentioned below). The room is still the same - ICT 616. - Geoff Cruttwell > This week (Wed, Oct. 21) I'll be talking about some work-in-progress on > developing a theory of categories of combinatorial games. This will be > an > introductory talk: I'll discuss what combinatorial games are, and why it > would be useful to have a theory of categories of combinatorial games. > > The talk will be in ICT 616 at 10am. > > - Geoff Cruttwell > > _______________________________________________ > This message was sent to all subscribers of alta-logic-l > To unsubscribe, see instructions at: > http://www.ucalgary.ca/it/email/mailman > > E-mail: alta-logic-l@mailman.ucalgary.ca > Homepage: http://mailman.ucalgary.ca/mailman/listinfo/alta-logic-l > > > From ggpayett at ucalgary.ca Fri Oct 23 19:25:21 2009 From: ggpayett at ucalgary.ca (Gillman Payette) Date: Fri Oct 23 19:25:25 2009 Subject: [Alta-Logic] Logic Talk on the 28th Message-ID: <1e19524eeb1007c3cefbe68ec3be0ce3.squirrel@webmail.ucalgary.ca> Start: 10/28/2009 - 14:00 End: 10/28/2009 - 15:00 Speaker: Peter K. Schotch, Dalhousie University (Philosophy) Place: SS 1253 (It is the seminar room in the Philosophy Department) Abstract: >From its earliest beginnings in the nineteenth Century, the algebra of logic has taken as its central focus, the notion of a finitary operation. These operations correspond in an obvious way with what the logicians call connectives. As advances have been made in what we now call abstract algebra, there has been no corresponding increase in the generality of the algebra of logic. Even when we consider algebra at its most abstract, category theory, we and that those who attempt to apply that lore to logic end up focusing on the operations no less than Boole himself did. This seems a shame in more ways than one. In the first place, by not attempting to do something a bit more general, practitioners of the algebra of logic seem to be committed to an anti-pluralist philosophy of logic whether or not they have ever given the matter much (or any) thought. This harsh criticism must be tempered a bit, when we consider the case of topos theory. In that particular branch of category theory, we can represent both intuitionistic logic and classical logic. This can be no better than a kind of limiting case of pluralism one cannot help but feel. One observes that the subobject classifier of a topos must be a Heyting algebra at which point it's back to operations again. Another reason to deplore the view which takes the operations as central, is that one misses entirely the chance to explain the connectives. The opportunity cost here is rather high, since the usual explanations in logic textbooks `explains' the connectives in terms of a supposed deep connection with certain words in natural language. It isn't hard to show that such an account is wrong, perhaps even wrong root and branch, or at least to show that logic has rather less to do with natural language than is dreamed of in most introductory logic texts. In this essay we attempt to use category theory as the algebra of logic, but in a way that seems more helpful to logic as well as more in the categorical spirit. This means that instead of treating some fixed logic as if it were a category, we shall take the notion of a logic to be defined quite generally and then define, for each in a large class of logics, what we call the associated logical category. In this category we can define certain familiar limits which do duty for the connectives conjunction and disjunction. This much is a bit old hat. We also show that the familiar limits (and colimits) exist in a wider sense than is usually considered. In terms of these limits we may obtain the allusive limit definition of a generalized form of negation. Finally, we make some remarks about how modality might be introduced in these new categories, functorially. -- Gillman Payette Department of Philosophy