4
$\begingroup$

This is the expression: $$G=\bigsqcup_{d\mid n}X_d$$ I saw it here - Finite group for which $|\{x:x^m=e\}|\leq m$ for all $m$ is cyclic.

Thank you!

$\endgroup$
3
  • $\begingroup$ It usually means "disjoint union". $\endgroup$
    – user1729
    Dec 19, 2013 at 15:48
  • $\begingroup$ e.g. $\left\{1,2,3\right\}\cup\left\{4,5,6\right\}$? $\endgroup$
    – CS1
    Dec 19, 2013 at 15:49
  • 1
    $\begingroup$ Well, in curly brackets, but yes. $\{1, 2, 3\}\bigsqcup\{4, 5, 6\}$ but not $\{1, 2, 3\}\bigsqcup\{3, 4, 5, 6\}$. $\endgroup$
    – user1729
    Dec 19, 2013 at 15:50

2 Answers 2

6
$\begingroup$

Usually it means disjoint (pairwise). Others write $\biguplus$.

$\endgroup$
4
$\begingroup$

It means that the sets $X_d$ in the union are pairwise disjoint.

$\endgroup$

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .