Dear Cheerful Logicians and Friends of Logic, There are three talks to announce this week: one each on Monday, Tuesday, and Friday. All the details below can be found on either the main calendar or the member groups calendar on the supergroup website, which you can find at https://sites.google.com/view/logicsupergroup/.
Details about all of these talks are also found below. Supergroup Talk Speaker: Stewart Shapiro (OSU/UConn) and David McCarty (Indiana) Title: Intuitionistic Sets and Numbers: the theory SST Time and Date: Friday, September 25 1000 GMT-5 Link: https://ksu.zoom.us/j/99006967120?pwd=bElXcUlUcUpLQkNHdER5Q2dobVN4dz09 *Meeting* ID: 990 0696 7120 *Passcode*: numbers Abstract: SST is a small intuitionistic set theory governing the hereditarily finite sets. It is based upon set induction. Simple as SST is, it seems remarkably strong: it deduces--within intuitionistic formal logic--all the axioms of ZF + AC, less the Axiom of Infinity, except that Separation is limited to decidable predicates. It is relatively straightforward to prove that SST has the usual Goedelian incompleteness properties. SST is definitionally equivalent to full, first-order intuitionistic arithmetic, aka Heyting Arithmetic. And SST manifests the attractive metamathematical properties of many intuitionistic mathematical theories--it supports a number of different realizability and topological interpretations and can be assumed to be categorical. Talks by Other Groups: *Logic and Metaphysics Workshop* (CUNY) *Speaker: *Yale Weiss (CUNY) *Title: *Arithmetical Semantics for Non-Classical Logic *Time and Date: *Monday, September 21 15:15 GMT-5 *Link: * https://gc-cuny.zoom.us/j/94449461647?pwd=dnNtVjhBN2tzcWZPNnJYSlliTFFDZz09 *Meeting ID: *944 4946 1647 *Passcode: *583887 *Abstract: *I consider logics which can be characterized exactly in the lattice of the positive integers ordered by division. I show that various (fragments of) relevant logics and intuitionistic logic are sound and complete with respect to this structure taken as a frame; different logics are characterized in it by imposing different conditions on valuations. This presentation will both cover and extend previous/forthcoming work of mine on the subject. *OCIE Seminar* Speaker: Bruno Bentzen (CMU) Title: Frege's Anticipation of Simple Type Theory Time and Date: Tuesday, September 22 18:00 GMT-5 Link: https://uci.zoom.us/j/95859575948 <https://www.google.com/url?q=https://uci.zoom.us/j/95859575948&sa=D&source=calendar&usd=2&usg=AOvVaw0cqEVqxn-Ly-ur0eXxkNAV> Abstract: In this talk, I argue that Frege's sharp distinction between terms denoting objects and terms denoting functions on the basis of their saturation anticipate a version of simple type theory, although Frege vacillates between regarding functions as closed terms of a function type and open terms formed under a hypothetical judgment. In the end, Frege fails to express his logical views consistently due to his logicist ambitions, which require him to endorse the view that value-ranges are objects. Other Notes and Announcements: - *The Logic Supergroup has a YouTube channel!* Recordings of almost all talks are available at https://www.youtube.com/channel/UCqOAS8SHP-5nGjYEE2FE6xw Yay for logic! -- Você está recebendo esta mensagem porque se inscreveu no grupo "LOGICA-L" dos Grupos do Google. Para cancelar inscrição nesse grupo e parar de receber e-mails dele, envie um e-mail para [email protected]. Para ver esta discussão na web, acesse https://groups.google.com/a/dimap.ufrn.br/d/msgid/logica-l/CAMTR9900NBkVBLPR3VkN9J4Kpn1DrO53BHbDdBiAtMiKuyuWDw%40mail.gmail.com.
