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

Question

\documentclass{article}
\usepackage{...} %packages your code nees

\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?

Answer 1

Your input

\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.

Instead of the clumsy

\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}
\usepackage{amsmath,amssymb} %packages your code nees

\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}