定义中行与行之间的间距过大

Question

我有一个定义，其中使用了一些数学文本。行与行之间的间距对我来说太大了，我的编辑器也将其列为坏框。我使用的 LaTeX 代码是：

\begin{defn} An \emph{affine combination} of points $x_1, x_2, \ldots, x_k$ is given by $\sum\limits_{i=1}^k \lambda_{i}x_{i}$, where $\lambda_1,\ldots, \lambda_k \ \in \mathbb{R}$ and $\sum\limits_{i=1}^k \lambda_{i} = 1$. A set of points is said to be \emph{affinely independent} if no point is an affine combination of the others.
\end{defn}

我得到的输出是：

有人能帮我缩小线条之间的间隙吗？谢谢！

Answer 1

警告：这不是通用解决方案。这是在完成大部分文档后应用的解决方案。

正如评论中提到的那样，您可以通过删除以下内容来解决此问题\limits：

\documentclass{article}
\usepackage{amsmath,amssymb,amsthm}
\newtheorem{defn}{Definition}
\begin{document}

\begin{defn} 
  An \emph{affine combination} of points $x_1, x_2, \dots, x_k$ 
  is given by $\sum_{i=1}^k \lambda_{i}x_{i}$, where 
  $\lambda_1,\dots, \lambda_k \in \mathbb{R}$ and $\sum_{i=1}^k \lambda_{i} = 1$. 
  A set of points is said to be \emph{affinely independent} if no point is 
  an affine combination of the others.
\end{defn}

\end{document}

如果您坚持按照您设置的限制来做，那么您可以\smash在第一个实例中使用：

\documentclass{article}
\usepackage{amsmath,amssymb,amsthm}
\newtheorem{defn}{Definition}
\begin{document}

\begin{defn} 
  An \emph{affine combination} of points $x_1, x_2, \dots, x_k$ 
  is given by $\smash{\sum\limits_{i=1}^k} \lambda_{i}x_{i}$, where 
  $\lambda_1,\dots, \lambda_k \in \mathbb{R}$ and $\sum\limits_{i=1}^k \lambda_{i} = 1$. 
  A set of points is said to be \emph{affinely independent} if no point is 
  an affine combination of the others.
\end{defn}

\end{document}

结果是

正如@egreg所指出的，\smash，正如 重新定义的amsmath，接受一个可选参数。 要么\smash[b]要么\smash[t]第一个打破垂直深度归零，但不影响高度，第二个打破垂直高度为零，但不影响深度：

\documentclass{article}
\usepackage{amsmath}
\setlength{\fboxsep}{0pt}
\begin{document}

I've set the \verb-\fboxsep- to \verb-0pt-, notice how in the first example, the \verb-\fbox- looks only like a line.
\[
  \text{Smash removing vertical height and depth:} \quad
  \fbox{$\smash{\sum\limits_{i=1}^k}$}
\]

\[
  \text{Smash removing only the vertical depth:} \quad
  \fbox{$\smash[b]{\sum\limits_{i=1}^k}$}
\]


\[
  \text{Smash removing only the vertical height:} \quad
  \fbox{$\smash[t]{\sum\limits_{i=1}^k}$}
\]


\end{document}

在第一个例子中，最后两行看起来有点太接近，因此您可以添加一个支柱（我使用 来完成此操作\rule）：

\documentclass{article}
\usepackage{amsmath,amssymb,amsthm}
\newtheorem{defn}{Definition}
\begin{document}

\begin{defn} 
  An \emph{affine combination} of points $x_1, x_2, \dots, x_k$ 
  is given by $\sum_{i=1}^k \lambda_{i}x_{i}$, where 
  $\lambda_1,\dots, \lambda_k \in \mathbb{R}$ and $\sum_{i=1}^k\rule[-1.25ex]{0pt}{1pt} \lambda_{i} = 1$. 
  A set of points is said to be \emph{affinely independent} if no point is 
  an affine combination of the others.
\end{defn}

\end{document}

Answer 2

必要时进行组合，并对包\smash进行局部轻微修改：\baselineskipsetspace

\documentclass[a4paper]{article}
\usepackage{amsmath, amsfonts}
\usepackage{nccmath}

\setlength\parindent{1em}
\usepackage[thmmarks, amsmath, thref]{ntheorem}
\theoremstyle{plain}
\theoremheaderfont{\upshape\bfseries}
\theorembodyfont{\itshape}
\theoremseparator{.}
\newtheorem{defn}{Definition}
\usepackage{setspace}
\setstretch{1.2}

\begin{document}

\setcounter{defn}{3}
\begin{defn} An \emph{affine combination} of points $x_1, x_2, \ldots, x_k$ is given by $\smash[b]{\sum\limits_{i=1}^k} \lambda_{i}x_{i}$, where $\lambda_1,\ldots, \lambda_k \ \in \mathbb{R}$ and $ \sum\limits_{i=1}^k \lambda_{i} = 1$. A set of points is said to be \emph{affinely independent} if no point is an affine combination of the others.
\end{defn}

\end{document}