University of Calgary 2500 University Drive NW Calgary, AB T2N 1N4, Canada Ph 403.220.6463 Fax 403.289.5698 From rzach at ucalgary.ca Mon Oct 26 19:02:00 2009 From: rzach at ucalgary.ca (Richard Zach) Date: Mon Oct 26 19:02:07 2009 Subject: [Alta-Logic] Kripke talk In-Reply-To: <1255641963.27400.2.camel@debbie> References: <1255625547.27400.1.camel@debbie> <1255641963.27400.2.camel@debbie> Message-ID: <1256605320.27659.30.camel@delia> Hi again, Won't be ready by tomorrow and didn't manage to announce it anyway, so I'll postpone the "comments on Kripke's talk" talk to next week Tuesday Nov 3 at 3:30. -R From ggpayett at ucalgary.ca Wed Oct 28 10:23:39 2009 From: ggpayett at ucalgary.ca (Gillman Payette) Date: Wed Oct 28 10:24:02 2009 Subject: [Alta-Logic] Logic Talk today: reminder Message-ID: <00d1e8c233f7b6d2fa6e6d14ec5f7806.squirrel@webmail.ucalgary.ca> Start: 10/28/2009 - 14:00 End: 10/28/2009 - 15:00 Speaker: Peter K. Schotch, Dalhousie University (Philosophy) Place: SS 1253 (It is the seminar room in the Philosophy Department) Abstract: >From its earliest beginnings in the nineteenth Century, the algebra of logic has taken as its central focus, the notion of a finitary operation. These operations correspond in an obvious way with what the logicians call connectives. As advances have been made in what we now call abstract algebra, there has been no corresponding increase in the generality of the algebra of logic. Even when we consider algebra at its most abstract, category theory, we and that those who attempt to apply that lore to logic end up focusing on the operations no less than Boole himself did. This seems a shame in more ways than one. In the first place, by not attempting to do something a bit more general, practitioners of the algebra of logic seem to be committed to an anti-pluralist philosophy of logic whether or not they have ever given the matter much (or any) thought. This harsh criticism must be tempered a bit, when we consider the case of topos theory. In that particular branch of category theory, we can represent both intuitionistic logic and classical logic. This can be no better than a kind of limiting case of pluralism one cannot help but feel. One observes that the subobject classifier of a topos must be a Heyting algebra at which point it's back to operations again. Another reason to deplore the view which takes the operations as central, is that one misses entirely the chance to explain the connectives. The opportunity cost here is rather high, since the usual explanations in logic textbooks `explains' the connectives in terms of a supposed deep connection with certain words in natural language. It isn't hard to show that such an account is wrong, perhaps even wrong root and branch, or at least to show that logic has rather less to do with natural language than is dreamed of in most introductory logic texts. In this essay we attempt to use category theory as the algebra of logic, but in a way that seems more helpful to logic as well as more in the categorical spirit. This means that instead of treating some fixed logic as if it were a category, we shall take the notion of a logic to be defined quite generally and then define, for each in a large class of logics, what we call the associated logical category. In this category we can define certain familiar limits which do duty for the connectives conjunction and disjunction. This much is a bit old hat. We also show that the familiar limits (and colimits) exist in a wider sense than is usually considered. In terms of these limits we may obtain the allusive limit definition of a generalized form of negation. Finally, we make some remarks about how modality might be introduced in these new categories, functorially. -- Gillman Payette Department of Philosophy University of Calgary 2500 University Drive NW Calgary, AB T2N 1N4, Canada Ph 403.220.6463 Fax 403.289.5698 -- Gillman Payette Department