# How to write following equation

I am trying to write the following equation for my paper. I am familiar with using big braces, but I am not sure how to write multiple lines within the braces as in the image attached. The following gives me the left side and the huge braces:

$t\rightarrow_{A}t' \iff \Bigg\{ \exists C$

• You can insert array after the brace. Or aligned if you want to align something. Feb 12, 2019 at 14:05
• As an alternative, cases is also ok (although it is not really for this purpose).
– user156344
Feb 12, 2019 at 14:17
• with help of mathtool: $t \xrightarrow{\mathcal{A}} t' \Leftrightarrow \left\{\begin{array}{l} xxx\\ yyy'\\ ...\end{array}\right.$. i can provide an answer if you will extend provide a mwe with your equation. Feb 12, 2019 at 14:18
• @JouleV Please provide a complete answer, I do not get you Feb 12, 2019 at 15:53
• @Zarko I have provided a MWE in my question Feb 12, 2019 at 15:53

Summarising everything (had some free-time) ;-).

\documentclass[10pt,a4paper]{article}
\usepackage{amsmath}
\begin{document}
$t\xrightarrow[\mathcal{A}]{} t'\Leftrightarrow\begin{cases} \exists C\in\mathcal{C}(\mathcal{F}\cup Q),\exists u_1,\ldots,u_n\in T(\mathcal{F}),\\ \exists f(q_1(x_1),\ldots,q_n(x_n))\rightarrow q(f(x_1,\ldots,x_n))\in\Delta,\\ t=C[f(q_1(u_1),\ldots,q_n(u_n))],\\ t'=C[q(f(u_1,\ldots,u_n))]. \end{cases}$
\end{document}


you will get:

• should stick that in display math
– JPi
Feb 12, 2019 at 15:14
• @JPi I decided to let the OP do that ;) Feb 12, 2019 at 16:06
• @Raaja This works for me. Feb 13, 2019 at 5:29

Summarizing the above comments, you can try

\documentclass[12pt]{article}
\usepackage{amsmath}
\begin{document}
\begin{equation*}
a \iff b \iff
\begin{cases}
c = d\\
e = f
\end{cases}
\end{equation*}
\end{document}