# Problem in writing the equation: missing delimiter (.inserted)

\documentclass{article}

\begin{document}

\begin{align}
T\triangleq &\int_{0}^{\infty}\frac{\gamma^{k+m_2-1}{\rm exp}\Big(-\frac{m_2\gamma}{\bar\gamma_2}\Big)}{\Big1+(\frac{(m_1+s\bar\gamma_1)\gamma}{cm_1}\Big)^{m_1}(1+\frac{1}{c}\gamma_2)^{\lceil m_1 \rceil -m_1}}{\rm d}\gamma.\\
\nonumber
=&C\int_{0}^{\infty}\gamma^{k+m_2-1}{\rm exp}\Bigg(-\frac{m_2\gamma}{\bar\gamma_2}\Bigg)\\
&\texttimes H_{1,1}^{1,1} \left[\begin{gathered} \frac{(m_1+s\bar\gamma_1)\gamma}{cm_1}\end{gathered}\left\vert \begin{gathered} (1-m_1,1) \\ (0,1)\end{gathered}\right.\right]H_{1,1}^{1,1} \left[\begin{gathered} \frac{\gamma}{c}\end{gathered}\left\vert \begin{gathered} (1-\lceil m_1 \rceil +m_1,1) \\ (0,1)\end{gathered}\right.\right]{\rm d}\gamma\\
=&C\Bigg(\frac{\bar\gamma_2}{m_2}\Bigg)^{k+m_2}H_{1,\,[1:\,1],\,0,\,[1:\,1]}^{1,\,1,\,1,\,1,\,1} \left[\begin{gathered}
\frac{(m_1+s\bar{\gamma}_{_1})\bar{\gamma}_{_2}}{c\,m_1m_2} \\ \frac{\bar{\gamma}_{_2}}{c\,m_2}\end{gathered}
\left\vert \begin{gathered} (k+m_2,1) \\ (1-m_1,1);(1-\lceil{m_1}\rceil+m_1,) \\ - \\ (0,1);(0,1)
\end{gathered}\right.\right].\\
=&C\Bigg(\frac{\bar\gamma_2}{m_2}\Bigg)^{k+m_2}G_{1,\,[1:\,1],\,0,\,[1:\,1]}^{1,\,1,\,1,\,1,\,1}\left[\begin{gathered}\frac{(m_1+s\bar{\gamma}_{_1})\bar{\gamma}_{_2}}{c\,m_1m_2}\\\frac{\bar{\gamma}_{_2}}{c\,m_2}\end{gathered}\left\vert \begin{gathered} k+m_2\\1-m_1;1-\lceil{m_1}\rceil+m_1 \\ - \\ 0;0\end{gathered}\right.\right].
\end{align}

\end{document}


I have successfully generated the equation in the picture, but after compiling LaTeX always showed that Missing delimiter (.inserted). \end{align} What's the solution?

• a ![enter image description here][1] crept into the last line and perhaps you could add a preamble and postamble so your example is a complete document? – hkBst Jul 10 '15 at 14:27
• \Big1 is wrong; you probably meant 1+\Big(; however it should be \Bigl( and \Bigr) throughout. Also {\rm exp} is wrong and it should be \exp, and {\rm d} should be \mathrm{d}. – egreg Jul 10 '15 at 14:45
• Also, you should use &= not =&. – Sigur Jul 10 '15 at 14:50

\Big1+(


should be

1+\Bigl(


Also the other \Big tokens should be changed: use \Bigl in front of an opening delimiter and \Bigr in front of a closing delimiter. Similarly for \Bigg, which should be either \Biggl or \Biggr.

Use \exp, not {\rm exp} and \,\mathrm{d} in place of {\rm d}. The \rm command has been deprecated for 20 years.

If you want the alignment point after the = (or \triangleeq), then use ={}& or the spacing will be wrong.

The command \texttimes is wrong, it should be \times.

