Obrigado, Walter. Espaços fibrados aparecem muito em geometria, mas em lógica desconhecia o conceito.
Sent from my iPhone On 09/10/2011, at 09:53, Walter Carnielli <[email protected]> wrote: > 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 > <[email protected]> escreveu: >> Conheço fibração em geometria. Como é em lógica? >> >> 2011/10/9 Valeria de Paiva <[email protected]> >> >>> 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 <[email protected]>: >>>> 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 >>>> <[email protected]>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 <[email protected]> >>>>> Date: 2011/10/1 >>>>> Subject: [FOM] inconsistency of P >>>>> To: [email protected] >>>>> >>>>> >>>>> 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 >>>>> [email protected] >>>>> 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: [email protected] >>>>> Website: http://www.cle.unicamp.br/prof/carnielli >>>>> _______________________________________________ >>>>> Logica-l mailing list >>>>> [email protected] >>>>> http://www.dimap.ufrn.br/cgi-bin/mailman/listinfo/logica-l >>>>> >>>> _______________________________________________ >>>> Logica-l mailing list >>>> [email protected] >>>> 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 >>> [email protected] >>> http://www.dimap.ufrn.br/cgi-bin/mailman/listinfo/logica-l >>> >> >> >> >> -- >> fad >> >> ahhata alati, awienta Wilushati >> _______________________________________________ >> Logica-l mailing list >> [email protected] >> 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: [email protected] > Website: http://www.cle.unicamp.br/prof/carnielli _______________________________________________ Logica-l mailing list [email protected] http://www.dimap.ufrn.br/cgi-bin/mailman/listinfo/logica-l
