方程线之间的距离

方程线之间的距离
\documentclass{article}
%%\usepackage[utf8]{inputenc} % that's the default nowadays
\usepackage{mathtools}
\usepackage{dsfont}
\usepackage{amsmath}

\begin{document}
\begin{align*}
\label{eq6.1}
    \norm{\lambda_{r,\theta}(z)}_{d+1}^{d+1}:=\sum \limits_{\theta,z}\lambda_{r,\theta}^{d+1}(z)=
\end{align*}    
\begin{align*}
&=\sum \limits_{\theta,z}|\{(u_1,\dots,u_{d+1},v_1,\dots,v_{d+1})\in \mathcal{E}^{2d+2}: u_1-\sqrt{r}\theta v_1=\dots=u_{d+1}-\sqrt{r}\theta v_{d+1}=z\}|=\\
&=\sum \limits_{\theta}|\{(u_1,\dots,u_{d+1},v_1,\dots,v_{d+1})\in \mathcal{E}^{2d+2}: u_i-u_j=\sqrt{r}\theta(v_i-v_j),\ 1\leq i<j\leq d+1\}|.
\end{align*}

\end{document}

此代码代表以下公式

在此处输入图片描述

我想知道如何使第一行和第二行之间的距离更小?

答案1

我建议您 (a) 使用单个align*环境而不是两个连续的align*环境,以及 (b) 使用\MoveEqLeft宏(由包提供mathtools)将第一行“推”到最左边,并让以下行相对于第一行缩进。

在此处输入图片描述

\documentclass{article} 

\usepackage{mathtools} % for \DeclarePairedDelimiter and \MoveEqLeft macros
\DeclarePairedDelimiter{\norm}{\lVert}{\rVert}
\DeclarePairedDelimiter{\abs}{\lvert}{\rvert}

%%\usepackage{dsfont}  % \mathds not used in this test document
%%\usepackage{amsmath} % amsmath is loaded automatically by mathtools

\begin{document}

\begin{align*} 
%\label{eq6.1} %% '\label' is not useful in unnumbered equations
\MoveEqLeft[1]{
\norm[\big]{\lambda_{r,\theta}(z)}_{d+1}^{d+1}
\coloneqq\sum_{\theta,z}\lambda_{r,\theta}^{d+1}(z)} \\
&=\sum_{\theta,z}
  \abs[\big]{ \bigl\{
  (u_1,\dots,u_{d+1},v_1,\dots,v_{d+1}) \in \mathcal{E}^{2d+2}: 
   u_1-\sqrt{r}\theta v_1 = \dots = u_{d+1}-\sqrt{r}\theta v_{d+1} = z
  \bigr\} }\\
&=\sum_{\theta}
  \abs[\big]{ \bigl\{
  (u_1,\dots,u_{d+1},v_1,\dots,v_{d+1}) \in \mathcal{E}^{2d+2}: 
  u_i-u_j=\sqrt{r}\theta(v_i-v_j),\ 
  1\leq i<j\leq d+1
  \bigr\} }\,.
\end{align*}

\end{document}

附录为了解决 OP 的后续查询:为了使第一行居中,同时将接下来的两行对齐在其=符号上,我建议您在环境中嵌入一个align*环境gather*

\begin{gather*} 
\norm[\big]{\lambda_{r,\theta}(z)}_{d+1}^{d+1}
\coloneqq\sum_{\theta,z}\lambda_{r,\theta}^{d+1}(z) \\
\begin{align*}
&=\sum_{\theta,z}
  \abs[\big]{ \bigl\{
  (u_1,\dots,u_{d+1},v_1,\dots,v_{d+1}) \in \mathcal{E}^{2d+2}: 
   u_1-\sqrt{r}\theta v_1 = \dots = u_{d+1}-\sqrt{r}\theta v_{d+1} = z
  \bigr\} }\\
&=\sum_{\theta}
  \abs[\big]{ \bigl\{
  (u_1,\dots,u_{d+1},v_1,\dots,v_{d+1}) \in \mathcal{E}^{2d+2}: 
  u_i-u_j=\sqrt{r}\theta(v_i-v_j),\ 
  1\leq i<j\leq d+1
  \bigr\} }\,.
\end{align*}
\end{gather*}

第二附录,以解决 OP 关于对所讨论的三个方程进行编号的后续问题。要对所有三个方程进行编号,只需删除初始附录中显示的带有gather*和环境的和环境。如果您只想对所讨论的三个方程中的部分方程进行编号,请根据需要添加(或)指令。例如,要使所有三个方程看起来都共享一个共同的单个方程编号,请向第一个和第三个方程添加指令。align*gatheralign\notag\nonumber\notag

\documentclass{article}
\usepackage[letterpaper,margin=1in]{geometry} % set page parameters as needed
\usepackage{mathtools} % for \DeclarePairedDelimiter macro
\DeclarePairedDelimiter{\norm}{\lVert}{\rVert}
\DeclarePairedDelimiter{\abs}{\lvert}{\rvert}

\begin{document}
\begin{gather} 
  \norm[\big]{\lambda_{r,\theta}(z)}_{d+1}^{d+1}
    \coloneqq\sum_{\theta,z}\lambda_{r,\theta}^{d+1}(z) \\
  \begin{align}
  &=\sum_{\theta,z}
    \abs[\big]{ \bigl\{
    (u_1,\dots,u_{d+1},v_1,\dots,v_{d+1}) \in \mathcal{E}^{2d+2}: 
     u_1-\sqrt{r}\theta v_1 = \dots = u_{d+1}-\sqrt{r}\theta v_{d+1} = z
    \bigr\} }  \\
  &=\sum_{\theta}
    \abs[\big]{ \bigl\{
    (u_1,\dots,u_{d+1},v_1,\dots,v_{d+1}) \in \mathcal{E}^{2d+2}: 
    u_i-u_j=\sqrt{r}\theta(v_i-v_j),\ 
    1\leq i<j\leq d+1
    \bigr\} } \,.
  \end{align}
\end{gather}
\end{document}

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