of Philosophy University of Calgary 2500 University Drive NW Calgary, AB T2N 1N4, Canada Ph 403.220.6463 Fax 403.289.5698 From ggpayett at ucalgary.ca Wed Oct 28 13:20:01 2009 From: ggpayett at ucalgary.ca (Gillman Payette) Date: Wed Oct 28 13:20:16 2009 Subject: [Alta-Logic] talk today Message-ID: <5d471dc30032382d9da934bd20754bfa.squirrel@webmail.ucalgary.ca> The talk today will be starting a little late. -- Gillman Payette Department of Philosophy University of Calgary 2500 University Drive NW Calgary, AB T2N 1N4, Canada Ph 403.220.6463 Fax 403.289.5698 From rzach at ucalgary.ca Thu Oct 29 10:13:57 2009 From: rzach at ucalgary.ca (Richard Zach) Date: Thu Oct 29 10:14:02 2009 Subject: [Alta-Logic] Recap: Kripke on Hilbert's Program Message-ID: <1256832837.22544.2.camel@debbie> Next Tuesday, November 3, I'll say a few things by way of recap and explanation of Kripke's second lecture. It'll be in 1253 SS at 3:30. -R From robin at ucalgary.ca Thu Nov 12 14:56:33 2009 From: robin at ucalgary.ca (Robin Cockett) Date: Thu Nov 12 18:23:27 2009 Subject: [Alta-Logic] Computer Science Invited Speaker - Pavel Hrubes November 23rd, 2009 at 12pm in ICT 616 Message-ID: <4AFC8491.3050402@ucalgary.ca> Pavel Hrubes is visiting the university for Monday/Tuesday 23/24 November. We will be going to lunch with him after his talk if you wish to join us please do! Invited Speaker *** "Non-Commutative Arithmetic Circuits and the Sum of Squares Problem" ** presented by Pavel Hrubes **/ Hosted by Theory Group /* *Date:* Monday, November 23, 2009 *Time:* 12:00pm *Location: *ICT 616 *Abstract:* The arithmetic circuit is a basic model for computing polynomials over a given field. In a non-commutative polynomial, variables do not multiplicatively commute; one can think of the variables as representing matrices. I will discuss non-commutative arithmetic circuits, which compute non-commutative polynomials. The major open question is to prove a superpolynomial lower bound on the size of a circuit computing an explicit non-commutative polynomial. This question is related to a classical mathematical problem, the so called sum of squares problem. This problem lies on the boundary of algebra and topology, and is interesting from a purely mathematical point of view. I will sketch the connection between non-commutative arithmetic circuits and sum of squares, and proceed to discuss mathematical aspects of the sum of squares problem. (Joint work with Amir Yehudayoff and Avi Wigderson.) *Biography:* Pavel Hrubes received his Ph.D. in mathematics in 2007 from the Charles University in Prague. Afterwards he became a postdoctoral fellow at the University of Toronto, and since 2008 he has been a postdoctoral fellow at the Institute for Advanced Study in Princeton. From gscruttw at ucalgary.ca Mon Nov 23 13:36:37 2009 From: gscruttw at ucalgary.ca (gscruttw@ucalgary.ca) Date: Mon Nov 23 13:36:56 2009 Subject: [Alta-Logic] Series on T-monoids and 2-dimensional category theory Message-ID: <43ca5adbe51656e97c539077bce5fe6e.squirrel@webmail.ucalgary.ca> This Wednesday, Nov. 25, I'll be starting a series of talks. The goal is to get to a result of Mike Schulman's and I on how a great number of mathematical objects can be constructed in the same way, by using the "construction of T-monoids". Examples of such constructed objects include topological spaces, metric spaces, rings, algebras, enriched categories, internal categories, and "generalized multicategories". The talks are also, however, an introduction to 2-dimensional category theory: the use of 2-categories, bicategories, and double categories. The hope is that only knowledge of basic category theory will be needed to follow the talks. The series will consist of: I: Enriched Categories, Internal Categories, and 2-categories II: Double Categories and the "Monoids and Modules" Construction III: Virtual Double Categories and the "T-monoids and modules" construction