This is LaTeX code:
[latex]
\begin{aligned} \sum_{i\in\omega^2} (i+\omega) & = \sup_{\omega\cdot k+l\in\omega^2} \big(\omega^2\cdot k+\omega\cdot(k+1)\cdot l\big) \\ & = \omega^3 \end{aligned}
[/latex]