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The optimality of induction as an axiomatization of arithmetic1

Published online by Cambridge University Press:  12 March 2014

Daniel Leivant*
Affiliation:
Department of Computer Science, Cornell University, Ithaca, New York 14853

Extract

By induction for a formula φ we mean the schema

(where the terms in brackets are implicitly substituted for some fixed variable, with the usual restrictions). Let be the schema IAφ for φ in Πn (i.e. ); similarly for . Each instance of is Δn+2, and each instance of is Σn+1 Thus the universal closure of an instance α is Πn+2 in either case. Charles Parsons [72] proved that and are equivalent over Z0, where Z0 is essentially Primitive Recursive Arithmetic augmented by classical First Order Logic [Parsons 70].

Theorem. For each n > 0 there is a Πn formula π for whichis not derivable in Z0from

(i) true Πn+1sentences; nor even

(ii) Πn+1sentences consistent withZ0.

Type
Research Article
Copyright
Copyright © Association for Symbolic Logic 1983

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Footnotes

1

Research supported in part by NSF grant 78–00418.

References

REFERENCES

[Kleene 52]Kleene, S.C., Introduction to metamathematics, Noordhoff, Groningen, 1952.Google Scholar
[Kreisel 65]Kreisel, G., Mathematical logic, Lectures on Modern Mathematics, Vol. III, (Saaty, T.L., Editor), Wiley, New York, 1965, pp. 95105.Google Scholar
[Kreisel-Wang 55]Kreisel, G. and Wang, H., Some applications of formalized consistency proofs, Fundamenta Mathematicae, vol. 42 (1955), pp. 101110.CrossRefGoogle Scholar
[Parsons 70]Parsons, Ch., On a number theoretic choice schema and its relation to induction, Intuitionism and Proof Theory (Kino, A., Myhill, J., Vesley, R.E., Editors), North-Holland, Amsterdam, 1970, pp. 459–174.Google Scholar
[Parsons 71]Parsons, Ch., On a number theoretic choice schema II (abstract), this Journal, vol. 36 (1971), p. 578.Google Scholar
[Parsons 72]Parsons, Ch., On n-quantifier induction, this Journal, vol. 37 (1972), pp. 466482.Google Scholar
[Smorynski 77]Smorynski, C., The incompleteness theorems, Handbook of Mathematic Logic (Barwise, J., Editor), North-Holland, Amsterdam, 1977, pp. 821866.CrossRefGoogle Scholar