The talks will be on Wednesdays, 12-1pm. The first one will be in ICT 616, this Wednesday Nov. 25. - Geoff Cruttwell From rzach at ucalgary.ca Tue Nov 24 22:04:41 2009 From: rzach at ucalgary.ca (Richard Zach) Date: Tue Nov 24 22:04:52 2009 Subject: [Alta-Logic] Party: December 12 Message-ID: <1259125481.10458.38.camel@delia> Start Time: Saturday, December 12, 2009 at 8:00pm End Time: Sunday, December 13, 2009 at 4:00am Location: Elizabeth and Richard's House Street: 1411 1 Ave NW City/Town: Calgary, AB Map: http://maps.google.com/maps?f=q&hl=en&q=1411+1+Ave+NW%2C+Calgary%2C+AB Another semester is drawing to a close, so it's time for a holiday party. We will throw one on Saturday, December 12, at party time. There is a fashion theme: Mad Men (it's a TV show: http://www.amctv.com/originals/madmen/). But as always, party spirit is more important than party attire, so don't stay away just because you don't have a 60s dress or suit. We certainly won't stick to the theme when it comes to the music. Bring your s.o., something you'd like to drink, your friends, and, if you like, music (we can play everything except 8-track). For directions or RSVP: Elizabeth: brake@ucalgary.ca, or 403-283-3643 Richard: rzach@ucalgary.ca, or 403-383-0377 Or RSVP on facebook: http://www.facebook.com/event.php?eid=209554340140 From gscruttw at ucalgary.ca Wed Nov 25 10:08:47 2009 From: gscruttw at ucalgary.ca (gscruttw@ucalgary.ca) Date: Wed Nov 25 10:08:54 2009 Subject: [Alta-Logic] Reminder: Talk Today Message-ID: <7493226f342615ea83d004fe07323a92.squirrel@webmail.ucalgary.ca> This is just a reminder of today's talk from 12-1 in ICT 616: This Wednesday, Nov. 25, I'll be starting a series of talks. The goal is to get to a result of Mike Schulman's and I on how a great number of mathematical objects can be constructed in the same way, by using the "construction of T-monoids". Examples of such constructed objects include topological spaces, metric spaces, rings, algebras, enriched categories, internal categories, and "generalized multicategories". The talks are also, however, an introduction to 2-dimensional category theory: the use of 2-categories, bicategories, and double categories. The hope is that only knowledge of basic category theory will be needed to follow the talks. The series will consist of: I: Enriched Categories, Internal Categories, and 2-categories II: Double Categories and the "Monoids and Modules" Construction III: Virtual Double Categories and the "T-monoids and modules" construction The talks will be on Wednesdays, 12-1pm. The first one will be in ICT 616, this Wednesday Nov. 25. - Geoff Cruttwell From gscruttw at ucalgary.ca Wed Nov 25 15:18:52 2009 From: gscruttw at ucalgary.ca (gscruttw@ucalgary.ca) Date: Wed Nov 25 15:19:15 2009 Subject: [Alta-Logic] Notes for today's talk Message-ID: If you missed the talk today and would like notes, I have put them up at: http://pages.cpsc.ucalgary.ca/~gscruttw/ I will probably keep these updated as the talks continue. - Geoff From gscruttw at ucalgary.ca Mon Nov 30 11:58:33 2009 From: gscruttw at ucalgary.ca (gscruttw@ucalgary.ca) Date: Mon Nov 30 11:58:55 2009 Subject: [Alta-Logic] Continuing Series: Internal Categories Message-ID: <6fbb9eea32c8742a27ec2d8153cf210f.squirrel@webmail.ucalgary.ca> Last time, I talked about how "enriched categories" generalize one definition of category: the hom-set definition. This time, we'll talk about how to generalize the "set of arrows" definition, giving internal categories. As before, we'll look at a number of interesting examples, in this case mostly related to topological applications. The talk will be this Wednesday, Dec. 2nd, in the same room as last time - ICT 616. As previously mentioned, the notes for last week's talk are at http://pages.cpsc.ucalgary.ca/~gscruttw/ and will be continued after this week's talk. - Geoff From gscruttw at ucalgary.ca Mon Nov 30 15:42:00 2009 From: