The continuum as a formal space

Citation
S. Negri et D. Soravia, The continuum as a formal space, ARCH MATH L, 38(7), 1999, pp. 423-447
Citations number
37
Categorie Soggetti
Mathematics
Journal title
ARCHIVE FOR MATHEMATICAL LOGIC
ISSN journal
09335846 → ACNP
Volume
38
Issue
7
Year of publication
1999
Pages
423 - 447
Database
ISI
SICI code
0933-5846(199910)38:7<423:TCAAFS>2.0.ZU;2-C
Abstract
A constructive definition of the continuum based on formal topology is give n and its basic properties studied. A natural notion of Cauchy sequence is introduced and Cauchy completeness is proved. Other results include element ary proofs of the Baire and Canter theorems. From a classical standpoint, f ormal reals are seen to be equivalent to the usual reals. Lastly, the relat ion of real numbers as a formal space to other approaches to constructive r eal numbers is determined.