表格错误

Question

我想要达到以下结果。

我编写了以下代码，但它给出了错误。我认为问题出在新命令上。（我是定义新命令的新手，因此请提供一些解释）

\usepackage{array}
\usepackage{booktabs}

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

\begin{document}
\begin{tabular} {
@{}
>{\linespread{1.2}\selectfont}m{6cm}
@{}
m{6cm}
@{}
}
\toprule
\multicolumn{2}{ |l| }{\textbf{Requirements of inner product}}\\
\midrule
\emph{Commutative:} & \tableequation{ \textbf{u} \cdot \textbf{v} = \textbf{v} \cdot \textbf{u}, }\\
\emph{Nonnegative:} & 
\tableequation{ 
\textbf{u} \cdot \textbf{u} &> 0 && \text{for all \textbf{u} \ne 0, }\\ 
&=0 && \text{for \textbf{u} = 0,}\\ 
}\\
\emph{Linear:} & \tableequation{ (\alpha \textbf{u} + \beta \textbf{v}) \cdot \textbf{w} = \alpha(\textbf{u} \cdot \textbf{w}) + \beta(\textbf{v} \cdot \textbf{w}), }
\bottomrule
\end{tabular} 
\end{document}

Answer 1

您不需要tabular环境即可获得此结果：alignat可以轻松完成。我建议使用第二种变体，代码更简单，在我看来，它看起来更好：

\documentclass{article}

\usepackage{mathtools} %requirement for the flalign environment
\usepackage{array}
\usepackage{booktabs}

\begin{document}

\begin{subequations}
  \setlength{\aboverulesep}{1ex}
  \setlength{\belowrulesep}{1ex}
  \begin{alignat}{3}
    \toprule
    \shortintertext{\bfseries\MakeUppercase{Requirements of inner product}\smallskip}
    \emph{Commutative:} & \qquad & \mathbf{u} · \mathbf{v} & {}={} & & \mathbf{v} · \mathbf{u}, \\
    \emph{Nonnegative:} & & \mathbf{u} · \mathbf{u} > 0 & & & \text{for all } \mathbf{u} \ne 0, \notag \\
                        & & = 0 & & & \text{for } \mathbf{u} = 0 \\
    \emph{Linear:} & & (α\mathbf{u} + β\mathbf{v}) · \mathbf{w} & {}={} & & α(\mathbf{u} · \mathbf{w}) + β(\mathbf{v} · \mathbf{w}), \\
    \bottomrule\notag
  \end{alignat}
\end{subequations}

\begin{subequations}
  \setlength{\aboverulesep}{1ex}
  \setlength{\belowrulesep}{1ex}
  \begin{alignat}{2}
    \toprule
    \shortintertext{\bfseries\MakeUppercase{Requirements of inner product}\smallskip}
    \emph{Commutative:} & \qquad & \mathbf{u} · \mathbf{v} & = \mathbf{v} · \mathbf{u}, \\
    \emph{Nonnegative:} & & \mathbf{u} · \mathbf{u} & > 0 \quad\text{for all } \mathbf{u} \ne 0, \notag \\
                        & & & = 0 \quad \text{for } \mathbf{u} = 0 \\
    \emph{Linear:} & & (α\mathbf{u} + β\mathbf{v}) · \mathbf{w} & = α(\mathbf{u} · \mathbf{w}) + β(\mathbf{v} · \mathbf{w}), \\
    \bottomrule\notag
  \end{alignat}
\end{subequations}

\end{document} 

Answer 2

您需要amsmathflalign 环境。此外，您的 bottomrule 之前缺少一个\\，请参阅内联注释：

\documentclass{article}
\usepackage{amsmath} %requirement for the flalign environment
\usepackage{array}
\usepackage{booktabs}

