Things that can and things that can’t be done in PRA

Forfattere

  • Ulrich Kohlenbach

DOI:

https://doi.org/10.7146/brics.v5i18.19424

Resumé

It is well-known by now that large parts of (non-constructive) mathematical reasoning can be carried out in systems T 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 T ) and therefore go far beyond the strength of PRA (when added to T ).
In this paper we determine precisely the arithmetical and computational strength (in terms of optimal conservation results and subrecursive characterizations of provably recursive functions) of weaker function parameter-free schematic versions S− of S, thereby
exhibiting different levels of strength between these principles as well as a sharp borderline between fragments of analysis which are still conservative over PRA and extensions which just go beyond the strength of PRA.

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Publiceret

1998-01-18

Citation/Eksport

Kohlenbach, U. (1998). Things that can and things that can’t be done in PRA. BRICS Report Series, 5(18). https://doi.org/10.7146/brics.v5i18.19424

Nummer

Nr. 18 (1998): RS-18 Things that can and things that can’t be done in PRA

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Artikler

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