Alternative to \substack{} for a related purpose

Question

I would like to write something like the following, but involves mathematical symbols:

I tried using the \substack{} but it makes the font smaller. I'd like a novel alternative to achieve this.

And, thank you TeX.SX users for being helpful !

Edit: I have received wonderful answers here, as is true of many of my other questions. I have chosen the answer whose code I am using now. I sincerely wish I could upvote answers several times and accept several answers. :-(

Answer 1

For a somewhat simpler solution you could use something like

\begin{align*}
\begin{Bmatrix}
& \text{hi}  \\
& \text{hello}
\end{Bmatrix}
\longleftrightarrow
\begin{Bmatrix}
& \text{The droids} \\
& \text{lorrem lipsum}
\end{Bmatrix}
\end{align*}

to get the exact arrow style you would have to use tikz and the arrows libary.

Answer 2

Just use tabular for the text, or replace tabular with array for mathematics. You could also consider the Bmatrix environment from the amsmath package for the latter case.

\documentclass{article}
\begin{document}
\[
\left\{ 
\begin{tabular}{c}
TeX.SX users that \\
ask questions on \\
this site
\end{tabular}
\right\}
\longleftrightarrow
\left\{ 
\begin{tabular}{c}
TeX users in the \\
world using \\
TeX.SX
\end{tabular}
\right\}
\]
\end{document}

Answer 3

here are two possibilities, using amsmath. the spacing inside the braces is different, which may influence your preference.

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\[
 \left\{
  \begin{array}{c}
   a + b\\
   c + d\\
   e + f
  \end{array}
 \right\}
\quad\longleftrightarrow\quad
 \left\{
  \begin{array}{c}
   g + h\\
   i + j\\
   k + l
  \end{array}
 \right\}
\]

\[
 \begin{Bmatrix}
   a + b\\
   c + d\\
   e + f
 \end{Bmatrix}
\quad\longleftrightarrow\quad
 \begin{Bmatrix}
   g + h\\
   i + j\\
   k + l
 \end{Bmatrix}
\]
\end{document}

and the output: