Talk:Contraposition

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I have archived the previous discussions simply because they were all 4 years old or older. But I want to discuss something that was already brought up in those, namely mergers, since Wikipedia has many pages on the same topics. I want to start by merging Proof by contrapositive here, since it is a short article on a topic that relates very closely to this one. What do people think? Thiagovscoelho (talk) 11:47, 20 April 2024 (UTC)Reply

Update: This merger has been performed. Thiagovscoelho (talk) 11:17, 30 April 2024 (UTC)Reply

I think it would also be good to merge Contraposition (traditional logic) here. The pages are closely connected. If this page covers contraposition in nonclassical logics, it should cover contraposition in traditional logic too. The material in the other page is very short and could be a section here. Thiagovscoelho (talk) 11:33, 30 April 2024 (UTC)Reply

Update: This merger has been performed. Thiagovscoelho (talk) 00:29, 16 May 2024 (UTC)Reply

I found that at Contraposition#Examples, it is claimed that :

• "Since the statement and the converse are both true, it is called a biconditional", and further below it is also claimed that,
• "If a statement (or its contrapositive) and the inverse (or the converse) are both true or both false, then it is known as a logical biconditional.".

I agree with the first claim. Then my interpretation of the second phrase is "If a statement and the inverse are both true or false then it is know as a logical biconditional", which is wrong because the definition of equivalence is "A -> B (the original statement) and B -> A (the converse)".

I don't see why the thruth values are being specified. May be my interpretation is wrong ? Oversleep9 (talk) 12:36, 13 August 2025 (UTC)Reply