# Break after arrow

The length of formula in attached code is getting too long, I would wish to break it short. I try to insert a break after the \rightsquigarrow by failed.

How should I insert a break?

   \documentclass[conference]{IEEEtran}

\usepackage{amsmath, amssymb, url, proof}
\newcommand{\srule}[3]{
\infer[ (#1) ]
{#3}
{#2}
\bigskip
}
\begin{document}

{\centering
\begin{minipage}{1\textwidth}
\srule{if2}
{ \bigwedge\limits_{i=1}^n t_1 \leq t_i}
{(t_1\Rightarrow P_1,\ldots,t_n\Rightarrow P_n),C,D)
\stackrel{\tau}\rightsquigarrow
(P_1, C \land \bigwedge\limits_{i=1}^n t_1 \leq t_i,D+t_1))}
\end{minipage}

}

\end{document}


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 The equation is a little unusual, so it's difficult to make a suggestion. Could you add a picture illustrating the result that you want? – Ian Thompson Jul 28 '12 at 18:26 Hi, I have edited the question to put the picture of expected result. – william007 Jul 29 '12 at 1:48 I guess you don't want the "if" from if2 in math mode, do you? At the moment it looks like the variables i and f. – Hendrik Vogt Aug 5 '12 at 9:09

You could just add another \stackrel{} to achieve:

Alternatively, you could use \shortstack{}{} as discussed at \shortstack when writing text in nodes in TikZ and shown in the example below. This also produces an image as above.

## Code:

\documentclass[conference]{IEEEtran}

\usepackage{amsmath, amssymb, url, proof}
\newcommand{\srule}[3]{
\infer[ (#1) ]
{#3}
{#2}
\bigskip
}
\begin{document}

{\centering
\begin{minipage}{1\textwidth}% ---------- \stackrel version
\srule{if2}
{ \bigwedge\limits_{i=1}^n t_1 \leq t_i}
{\stackrel{\displaystyle(t_1\Rightarrow P_1,\ldots,t_n\Rightarrow P_n),C,D)
\stackrel{\tau}\rightsquigarrow}
{(P_1, C \land \bigwedge\limits_{i=1}^n t_1 \leq t_i,D+t_1))}}
\end{minipage}
%
\begin{minipage}{1\textwidth}% ---------- \shortstack version
\srule{if2}
{ \bigwedge\limits_{i=1}^n t_1 \leq t_i}
{\shortstack{$(t_1\Rightarrow P_1,\ldots,t_n\Rightarrow P_n),C,D) \stackrel{\tau}\rightsquigarrow$ \\
$(P_1, C \land \bigwedge\limits_{i=1}^n t_1 \leq t_i,D+t_1))$}}
\end{minipage}
}
\end{document}

-

Vertical stacking is easily obtained using array. The following MWE uses a \frac to stack elements as well as array for "sub-stacking" the lower part:

\documentclass[conference]{IEEEtran}

\usepackage{amsmath, amssymb, url, proof}
\newcommand{\srule}[3]{
\infer[ (#1) ]
{#3}
{#2}
\bigskip
}

\begin{document}

\centering
\begin{minipage}{1\textwidth}
\srule{if2}
{ \bigwedge\limits_{i=1}^n t_1 \leq t_i}
{(t_1\Rightarrow P_1,\ldots,t_n\Rightarrow P_n),C,D)
\stackrel{\tau}\rightsquigarrow
(P_1, C \land \bigwedge\limits_{i=1}^n t_1 \leq t_i,D+t_1))}
\end{minipage}

$\frac {\bigwedge\limits_{i=1}^n t_1 \leq t_i} {\begin{array}{@{}c@{}} ((t_1\Rightarrow P_1,\ldots,t_n\Rightarrow P_n),C,D) \stackrel{\tau}\rightsquigarrow \\ (P_1, C \land \bigwedge\limits_{i=1}^n t_1 \leq t_i,D+t_1) \end{array}}\ (if2)$

\end{document}

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