Olá Dória,
não sei o que o Tony quer dizer com isso, mas o assunto de fibrilação de lógicas (fibring} e muito mais sobre combinações de lógicas é o tema do nosso livro: W. A. Carnielli, M. E. Coniglio, D. Gabbay, P. Gouveia and C. Sernadas. Analysis and Synthesis of Logics. How to Cut and Paste Reasoning Systems. Applied Logic Series, Springer, 2008. Talvez para começar fosse bom ver nossa entrada: W. A. Carnielli and M. E. Coniglio. Combining Logics. Stanford Encyclopedia of Philosophy, 2007. http://plato.stanford.edu/entries/logic-combining/ A entrada foi recentemente revisada (na semana passada) mas eles ainda não colocaram a nova versão no ar. Contudo, a antiga, apesar de algumas imprecisões, dá para dar uma boa ideia. Abraços, Walter Em 9 de outubro de 2011 20:38, Francisco Antonio Doria <famado...@gmail.com> escreveu: > Conheço fibração em geometria. Como é em lógica? > > 2011/10/9 Valeria de Paiva <valeria.depa...@gmail.com> > >> oi Tony, >> >We can look back at Goedel's work as one early attempt of fibring of >> formal systems. >> e', a gente sempre pode "look at anything as anything", mas qual 'e a >> sua evidencia de que isso 'e util? o que voce acha que ganha com essa >> interpretacao? >> >> obrigada, >> valeria >> >> 2011/10/1 Tony Marmo <marmo.t...@gmail.com>: >> > Dear friends, >> > >> > We can look back at Goedel's work as one early attempt of fibring of >> formal >> > systems. Thus, the problem of determining the consistency and the >> > completeness of the system seems to be like the same problem for a given >> > logic L which is obtained by the fibring of two logics L* and L**. First >> > order arithmetics is thus the fibring of first order logic and Peano's >> > arithmetics, which yields the known results presented by Goedel. >> > >> > We have no a priori intuitive reason to assume that a certain fibring >> will >> > produce a consistent and complete system. This has to be checked as the >> > systems are combined. If in combining two systems one produces results >> like >> > those of Goedel's theorems, it must still be possible to investigate the >> > resulting system by investigating other features of the same, namely >> > checking whether it has different, new, unusual or unexpected properties. >> > >> > In sum, I don't expect to see novelties that can or will overshadow >> Goedel's >> > contributions, except in consequence of more advances in the field of >> > fibring. >> > >> > Em 1 de outubro de 2011 14:21, Walter Carnielli >> > <walter.carnie...@gmail.com>escreveu: >> > >> >> Caros colegas: >> >> >> >> como vimos, o Ed Nelson retirou seu "claim" sobre a inconsistência de >> >> P. >> >> Isso, contudo, não significa o fim das discussões, nem menos a >> >> garantia da consistência de P! >> >> >> >> Quero aqui parabenizar ao nosso colega Daniel Tausk do IME USP >> >> (http://www.ime.usp.br/~tausk/) >> >> pela excelente observação que convenceu o Nelson. Imagino que o >> >> Rodrigo Freire e outros coelgas da USP tenham participado >> >> ativamente da atmosfera de discussão que levou o Daniel a observar o >> >> erro na pretensa prova do Ed Nelson. >> >> >> >> E finalmente parabenizo o Ed Nelosn pela coragem em propor sua >> >> alegação, e pela humildade em reconhecer publicamente o erro. Acho >> >> que é assim que se faz ciência, e acho que esse tipo de atitude é >> >> que devemos ensinar aos nossos estudantes, e aprendermos nós >> >> mesmos. Ed Nelson merece uma homegagem. >> >> >> >> Abraços, >> >> >> >> Walter >> >> >> >> ---------- Forwarded message ---------- >> >> From: Edward Nelson <nel...@math.princeton.edu> >> >> Date: 2011/10/1 >> >> Subject: [FOM] inconsistency of P >> >> To: f...@cs.nyu.edu >> >> >> >> >> >> Terrence Tao, at >> >> http://golem.ph.utexas.edu/category/2011/09/ >> >> and independently Daniel Tausk (private communication) >> >> have found an irreparable error in my outline. >> >> In the Kritchman-Raz proof, there is a low complexity >> >> proof of K(\bar\xi)>\ell if we assume \mu=1, but the >> >> Chaitin machine may find a shorter proof of high >> >> complexity, with no control over how high. >> >> >> >> My thanks to Tao and Tausk for spotting this. >> >> I withdraw my claim. >> >> >> >> The consistency of P remains an open problem. >> >> >> >> Ed Nelson >> >> _______________________________________________ >> >> FOM mailing list >> >> f...@cs.nyu.edu >> >> http://www.cs.nyu.edu/mailman/listinfo/fom >> >> >> >> >> >> >> >> -- >> >> ----------------------------------------------- >> >> Prof. Dr. Walter Carnielli >> >> Director >> >> Centre for Logic, Epistemology and the History of Science – CLE >> >> State University of Campinas –UNICAMP >> >> 13083-859 Campinas -SP, Brazil >> >> Phone: (+55) (19) 3521-6517 >> >> Fax: (+55) (19) 3289-3269 >> >> Institutional e-mail: walter.carnie...@cle.unicamp.br >> >> Website: http://www.cle.unicamp.br/prof/carnielli >> >> _______________________________________________ >> >> Logica-l mailing list >> >> Logica-l@dimap.ufrn.br >> >> http://www.dimap.ufrn.br/cgi-bin/mailman/listinfo/logica-l >> >> >> > _______________________________________________ >> > Logica-l mailing list >> > Logica-l@dimap.ufrn.br >> > http://www.dimap.ufrn.br/cgi-bin/mailman/listinfo/logica-l >> > >> >> >> >> -- >> Valeria de Paiva >> http://www.cs.bham.ac.uk/~vdp/ >> http://valeriadepaiva.org/www/ >> _______________________________________________ >> Logica-l mailing list >> Logica-l@dimap.ufrn.br >> http://www.dimap.ufrn.br/cgi-bin/mailman/listinfo/logica-l >> > > > > -- > fad > > ahhata alati, awienta Wilushati > _______________________________________________ > Logica-l mailing list > Logica-l@dimap.ufrn.br > http://www.dimap.ufrn.br/cgi-bin/mailman/listinfo/logica-l > -- ----------------------------------------------- Prof. Dr. Walter Carnielli Director Centre for Logic, Epistemology and the History of Science – CLE State University of Campinas –UNICAMP 13083-859 Campinas -SP, Brazil Phone: (+55) (19) 3521-6517 Fax: (+55) (19) 3289-3269 Institutional e-mail: walter.carnie...@cle.unicamp.br Website: http://www.cle.unicamp.br/prof/carnielli _______________________________________________ Logica-l mailing list Logica-l@dimap.ufrn.br http://www.dimap.ufrn.br/cgi-bin/mailman/listinfo/logica-l
