User:TestUser/sandbox

Test of \label, eqref:

$$\max\{A,B\} = \begin{cases} A & \mathrm{ if\ } A\ge B\\ B & \mathrm{ otherwise } \end{cases}.\label{xxx}$$

As said in \eqref{xxx}, $\max\{A,B\}$ is $A$ unless $A < B$.