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Disjunction and existence under implication in elementary intuitionistic formalisms

Published online by Cambridge University Press:  12 March 2014

S. C. Kleene*
Affiliation:
The University of Wisconsin

Extract

Let Pp, Pd, and N be the intuitionistic formal systems of prepositional calculus, predicate calculus, and elementary number theory, respectively.1 Consider the following six propositions.8

(1) ├A V B only if ├A or ├B.

(2) ├∋xA(x) only if ├Ã(t) for some formula Ã(x) congruent to A(x) and some term t free for x in Ã(x).

Type
Research Article
Copyright
Copyright © Association for Symbolic Logic 1962

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References

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