# An array inside breqn (dmath) breaks the line unnecessarily

Please check the following minimally working example. I know dmath is not needed in this case, but I need it in my original file.

\documentclass[12pt,letterpaper]{letter}
\usepackage{array,delarray,breqn}
\begin{document}
\begin{dmath}
y = x \begin{array}[c] ( {c} ) 2 x y \\ y^2- x^2 \end{array}
\end{dmath}
\end{document}


See how the y is alone on the line after which the line breaks to the rest of the equation? The line is still pretty empty, so why does the line break? Can I get rid of it?

• Welcome to TeX.SE. This site is not designed to be a place to report bugs. Have you contacted the maintainers of the breqn package? (Their email addresses are stated on the title page of the user guide of the breqn package.)
– Mico
Jul 16 '21 at 5:33
• Note that breqn has a lot of issues and is generally not recommended Jul 16 '21 at 6:16

It's not related to delarray it occurs (a bit more surprisingly) with pmatrix as well, but in either case you can hide the matrix with {..} I'd use pmatrix here.

\documentclass[12pt,letterpaper]{letter}
\usepackage{array,delarray,breqn}
\begin{document}
delarray
\begin{dmath}
y = x {\begin{array}[c] ( {c} ) 2 x y \\ y^2- x^2 \end{array}}
\end{dmath}

pmatrix
\begin{dmath}
y = x {\begin{pmatrix}y \\ y^2- x^2 \end{pmatrix}}
\end{dmath}
\end{document}