I would like to be able to break lines in a math environment but in a way that keeps a symbol in front of the formula.

For example, the sum (sigma) followed by a long formula. So it goes out of the page but I would like to keep the formula next to the sigma even if there's a line break.

Here's a snippet so you can better reproduce it.

\documentclass{article}
\usepackage{amsmath,amsfonts,amssymb,mathtools}

% allows me to increase the font size of math blocks
\usepackage{graphicx} % \scalebox
\usepackage{environ}
\NewEnviron{mymath}{%
    \[
        \scalebox{1.3}{$\BODY$}
    \]
}

\begin{document}
    Lorem ipsum dolor sit amet
    \begin{mymath}
        \sum \limits _{\substack{
            yyyyyyy,\\
            zzzzzzzz,\\
            www
        }}
        (
            xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
        )   (
            xxxxxxxxxxxxxxxxxxxxxxxxxxxxx
        )
    \end{mymath}
\end{document}

And here's a screenshot of what I'm trying to achieve.

So as you can see, I'm trying to keep the second parenthesis next to the sigma but under the first parenthesis.

CodePudding user response：

First off: