ranges: Xy= -y to y ; in other words X will be equal to the range from -y to y which X is integer

Ryan$

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Jan 25, 2019
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Hi guys, I'm a lil confused about this formula which is saying like this :
Xy= -y to y ; in other words X will be equal to the range from -y to y which X is integer, for instance X1= -1 0 1 , X2=-2 -1 0 1 2

what's confusing me if X0 , what's the range ? is it 0? if so then why? I tried to do like this X0=-0 to 0 , but what does that mean?
 

Dr.Peterson

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Nov 12, 2017
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I'm not familiar with that notation; please show us a source for it, so we can be sure we are understanding you correctly. The way you said this is not what a mathematician would say, which would be very carefully defined.

It looks like you are saying that someone has defined a set \(\displaystyle X_a\) as the set \(\displaystyle \{x \in Z | -a \le x \le a\}\). If so, then \(\displaystyle X_0\) would be {0}, since 0 is the only integer that is between -0 and 0, inclusive.
 

Ryan$

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Jan 25, 2019
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I think it means -a<=x<=a , thanks alot!
 

Otis

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