Talk:Non-Equivalence of Proposition and Negation/Formulation 1

This is not proof by contradiction. Proof by contradiction demonstrates the falsity of a statement by showing that it implies a contradiction. This sequent merely expresses the trivium that a statement that implies the negation of itself is itself a contradiction, and so if anything is an instance of Principle of Non-Contradiction. --prime mover (talk) 22:56, 3 May 2013 (UTC)


 * Please read it more carefully. That is not what it says at all. I never called it PBC, I called it a corollary of that. If you like a different name, go ahead and change it. --Dfeuer (talk) 23:04, 3 May 2013 (UTC)


 * The only other form I was going to put up was $\lnot (p \iff \lnot p)$, which I think gives a very clear picture of what this theorem is saying. --Dfeuer (talk) 23:06, 3 May 2013 (UTC)


 * What I'm saying is please don't put these results as corollaries of others. They don't belong there.


 * I understand what you're saying and it's not so special, it's just stuff which can be proved by application of proof rules.


 * Not special. Just useful. --Dfeuer (talk) 23:46, 3 May 2013 (UTC)