The next Logica Universalis Webinar session will take place September 28 at 4pm CET
Speaker: Tin Adlešic Title: A Modern Rigorous Approach to Stratification in NF/NFU Abstract: The main feature of NF/NFU is the notion of stratification, which sets it apart from other set theories. We define stratification and prove constructively that every stratified formula has the (unique) least assignment of types. The basic notion of stratification is concerned only with variables, but we extend it to abstraction terms in order to simplify further development. We reflect on nested abstraction terms, proving that they get the expected types. These extensions enable us to check whether some complex formula is stratified without rewriting it in the basic language. We also introduce natural numbers and a variant of the axiom of infinity, in order to precisely introduce type level ordered pairs, which are crucial in simplifying the definitions in the last part of the article. Using these notions we can easily define the sets of ordinal and cardinal numbers, which we show at the end of the article. The same approach can be readily applied to NF. https://link.springer.com/article/10.1007/s11787-022-00310-y Chair: Srecko Kovac https://www.ifzg.hr/~skovac/index_files/Page328.html Editorial Board LU Associate Organization: European Set Theory Society https://ests.wordpress.com/trustees-2022-2024/ presented by its president, Philip Welch https://en.wikipedia.org/wiki/Philip_Welch This session will take place during the 11th LAP in Dubrovnik The LAP series of logica events http://imft.ftn.uns.ac.rs/math/cms/LAP2022 will be presented by Zvonimir Šikić. To take part, register here: https://www.springer.com/journal/11787/updates/20065848 Jean-Yves Beziau Organizer of LUW and President of LUA http://www.logica-universalis.org/LUAD -- LOGICA-L Lista acadêmica brasileira dos profissionais e estudantes da área de Lógica <logica-l@dimap.ufrn.br> --- 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 logica-l+unsubscr...@dimap.ufrn.br. Para ver esta discussão na web, acesse https://groups.google.com/a/dimap.ufrn.br/d/msgid/logica-l/CAF2zFLDFmDTF6DAAVDd7cRvwRqio5oD-bM9r2HuecKo0M5qfCg%40mail.gmail.com.
