Hi all!

While I was studying, I encountered "(-/-)" sign, and started to wonder if it is interchangeable with "⇔/" .

Since "⇔/" is a negation of "if and only if", can we also use "(-/-)" for its negation?

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For example, Alan goes to the park everyday, except the days on which Chris goes to the park: /A⇔C = A(-/-)C ????????

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If we have A⇔/B = /A⇔B, then

A,/B (O)

/A,B (O)

A,B (X)

/A,/B (X)

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If we have A(-/-)B, then

A,/B (O)

/A,B (O)

A,B (X)

/A,/B (?! I assume X?)

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What's the definition of A(-/-)B? Either A or B is in, but not both? I mean it has to be an exclusive or in order to satisfy the reasoning...

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Someone please help! Thank you!

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Quick summary: (-/-) same as ⇔/???

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3 comments

  • Wednesday, Jun 21 2017

    They hate each other. If I see Alan, no Chris. If I see Chris, Alan stayed home to watch Netflix.

    1
  • Wednesday, Jun 21 2017

    @akikookmt881 Got it!!!! Thank you always (3(/p)

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  • Wednesday, Jun 21 2017

    @donamhyun690 said:

    While I was studying, I encountered "(-/-)" sign, and started to wonder if it is interchangeable with "⇔/" .

    I don't think 7Sage uses this sign, but by "(-/-)," do you mean "The Double-Not arrow" used by PowerScore?

    I believe they simply use it to indicate "Not both rule".

    A --> /B

    They say that "A (--|--) B" only excludes the situation that "A and B both occurs."

    They use "A (--|--) B" for "No As are Bs" and I think it is really confusing. I think we should stick to "Not both rule" (A --> /B).

    Be careful not to confuse "A --> /B" with "A (--) /B". They are not the same.

    A (--) /B (Or, but not both)

    https://classic.7sage.com/lesson/or-but-not-both/

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