I have the following formula:

$$ \Omega \subset \mathbb{R}^d, $$

where $d=2$ or $d=3$. But I find this style of notation quite cumbersome. Is there any way, how to note, that $d$ equals to 2 or 3 exclusively and in more elegant way?

  • 1
    $\begingroup$ $d\in\{2,3\}$. That's all I can think of. $\endgroup$
    – drhab
    Apr 13, 2017 at 10:11
  • 2
    $\begingroup$ @eenoku Personally, I'd prefer seeing the one you mentioned. $\endgroup$
    – user228113
    Apr 13, 2017 at 10:12

1 Answer 1


You could write $\Omega\subset\mathbb{R}^2\lor \Omega\subset\mathbb{R}^3$, or $\Omega\in\mathcal{P}\left(\mathbb{R}^2\right)\bigcup\mathcal{P}\left(\mathbb{R}^3\right)$. Here $\mathcal{P}\left(S\right)$ denotes the power set of $S$, i.e. its set of subsets. (Note $S\in\mathcal{P}\left(S\right)$. If your use of $\subset$ was meant to imply proper subsets, that second option should be amended to $\Omega\in\mathcal{P}\left(\mathbb{R}^2\right)\bigcup\mathcal{P}\left(\mathbb{R}^3\right)\backslash\left\{\mathbb{R}^2,\,\mathbb{R}^3\right\}$.)


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.