Subject: Re: [HM] Truth tables
From: Martin Davis (martin@eipye.com)
Date: Thu Apr 20 2000 - 12:41:00 EDT
I should point out that Post used truth tables to prove the completeness
of the axioms for the propositional calculus of Whitehead and Russell's
PRINCIPIA MATHEMATICA. As with Paul Bernays's slightly earlier proof of
this result (a proof that was first published in the Hilbert-Ackermann
textbook in 1928), Post used expansion into disjunctive normal form. But
Bernays did not explicitly use truth tables in his proof.
Post's method lent itself to generalization: truth tables with an arbitrary
finite number of truth values instead of just 2; and these also appear in
his dissertation.
Martin Davis
Martin Davis
Visiting Scholar UC Berkeley
Professor Emeritus, NYU
martin@eipye.com
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http://www.eipye.com
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