我怎样才能减少两个突出显示的语句之间的“垂直空间”？

Question

\documentclass[11pt,a4paper]{article}
\usepackage{blindtext}
\usepackage{mathtools}
\usepackage{amsmath}
\usepackage{IEEEtrantools}

\begin{document}
\vspace{-1em}
\begin{flalign*}
\times a^{m}\times a^{n-m}&=\times a^{n};\,\text{(By case already proved)}&\\
\times a^{m}\times a^{n-m}\div a^{n-m}&=\times a^{n}\div a^{n-m};\,\text{(Axiom)}&\\
\times a^{m}&=\times a^{n}\div a^{n-m};\,\text{(Definition of division)}&\\
\times a^{m}\div a^{n}&=\times a^{n}\div a^{n-m}\div a^{n};\,\text{(Axiom)}&\\
\times a^{m}\div a^{n}&=\times a^{n}\div a^{n}\div a^{n-m};
\intertext{(The law of commutation for multiplication and division)}
\end{flalign*}
\end{document}

Answer 1

使其成为方程组的一部分，并<len>在中使用负垂直跳跃\\[<len>]：

\documentclass{article}

\usepackage{amsmath}

\begin{document}

\begin{flalign*}
  \times a^{m}\times a^{n-m}             &= \times a^{n};                       && \text{(By case already proved)} \\
  \times a^{m}\times a^{n-m}\div a^{n-m} &= \times a^{n}\div a^{n-m};           && \text{(Axiom)} \\
  \times a^{m}                           &= \times a^{n}\div a^{n-m};           && \text{(Definition of division)} \\
  \times a^{m}\div a^{n}                 &= \times a^{n}\div a^{n-m}\div a^{n}; && \text{(Axiom)} \\
  \times a^{m}\div a^{n}                 &= \times a^{n}\div a^{n}\div a^{n-m}; \\[-\belowdisplayskip]
  \intertext{(The law of commutation for multiplication and division)}
\end{flalign*}

\end{document}

等式中最后一个注释的上方向上移动了-\belowdisplayskip。您可以根据需要进行调整。

Answer 2

由于您加载，因此mathtools您可以简单地使用\shortintertext而不是\intertext。我添加了一个建议来改进方程式的布局（至少对我来说是这样），定义一个commenteq命令：

\documentclass[11pt,a4paper]{article}
\usepackage{blindtext}
\usepackage{mathtools}
\usepackage{amsmath}
\usepackage{IEEEtrantools}
\newcommand\commenteq[1]{\text{\footnotesize(#1)}}

\begin{document}
\vspace{-1em}
\begin{flalign*}
   × a^{m} × a^{n-m}&= × aⁿ;\,\text{(By case already proved)}&\\
   × a^{m} × a^{n-m}\div a^{n-m}&= × aⁿ\div a^{n-m};\,\text{(Axiom)}&\\
   × a^{m}&= × aⁿ\div a^{n-m};\,\text{(Definition of division)}&\\
   × a^{m}\div aⁿ&= × aⁿ\div a^{n-m}\div aⁿ;\,\text{(Axiom)}&\\
   × a^{m}\div aⁿ&= × aⁿ\div aⁿ\div a^{n-m};
  \shortintertext{(The law of commutation for multiplication and division)}
\end{flalign*}

\begin{flalign*}
  {} × a^{m} × a^{n-m}&= × aⁿ; && \commenteq{By case already proved}\\
  {} × a^{m} × a^{n-m}\div a^{n-m}&= × aⁿ\div a^{n-m}; && \commenteq{Axiom}\\
  {} × a^{m}&= × aⁿ\div a^{n-m}; & &\commenteq{Definition of division}\\
  {} × a^{m}\div aⁿ&= × aⁿ\div a^{n-m}\div aⁿ; && \commenteq{Axiom}\\
  {} × a^{m}\div aⁿ&= × aⁿ\div aⁿ\div a^{n-m};
  \shortintertext{(The law of commutation for multiplication and division)}
\end{flalign*}
\end{document}