# Force iteration range to be under a symbol

Given:

$$out = \displaystyle \oplus_{i = 1 ... l} r_i$$


How can I force \oplus to place i = 1 ... l to be strictly under the oplus symbol?

Thank you

\documentclass{article}
\usepackage{mathtools}
\begin{document}

$$\text{out} = \mathop{\oplus}\limits_{i = 1 \ldots l} r_i$$

$$\text{out} = \mathop{\oplus}\limits_{\mathclap{i = 1 \ldots l}} r_i$$
\end{document}


\documentclass{article}

\begin{document}

$$\mathrm{out} = \bigoplus_{i = 1 \ldots l} r_i$$
\end{document}


\oplus is designed as an infix binary operator, \bigoplus is designed as a prefix operator (the same distinction as + and \sum)

Note in your original \displaystyle is not needed as that is the default in equation, also multiletter identifiers such as out should be set as \mathrm (or \mathit if you want italic)