Missing equation numbers in aligned environment inside tabular environment

Question

I try to create a tabular environment containing a two-lined description on the left side of an equation on the right side. It looks like this:

\documentclass{report}

\usepackage[intlimits]{amsmath} 
\usepackage{here}           
\usepackage{floatflt}
\usepackage{caption}
\usepackage{listliketab}
\usepackage{tabularx}
\usepackage{booktabs}

\begin{document}
\begin{table}[htb]
\caption{testststt} \label{tab_BG1_zustand}
  \begin{tabular}{p{6cm}p{6cm}}
        \toprule
        Zustandsgröße &  Beziehung \\ \midrule 
       {$\!\begin{aligned} 
           &\text{spezifisches Volumen} \\ 
           & $v = (\partial g / \partial p)_T} \end{aligned}$}
           & $v(\pi,\tau)\frac{p}{R T} = \pie \gamma_{\pi}$ \\ \vspace{5mm} \\
        {$\!\begin{aligned}
            &\text{spezifische innere Energie} \\
            & $u=g-T(\partial g / \partial T)_p - p(\partial g / \partial p)_T \end{aligned}$}
            & $\frac{u(\pi,\tau )}{R T} = \tau \gamma_{\tau}$ \\ \bottomrule
  \end{tabular}
\end{table}
\end{document}

Since it's in an aligned environment, I thought that I would get equation numbers on the right. However, there are none. I think it's because aligned is a non-math environment, so I don't get equation numbers for the inline math; but if I exchange it with align I can't really get it to work.

Update I edited the code according to Bernard's answer, but with the intent to number the right equation:

\begin{table}[htb]
\caption{testststt} \label{tab_BG1_zustand}
\begin{tabular}{p{6cm}p{6cm}}
        \toprule
        Zustandsgröße &  Beziehung \\ \midrule 
        {$\!\begin{aligned} 
           &\text{spezifisches Volumen} \\ 
           &$v = (\partial g / \partial p)_T} \end{aligned}$}
   & \begin{equation}v(\pi,\tau)\frac{p}{R T} = \pie \gamma_{\pi}  \end{equation} \\ \vspace{5mm} \\
        {$\!\begin{aligned}
            &\text{spezifische innere Energie} \\
            &$u=g-T(\partial g / \partial T)_p - p(\partial g / \partial p)_T \end{aligned}$}
            & \begin{equation}\frac{u(\pi,\tau )}{R T} = \tau \gamma_{\tau} \end{equation} \\ \bottomrule
\end{tabular}
\end{table}

It now looks like this:

However, the right equations are too low - I want them to be in the middle of the cell (see original example).

Answer 1

You can use m-type columns and flalign for left aligning the numbered equation. Some vertical space corrections are needed, but they're hidden in a macro, so you don't need to specify them each time.

\documentclass{report}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[ngerman]{babel}

\usepackage[intlimits]{amsmath} 
\usepackage{booktabs,array}
\usepackage{caption}

\newcommand{\tableequation}[1]{%
  \vspace*{-\baselineskip}
  {\begin{flalign}#1&&&\end{flalign}}%
  \vspace*{-\baselineskip}
}

\begin{document}

With a reference to one of the equations, \eqref{eq-sV}

\begin{table}[htb]
\centering

\caption{testststt} \label{tab_BG1_zustand}

\begin{tabular}{
  @{}
  >{\linespread{1.2}\selectfont}m{6cm}
  @{}
  m{6cm}
  @{}
}
\toprule
Zustandsgröße &  Beziehung \\
\midrule 

spezifisches Volumen\newline
$v = (\partial g / \partial p)_T$ &
  \tableequation{
    v(\pi,\tau)\frac{p}{R T} = \pi \gamma_{\pi} \label{eq-sV}
  } \\

spezifische innere Energie\newline
$u=g-T(\partial g / \partial T)_p - p(\partial g / \partial p)_T$ &
  \tableequation{
    \frac{u(\pi,\tau )}{R T} = \tau \gamma_{\tau}
  } \\
\bottomrule
\end{tabular}

\end{table}

\end{document}

Answer 2

Some variations of Kormylo's answer:

• The cells in the left column uses an inner tabular. The second line is indented to emphasize the term in the first line.
• No fixed column widths.
• The equation numbers can be referenced, using amsmath macros for the formatting of the equation number.

