# Cannot split equation

I do not seem to be able to split this very long equation. I've tried multline, align, dmath, split and a few other possibilities but none of them have worked; it might be a stupid mistake, but I can't find it. (New to LaTeX)

$$W = \int_{k<\Lambda} [Dg][DA][D\psi][D\Phi] \exp{\Biggl\{ i \int d^{4}x \sqrt{-g} \Biggl[\frac{m_{p}^{2}}{2}R - \frac{1}{4}F_{\mu\nu}^{a}F^{a\mu\nu} + i\bar{\psi}^i\gamma^{\mu}D_{\mu}\psi^i + \Bigl(\bar{\psi}_{L}^{i} V_{ij} \Phi \psi_{R}^{j} + h.c. \Bigr) - |D_{\mu}\Phi|^2 - V(\Phi)\Biggr] \Biggr\}}$$

• Hint: If you make your snippets compilable, the helpers can act faster. :-) – Johannes_B Jan 2 '16 at 20:28

As far as understand question, you looking for something like this:

\documentclass{article}
\usepackage{amsmath}

\begin{document}
\begin{multline}
W = \int_{k<\Lambda} [Dg][DA][D\psi][D\Phi] \exp\biggl\{ i \int d^{4}x \sqrt{-g} \biggl[\frac{m_{p}^{2}}{2}R- \frac{1}{4}F_{\mu\nu}^{a}F^{a\mu\nu}\\
%
\qquad + i\bar{\psi}^i\gamma^{\mu}D_{\mu}\psi^i + \bigl(\bar{\psi}_{L}^{i} V_{ij} \Phi \psi_{R}^{j} + h.c. \bigr) - |D_{\mu}\Phi|^2 - V(\Phi)\biggr] \biggr\}
\end{multline}
\end{document}


Reason, why you receive errors in your effort to split equations, is use \left ... \right parenthesis, as explained @Przemysław Scherwentke in his answer.

Edit: As suggested @egreg, with \bigg size of parenthesis the equation looks nicer.

Edit (2): To vertical centering of equation number can be obtain width mathtolls package environment multilined:

\documentclass{article}
\usepackage{mathtools}

\begin{document}
$$\begin{multlined} W = \int_{k<\Lambda} [Dg][DA][D\psi][D\Phi] \exp\biggl\{i \int d^{4}x \sqrt{-g} \biggl[\frac{m_{p}^{2}}{2}R- \frac{1}{4}F_{\mu\nu}^{a}F^{a\mu\nu} \\ % \qquad + i\bar{\psi}^i\gamma^{\mu}D_{\mu}\psi^i + \bigl(\bar{\psi}_{L}^{i} V_{ij} \Phi \psi_{R}^{j} + h.c. \Bigr) - |D_{\mu}\Phi|^2 - V(\Phi)\biggr] \biggr\} \end{multlined}$$
\end{document}


which gives:

• I'd suggest \bigg size – egreg Jan 2 '16 at 20:46

This is an example of splitting. The source of mistake in tries of align etc. was { after \exp.

\documentclass{article}
\usepackage{amsmath}
\usepackage{latexsym}
\begin{document}

%$$%W = \int_{k<\Lambda} [Dg][DA][D\psi][D\Phi] \exp{\Biggl\{ i \int d^{4}x \sqrt{-g} \Biggl[\frac{m_{p}^{2}}{2}R - \frac{1}{4}F_{\mu\nu}^{a}F^{a\mu\nu} + i\bar{\psi}^i\gamma^{\mu}D_{\mu}\psi^i + \Bigl(\bar{\psi}_{L}^{i} V_{ij} \Phi \psi_{R}^{j} + h.c. \Bigr) - |D_{\mu}\Phi|^2 - V(\Phi)\Biggr] \Biggr\}} %$$
\begin{align}
W &= \int_{k<\Lambda} [Dg][DA][D\psi][D\Phi] \exp\Biggl\{ i \int d^{4}x \sqrt{-g} \Biggl[\frac{m_{p}^{2}}{2}R- \frac{1}{4}F_{\mu\nu}^{a}F^{a\mu\nu}\notag\\
&\qquad + i\bar{\psi}^i\gamma^{\mu}D_{\mu}\psi^i + \Bigl(\bar{\psi}_{L}^{i} V_{ij} \Phi \psi_{R}^{j} + h.c. \Bigr) - |D_{\mu}\Phi|^2 - V(\Phi)\Biggr] \Biggr\}
\end{align}

\begin{align}
W &= \int_{k<\Lambda} [Dg][DA][D\psi][D\Phi] \exp\biggl\{ i \int d^{4}x \sqrt{-g} \biggl[\frac{m_{p}^{2}}{2}R- \frac{1}{4}F_{\mu\nu}^{a}F^{a\mu\nu}\notag\\
&\qquad + i\bar{\psi}^i\gamma^{\mu}D_{\mu}\psi^i + \Bigl(\bar{\psi}_{L}^{i} V_{ij} \Phi \psi_{R}^{j} + \mathrm{h.c.} \Bigr) - |D_{\mu}\Phi|^2 - V(\Phi)\biggr] \biggr\}
\end{align}

\end{document}


I would recommend the second version, with \biggl and \mathrm{h.c.}.

• One doesn't really want each line to be numbered here though, would one? – Torbjørn T. Jan 2 '16 at 20:56
• @TorbjørnT. Oh, yes. Adding \notag. – Przemysław Scherwentke Jan 2 '16 at 21:01

Here's a solution that uses a split environment inside an equation environment.

I would also like to suggest that you use \int\limits instead of "just" \int for the first integral symbol. That way, the limit of integration is set below the integral symbol, making the whole expression more compact. For increased legibility/parsability, one could add a thin-space, \,, after \sqrt{-g} and before the large opening square bracket. See the code below for an implementation of these ideas.

Finally, do note that \exp is a math operator and does not take an argument.

\documentclass{article}
\usepackage{amsmath} % for "split" environment
\begin{document}

$$\begin{split} W &= \int\limits_{k<\Lambda} [Dg][DA][D\psi][D\Phi] \exp\biggl\{ i \int d^{4}x \sqrt{-g} \,\biggl[\frac{m_{p}^{2}}{2}R - \frac{1}{4}F_{\mu\nu}^{a}F^{a\mu\nu} \\ &\qquad + i\bar{\psi}^i\gamma^{\mu}D_{\mu}\psi^i + \Bigl(\bar{\psi}_{L}^{i} V_{ij} \Phi \psi_{R}^{j} + h.c. \Bigr) - |D_{\mu}\Phi|^2 - V(\Phi)\biggr] \biggr\} \end{split}$$
\end{document}
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