So I'm trying to figure out how to correctly display a natural number that lies in an interval and when searching for it, I get a variety of ways and so I'm unsure about the correct one

So say we have something like all even natural numbers between 0 and 10.

The way I did it: {${2x | x \in N∧ 0 \leq x \leq 5}$}

But then, others write it as {${2x | x \in N}, 0 \leq x \leq 5$} or some even use the "therefore |" sign in different ways or skip the "therefore" at the beginning all together and add it after the set definition so its all a bit much.

I'm really unsure about how to define sets properly, would really appreciate some (beginner friendly) help. Thanks in advance!


There are a lot of potential ways to represent this set, all of which are valid. In the two examples you have listed, the only difference is the way that the two properties are separated. You could also just use a word to separate them like $\{2x|x\in N and\, 0\leq x\leq5\}$. When I define sets, I like to use a colon : instead of the vertical line | so it looks like $\{2x:x\in N and\, 0\leq x\leq5\}$. I like the way this looks better, especially when written by hand where the | can look like a 1. You could also write it as $\{x|x$ is even and $0\leq x\leq10\}$.

If you have a teacher that has a specific way in mind to define sets, try to look at examples they have and follow that way. If not, there are lots of ways to define the same set.

  • $\begingroup$ Thanks, that's helpful. $\endgroup$ – user472288 Oct 27 '19 at 4:14

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.