Full example:

\documentclass{report}
\usepackage[utf8]{inputenc}
\usepackage[intlimits]{amsmath}
\usepackage{caption}
\usepackage{booktabs}

\begin{document}
\begin{table}
  \centering
  \caption{testststt}
  \label{tab_BG1_zustand}
  \newcommand*{\SetEqNum}{%
    \refstepcounter{equation}%
    \thetag\theequation
  }
  \newcommand*{\DisplayEq}[1]{%
    \ensuremath{\displaystyle #1}%
  }
  \newcommand*{\DefEq}[2]{%
    \begin{tabular}{@{}l@{}}%
      #1\\
      \quad\DisplayEq{#2}%
    \end{tabular}%
  }
  \begin{tabular}{llr}
    \toprule
    Zustandsgröße &  Beziehung
    \\ \midrule
    \DefEq{spezifisches Volumen}{v = (\partial g / \partial p)_T}
    & \DisplayEq{v(\pi,\tau)\frac{p}{R T} = \pi \gamma_{\pi}}
    & \SetEqNum\label{eq:Volumen}
    \\
    \addlinespace
    \DefEq{spezifische innere Energie}
          {u=g-T(\partial g / \partial T)_p - p(\partial g / \partial p)_T}
    & \DisplayEq{\frac{u(\pi,\tau )}{R T} = \tau \gamma_{\tau}}
    & \SetEqNum\label{eq:InnereEnergie}
    \\ \bottomrule
  \end{tabular}
\end{table}

In der Tabelle~\ref{tab_BG1_zustand} gibt es die Beziehungen
\eqref{eq:Volumen} und~\eqref{eq:InnereEnergie}.
\end{document}

Answer 3

The p{6cm} is equivalent to \parbox[t]{6cm}, but \parbox[c]{6cm} would do better for this. Nor do you really need a display math environment when $\displaystyle ...$ will do. Especially, if you put the equation number into its own column.

\documentclass{report}

\usepackage[intlimits]{amsmath} 
\usepackage{here}           
\usepackage{floatflt}
\usepackage{caption}
\usepackage{listliketab}
\usepackage{tabularx}
\usepackage{booktabs}

\begin{document}
\begin{table}[htb]
\caption{testststt} \label{tab_BG1_zustand}
  \begin{tabular}{llr}
        \toprule
        Zustandsgröße &  Beziehung \\ \midrule 
       \parbox[c]{6cm}{\text{spezifisches Volumen} \newline
         $\displaystyle v = (\partial g / \partial p)_T$}
        & \parbox[c]{6cm}{$\displaystyle v(\pi,\tau)\frac{p}{R T} = \pi \gamma_{\pi}$}
        & \stepcounter{equation}(\theequation) 
        \\[5mm]
       \parbox[c]{6cm}{\text{spezifische innere Energie} \newline
         $\displaystyle u=g-T(\partial g / \partial T)_p - p(\partial g / \partial p)_T$}
        & \parbox[c]{6cm}{$\displaystyle \frac{u(\pi,\tau )}{R T} = \tau \gamma_{\tau}$}
        & \stepcounter{equation}(\theequation)
        \\ \bottomrule
  \end{tabular}
\end{table}
\end{document}

Answer 4

Here is a way. I used threeparttable in order to have the caption left-aligned w.r.t. the table. Off topic: you shouldn't load here since float defines an H option.

\documentclass{report}
\usepackage[utf8]{inputenc}
\usepackage{lmodern}
\usepackage[german]{babel}
\usepackage[showframe, nomarginpar]{geometry}
\usepackage[intlimits]{mathtools}
\usepackage{nccmath}
\usepackage{floatflt}
\usepackage{caption}
\usepackage{booktabs}
\usepackage{array, caption, threeparttable}
\newcolumntype{M}[1]{>{\fleqn}m{#1} <{\endfleqn}}

\begin{document}

\vspace*{1\baselineskip}
\begin{table}[!htb]
  \centering
  \captionsetup{singlelinecheck=off}
  \begin{threeparttable}
    \caption{testststt} \label{tab_BG1_zustand}
    \setlength\abovedisplayskip{-2ex}
    \setlength\belowdisplayskip{-1.5ex}
    \begin{tabular}{M{6cm} M{6cm}}
      \toprule
      Zustandsgröße & Beziehung \\ \midrule
      \begin{fleqn}\begin{gather*}
      \shortintertext{spezifisches Volumen}
      v =(∂ g / ∂ T)_T\end{gather*}\vskip-\abovedisplayskip\end{fleqn}
                      & \begin{equation}\displaystyle v(π,τ)\frac{p}{R T} = π e γ_{π}\end{equation} \\
      \begin{fleqn}\begin{gather*}
      \shortintertext{spezifische innere Energie}
      u = g- T (∂ g / ∂ T)_p- p(∂ g / ∂ T)_T \end{gather*}\end{fleqn}
                      & \begin{equation}
      \frac{u(π, τ)}{RT} = τ γ_{τ}
      \end{equation}\\
      \bottomrule
    \end{tabular}
  \end{threeparttable}
\end{table}

\end{document}