# How to rotate symbols in the equation environment?

I would like to make the following equation in the equation environment

However, I don't know how to insert the equality symbol that links both lines. Can this be done in the equation environment? If not, should we proceed?

• A similar question with accepted answers is available on this post. Nov 15 '19 at 23:54
• Unless this is a common notation, you might also look at \underbrace and \overbrace from the mathtools package. Nov 16 '19 at 15:05

Most likely some very similar answer exists somewhere but I was not able to find it.

\documentclass{article}
\usepackage{mathtools}
\usepackage{graphicx}
\usepackage{eqparbox}
\begin{document}
\begin{align*}
\eqmakebox[pft]{$\widetilde{h\circ\partial+\partial\circ h}$}&=
\widetilde{h\circ\partial}+\widetilde{\partial\circ h}=
\widetilde{h}\circ\widetilde{\partial}+\widetilde{\partial}\circ\widetilde{h}\\
\eqmakebox[pft][c]{\rotatebox[origin=c]{90}{$=$}}&\\
\widetilde{(\bar\ell_1)_{\#}+(\bar\ell_1)_{\#}}&=
\widetilde{(\bar\ell_1)_{\#}}+\widetilde{(\bar\ell_1)_{\#}}
=(\bar\ell_1)^{\#}+(\bar\ell_1)^{\#}
\end{align*}
\end{document}

Or with the really wide tilde from this answer.

\documentclass{article}
\usepackage{mathtools}
\usepackage{scalerel}
\usepackage{stackengine,wasysym}

\newcommand\reallywidetilde[1]{\ThisStyle{%
\setbox0=\hbox{$\SavedStyle#1$}%
\stackengine{-.1\LMpt}{$\SavedStyle#1$}{%
\stretchto{\scaleto{\SavedStyle\mkern.2mu\AC}{.5150\wd0}}{.6\ht0}%
}{O}{c}{F}{T}{S}%
}}
\usepackage{eqparbox}
\begin{document}
\begin{align*}
\eqmakebox[pft]{$\reallywidetilde{h\circ\partial+\partial\circ h}$}&=
\reallywidetilde{h\circ\partial}+\reallywidetilde{\partial\circ h}=
\widetilde{h}\circ\widetilde{\partial}+\widetilde{\partial}\circ\widetilde{h}\\
\eqmakebox[pft][c]{\rotatebox[origin=c]{90}{$=$}}&\\
\reallywidetilde{(\bar\ell_1)_{\#}+(\bar\ell_1)_{\#}}&=
\reallywidetilde{(\bar\ell_1)_{\#}}+\reallywidetilde{(\bar\ell_1)_{\#}}
=(\bar\ell_1)^{\#}+(\bar\ell_1)^{\#}
\end{align*}
\end{document}

For the future I would kindly like to ask you to show what you have tried such that others do not have to punch in the formulae from a screen shot.

Here's a way with eqparbox and yhmath (for \widetilde):

\documentclass{article}
\usepackage{mathtools}
\usepackage{yhmath}
\usepackage{eqparbox, graphicx}

\newcommand*{\eqmathbox}[2][M]{\eqmakebox[#1]{$\displaystyle#2$}}

\begin{document}

\begin{align*}
\eqmathbox{ \widetilde{h\circ \partial + \partial\circ h}} & = \widetilde{h\circ \partial} +\widetilde{ \partial\circ h} =\bar{\partial}\circ \widetilde{h}+ \widetilde{h}\circ\bar{\partial} \\[-1ex]
\eqmathbox{\rotatebox[origin=c]{90}{$=$}} \\[-0.5ex]
\eqmathbox{\widetilde{(u_{1})_{\sharp}-(u_{0})_{\sharp}}} & = \widetilde{(u_{1})}_{\sharp}- \widetilde{(u_{0})}_{\sharp} = (i_{1})^{\sharp}- (i_{0})^{\sharp}
\end{align*}

\end{document}