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Proof of the law of infinite conjunction using the perfect disjunctive normal form1
Published online by Cambridge University Press: 12 March 2014
Extract
The law of infinite conjunction (Quine's name, see Methods of logic, rev. ed., Holt & Co., New York, p. 254) says that a set of truthfunctional formulas is satisfiable provided every finite subset is. We give a proof of the law which uses some properties of the perfect disjunctive normal form.
Any satisfiable formula can be written as a disjunction of conjunctions of literals (a literal is a statement-letter or the negation of one) in which a statement-letter which occurs in any conjunction occurs exactly once in each; a literal by itself counts as a conjunction and a conjunction by itself as a disjunction.
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- Research Article
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- Copyright
- Copyright © Association for Symbolic Logic 1967
Footnotes
I would like to thank Professor W. V. Quine for criticizing an earlier draft.
References
1 I would like to thank Professor W. V. Quine for criticizing an earlier draft.
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