Things that can and things that can't be done in PRA
Ulrich Kohlenbach September 1998 |
Abstract:It is well-known by now that large parts of (non-constructive)
mathematical reasoning can be carried out in systems which are
conservative over primitive recursive arithmetic PRA (and even much
weaker systems). On the other hand there are principles S of elementary
analysis (like the Bolzano-Weierstraß principle, the existence of a limit
superior for bounded sequences etc.) which are known to be equivalent to
arithmetical comprehension (relative to ) and therefore go far
beyond the strength of PRA (when added to ). Available as PostScript, PDF, DVI. |