\left[ <...> \left| <...> \right.\right]


construct, you can use

\left[ <...> \;\middle|\; <...> \right]


Final point to note: you have several \gamma_{_1} or similar, which are wrong: if you want to lower the subscript, type

\gamma^{}_{1}


Here's a fixed version

\documentclass{article}

\begin{document}

\begin{align}
T\triangleq{} &
\int_{0}^{\infty}
\frac
{\gamma^{k+m_2-1}\exp\Bigl(-\frac{m_2\gamma}{\bar\gamma_2}\Bigr)}
{1+\Bigl(\frac{(m_1+s\bar\gamma_1)\gamma}{cm_1}\Bigr)^{m_1}(1+\frac{1}{c}\gamma_2)
^{\lceil m_1 \rceil -m_1}}
\,\mathrm{d}\gamma
\\
\nonumber
={}& C\int_{0}^{\infty}\gamma^{k+m_2-1}\exp\Biggl(-\frac{m_2\gamma}{\bar\gamma_2}\Biggr)
\\
&\times H_{1,1}^{1,1}
\left[
\frac{(m_1+s\bar\gamma_1)\gamma}{cm_1}
\;\middle|\;
\begin{gathered} (1-m_1,1) \\ (0,1)\end{gathered}
\right]
H_{1,1}^{1,1}
\left[
\frac{\gamma}{c}
\;\middle|\;
t \begin{gathered} (1-\lceil m_1 \rceil +m_1,1) \\ (0,1)\end{gathered}
\right]
\mathrm{d}\gamma
\\
={}& C\Biggl(\frac{\bar\gamma_2}{m_2}\Biggr)^{k+m_2}
H_{1,\,[1:\,1],\,0,\,[1:\,1]}^{1,\,1,\,1,\,1,\,1}
\left[
\begin{gathered}
\frac{(m_1+s\bar{\gamma}^{}_{1})\bar{\gamma}^{}_{2}}{c\,m_1m_2} \\
\frac{\bar{\gamma}^{}_{2}}{c\,m_2}
\end{gathered}
\;\middle|\;
\begin{gathered}
(k+m_2,1) \\
(1-m_1,1);(1-\lceil{m_1}\rceil+m_1,) \\
- \\
(0,1);(0,1)
\end{gathered}
\right]
\\
={}& C\Biggl(\frac{\bar\gamma_2}{m_2}\Biggr)^{k+m_2}
G_{1,\,[1:\,1],\,0,\,[1:\,1]}^{1,\,1,\,1,\,1,\,1}
\left[
\begin{gathered}
\frac{(m_1+s\bar{\gamma}^{}_{1})\bar{\gamma}^{}_{2}}{c\,m_1m_2}\\
\frac{\bar{\gamma}_{_2}}{c\,m_2}
\end{gathered}
\;\middle|\;
\begin{gathered}
k+m_2\\1-m_1;1-\lceil{m_1}\rceil+m_1 \\
- \\
0;0\end{gathered}
\right].
\end{align}

\end{document}


• @Sigur I'll fix it immediately. – egreg Jul 10 '15 at 15:21
• The reason to use ={}& instead of the classical &= is due to \times? – Sigur Jul 10 '15 at 15:23
• Thank you soooooo much for the detailed solution! I am still a green hand on this and also try hard to read The LaTeX Companion these days, so I don't understand lots of the grammar and expression clearly yet. And yet I got another problem: If I want to generate this equation using \begin{eqnarray} and \end{eqnarry}, what's the difference? And which method is more acceptable? – Vinnton Yao Jul 11 '15 at 14:55
• And indeed I am using \IEEEtran so that the article has two columns. But the equation above is so long and large that I have to use \onecolumn to make it display in the middle of the paper, however I was told that the format doesn't fit the requirements. So my question is how can I put the long equation above in just the half of the paper? – Vinnton Yao Jul 11 '15 at 15:26
• @VinntonYao Sorry, you can't. Use shorthands. – egreg Jul 11 '15 at 19:33