Talk:Method of Truth Tables/Proof of Tautology

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Most of this would actually be more appropriate on Definition:Truth Table (viz the explanation of how to fill a row) because it applies in a broader context, before the consistency and completeness theorems are dealt with. --Lord_Farin (talk) 10:57, 19 February 2013 (UTC)

Agreed (tentatively) - I'm not happy with how this area is structured, so feel free to offer up something better.
Most of this was originally inspired (pre-ProofWiki) by the treatment in 1980: D.J. O'Connor and Betty Powell: Elementary Logic which goes into considerable detail as to how to use a truth table, far more than is necessary for practical mathematical logic (the book itself is geared towards non-mathematicians, emphasising the translation of natural language into symbology and makes an incredibly big meal of the technical aspects which most other books take for granted). That said, the book has some useful explanations of many of the concepts which more technical texts gloss over, so is still worth including in our list of source works. --prime mover (talk) 11:27, 19 February 2013 (UTC)


The statement "true in all models" should be modified, I think. This only proves the case for simple $\{0,1\}$ models, no? It is apparently possible to show that this demonstrates it for all models whose truth values form a boolean algebra, but this is not immediate. And it certainly does nothing for models of non-standard logic.... --Dfeuer (talk) 18:44, 31 May 2013 (UTC)

In context it's adequate. --prime mover (talk) 20:57, 31 May 2013 (UTC)