Posting Freak
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Didn't really wanna make a thread for this but my other logic post was necro.
how do I deny (p<=>q)?
I'm thinking something like morgan but not sure:
(~p _v_ ~q) where _v_ is exclusive 'or' so it's one true but not both for it to work.
Posting Freak
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Make one true and one false.
True cannot imply false.
EAT THAT 21
Posting Freak
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Exactly it's a double implication. So if p is true and q is false then the whole thing is false.
Unless you're asking a different question.
Posting Freak
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Taking "not p and q or p and not q" would falsify the statement... aka "p xor q"
English equivalent of <=> is iff / if and only if / xnor
(I think I don't know the proper notation...)
Posting Freak
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Just to add-on, if you are talking about the double arrow in mathematics
<==>
Like someone said, it means "if and only if"
In order to prove it, you have to prove it in one direction, and then prove it in the other
i.e. Prove that p --> q, and q --> p
If you want to deny it, you only have to disprove one of them i.e. Make a contradiction happen in either direction