gscruttw at ucalgary.ca (gscruttw@ucalgary.ca) Date: Mon Nov 30 15:42:20 2009 Subject: [Alta-Logic] Continuing Series: Internal Categories In-Reply-To: <6fbb9eea32c8742a27ec2d8153cf210f.squirrel@webmail.ucalgary.ca> References: <6fbb9eea32c8742a27ec2d8153cf210f.squirrel@webmail.ucalgary.ca> Message-ID: <7ba568764b8f3cb20343f5715eb271f0.squirrel@webmail.ucalgary.ca> I forgot to mention the time. It's the same as last week: 12-1pm. - Geoff > Last time, I talked about how "enriched categories" generalize one > definition of category: the hom-set definition. This time, we'll talk > about how to generalize the "set of arrows" definition, giving internal > categories. As before, we'll look at a number of interesting examples, > in > this case mostly related to topological applications. > > The talk will be this Wednesday, Dec. 2nd, in the same room as last time > - > ICT 616. > > As previously mentioned, the notes for last week's talk are at > http://pages.cpsc.ucalgary.ca/~gscruttw/ > and will be continued after this week's talk. > > - Geoff > > _______________________________________________ > This message was sent to all subscribers of alta-logic-l > To unsubscribe, see instructions at: > http://www.ucalgary.ca/it/email/mailman > > E-mail: alta-logic-l@mailman.ucalgary.ca > Homepage: http://mailman.ucalgary.ca/mailman/listinfo/alta-logic-l > > > From gscruttw at ucalgary.ca Wed Dec 2 09:51:36 2009 From: gscruttw at ucalgary.ca (gscruttw@ucalgary.ca) Date: Wed Dec 2 09:51:59 2009 Subject: [Alta-Logic] Reminder: Seminar Today Message-ID: In ICT 616, 12-1 pm: Last time, I talked about how "enriched categories" generalize one definition of category: the hom-set definition. This time, we'll talk about how to generalize the "set of arrows" definition, giving internal categories. As before, we'll look at a number of interesting examples, in this case mostly related to topological applications. As previously mentioned, the notes for last week's talk are at http://pages.cpsc.ucalgary.ca/~gscruttw/ and will be continued after this week's talk. - Geoff From gscruttw at ucalgary.ca Wed Dec 2 15:59:28 2009 From: gscruttw at ucalgary.ca (gscruttw@ucalgary.ca) Date: Wed Dec 2 15:59:53 2009 Subject: [Alta-Logic] Notes for today's talk Message-ID: The notes from last time have been updated to include today's seminar, and can be found at: http://pages.cpsc.ucalgary.ca/~gscruttw/ - Geoff Cruttwell From gscruttw at ucalgary.ca Tue Dec 8 09:18:28 2009 From: gscruttw at ucalgary.ca (gscruttw@ucalgary.ca) Date: Tue Dec 8 09:18:33 2009 Subject: [Alta-Logic] Talk Tomorrow: Continuing Series: 2-categories Message-ID: Tomorrow, 12-1pm in ICT 616, I will continue my series. Previously, we have looked at enriched categories and internal categories. This time, we'll look at how these structures are organized. The guiding structure is that of a 2-category; a structure with objects, arrows, and arrows-between-arrows. From gscruttw at ucalgary.ca Wed Dec 9 10:08:45 2009 From: gscruttw at ucalgary.ca (gscruttw@ucalgary.ca) Date: Wed Dec 9 10:08:53 2009 Subject: [Alta-Logic] Reminder: Talk Today: Continuing Series: 2-categories In-Reply-To: References: Message-ID: <43b3657e7019a490657eb3bb88ff4657.squirrel@webmail.ucalgary.ca> This is a reminder that this talk is today from 12-1 pm in ICT 616. > Tomorrow, 12-1pm in ICT 616, I will continue my series. Previously, we > have looked at enriched categories and internal categories. This time, > we'll look at how these structures are organized. The guiding structure > is that of a 2-category; a structure with objects, arrows, and > arrows-between-arrows. > > _______________________________________________ > This message was sent to all subscribers of alta-logic-l > To unsubscribe, see instructions at: > http://www.ucalgary.ca/it/email/mailman > > E-mail: alta-logic-l@mailman.ucalgary.ca > Homepage: http://mailman.ucalgary.ca/mailman/listinfo/alta-logic-l > > >