If and only if

hihihi9993

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 ⇔/???

akistotle

@d931n027h 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/

hihihi9993

@akistotle Got it!!!! Thank you always

fmihalic2

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