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I just started learning set theory.I have a question I need to answer for revision. I missed a bit of my lecture so i'm a little lost and I have yet to receive my textbook.

The question is: "Write [–3..1] as a set by explicitly listing all its elements. "

Just wondering how that works?

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    @Ben: Yes, which is what leads me to believe it's some sort of "local" notation; sorry I didn't make that clear in my comment (note I used the OPs notation in the last part).2011-08-18

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If $n$ and $m$ are integers with $n\le m$, the two-dots notation $[n..m]$ commonly denotes the set of integers between $n$ and $m$ inclusive: $[n..m] = \{k \in \mathbb{Z}:n \le k \le m\}$. If that’s the convention that your class is using $-$ and it’s common in computer science, so it’s not unusual in discrete math courses $-$ then $[-3..1] = \{-3,-2,-1,0,1\}$.