Atribución-NoComercial 4.0 InternacionalFeferman, Solomon2019-06-292019-06-291985https://repositorio.unal.edu.co/handle/unal/48761Several publications in recent years have presented various formal theories T in which considerable portions of mathematical practice (particularly analysis) can be more or less directly formalized and which are proof-theoretically weak; cf. Feferman 1977, Takeuti 1978 and Friedman 1980.application/pdfspaDerechos reservados - Universidad Nacional de Colombiahttp://creativecommons.org/licenses/by-nc/4.0/A theory of variable typesArtÃculo de revistahttp://bdigital.unal.edu.co/42218/info:eu-repo/semantics/openAccessvarious formal theoriesmathematical practiceparticularly analysis