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If we show that a claim is equivalent to a tautology (which is stronger than showing the claim implies a tautology), how come that isn't a valid method of proof?

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    Showing that the claim implies a tautology doesn't tell you anything, since a tautology should be true anyhow. It *is* sufficient to show that your claim follows from a tautology, so if you show that your claim is equivalent to a tautology, you have shown that it is true.2012-11-04
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    What text or class did this come from?2012-11-04

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