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

\begin{document}
\begin{tabular} {
@{}
>{\linespread{1.2}\selectfont}m{6cm}
@{}
m{6cm}
@{}
}
\toprule
\multicolumn{2}{ |l| }{\textbf{Requirements of inner product}}\\
\midrule
\emph{Commutative:} & \tableequation{ \textbf{u} \cdot \textbf{v} = \textbf{v} \cdot \textbf{u}, }\\
\emph{Nonnegative:} & 
\tableequation{ 
\textbf{u} \cdot \textbf{u} &> 0 && \text{for all \textbf{u} \ne 0, }\\ 
&=0 && \text{for \textbf{u} = 0,}\\ 
}\\
\emph{Linear:} & \tableequation{ (\alpha \textbf{u} + \beta \textbf{v}) \cdot \textbf{w} = \alpha(\textbf{u} \cdot \textbf{w}) + \beta(\textbf{v} \cdot \textbf{w}), }\\ %missing \\ in the original code
\bottomrule
\end{tabular} 
\end{document}

Answer 3

一些建议：第一个有点复杂，因为我们需要模拟booktabs但使用flalign。第二个更自然。我删除了其中一个条件，因为它遵循最后一个条件。

\documentclass{article}
\usepackage{amsmath}
\usepackage{booktabs,array}

\usepackage{lipsum} % just for the example

\begin{document}

\lipsum[2]
\begin{center}
\begin{minipage}{\textwidth}% don't break

\setlength{\abovedisplayskip}{0pt}
\setlength{\belowdisplayskip}{0pt}
\newcommand{\eqsep}{\mathrel{\hphantom{=}}}

\hrule height \heavyrulewidth
\vspace{\belowrulesep}
\textbf{Requirements of inner product}

\vspace{\aboverulesep}
\hrule height \lightrulewidth
\vspace{\belowrulesep}
\begin{flalign}
&\text{\emph{Commutative}:} & 
  \mathbf{u} \cdot \mathbf{v}     &= \mathbf{v} \cdot \mathbf{u}, &\\
&\text{\emph{Nonnegative}:} & 
  \mathbf{u} \cdot \mathbf{u} > 0 &\eqsep \text{for all $\mathbf{u} \ne 0$, } &\nonumber\\ 
&&
                           {} = 0 &\eqsep \text{for $\mathbf{u} = 0$,} &\\ 
&\text{\emph{Linear}:} &
  (\alpha \mathbf{u} + \beta \mathbf{v}) \cdot \mathbf{w} &= 
    \alpha(\mathbf{u} \cdot \mathbf{w}) + \beta(\mathbf{v} \cdot \mathbf{w}). &
\end{flalign}

\vspace{\aboverulesep}
\hrule height \heavyrulewidth
\end{minipage}
\end{center}
\lipsum[3]
\[
\newcommand{\eqsep}{\mathrel{\hphantom{=}}}
\newcommand{\addnumber}{\refstepcounter{equation}(\theequation)}
\setlength{\tabcolsep}{0pt}
\begin{tabular*}{\textwidth}{
  @{\extracolsep{\fill}}
  l
  >{$}r<{$}@{\extracolsep{0pt}}
  >{${}}c<{{}$}
  >{$}l<{$}@{\extracolsep{\fill}}
  r
}
\toprule
\multicolumn{5}{c}{\bfseries Requirements of inner product}\\
\midrule
\emph{Commutative} & 
  \mathbf{u} \cdot \mathbf{v} &= &\mathbf{v} \cdot \mathbf{u}, & \addnumber \\
\addlinespace
\emph{Positive}: & 
  \mathbf{u} \cdot \mathbf{u} > 0 & &\text{for all $\mathbf{u} \ne 0$, } & \addnumber \\
\addlinespace
\emph{Linear}: &
  (\alpha \mathbf{u} + \beta \mathbf{v}) \cdot \mathbf{w} &= &
  \alpha(\mathbf{u} \cdot \mathbf{w}) + \beta(\mathbf{v} \cdot \mathbf{w}). & \addnumber \\
\bottomrule
\end{tabular*}
\]
\lipsum[3]

\end{document}

之后您可以根据需要\addnumber添加。\label