如何在对齐环境中仅枚举一行

Question

我有这个

\begin{align} \label{computation-one}
       &\langle \tilde{\overline{\nabla}}_{\tilde{e}_i} \tilde{\textbf{S}}, \tilde{e}_j \rangle^2 + 
       \langle \tilde{\overline{\nabla}}_{e^{-f}\tilde{e}_0} \tilde{\textbf{S}}, e^{-f}\tilde{e}_0 
       \rangle^2 + \sum\limits_{i=1}^n \tilde{R}(\tilde{e}_i, \tilde{\textbf{S}}, \tilde{\textbf{S}}, 
       \tilde{e}_i) + \tilde{R}(e^{-f}\tilde{e}_0, \tilde{\textbf{S}}, \tilde{\textbf{S}}, e^{- 
       f}\tilde{e}_0)\\
       &= \langle \overline{\nabla}_{e_i} \textbf{S}, e_j \rangle^2 + \sum\limits_{i=1}^n R(e_i, 
       \textbf{S}, \textbf{S}, e_i) - \sum\limits_{\alpha,\beta=n+1}^{n+p} S^{\alpha}S^{\beta} 
       \overline{\nabla}_{\alpha} \overline{\nabla}_{\beta} f + e^{-4f} \left( 
       \sum\limits_{\alpha=n+1}^{n+p} S^{\alpha} \tilde{h}^{\alpha}_{00} \right)^2\\
       &- \sum\limits_{\alpha,\beta=n+1}^{n+p} S^{\alpha}S^{\beta} \overline{\nabla}_{\alpha} f 
       \overline{\nabla}_{\beta} f.
\end{align}

这使

但我希望有这个

我怎样才能做到这一点？

提前致谢！

Answer 1

我建议您将aligned环境嵌套在equation环境中。这样，如果您决定将方程编号放在底部而不是顶部，只需将其替换为\begin{aligned}[t]即可\begin{aligned}[b]。

我还建议您加载该mathtools包并使用其\smashoperator宏来缩小某些术语的间距\sum。

\documentclass{article}
\usepackage{mathtools,amssymb}
\usepackage{newtxtext,newtxmath} %optional (Times Roman font)
\begin{document}
\begin{equation}\label{computation-one}
\begin{aligned}[t]
&\langle \tilde{\overline{\nabla}}_{\!\tilde{e}_i}  
         \tilde{\mathbf{S}}, \tilde{e}_j \rangle^2 
+\langle \tilde{\overline{\nabla}}_{\!e^{-f}\!\tilde{e}_0} 
    \tilde{\mathbf{S}}, e^{-f}\!\tilde{e}_0 \rangle^2 
+ \sum_{i=1}^n \tilde{R}
  (\tilde{e}_i, \tilde{\mathbf{S}}, \tilde{\mathbf{S}}, \tilde{e}_i) 
+ \tilde{R}
  (e^{-f}\!\tilde{e}_0, \tilde{\mathbf{S}}, \tilde{\mathbf{S}}, e^{-f}\!\tilde{e}_0) \\
&\quad= \langle \overline{\nabla}_{\!e_i} \mathbf{S}, e_j \rangle^2 
+ \sum_{i=1}^n R(e_i, \mathbf{S}, \mathbf{S}, e_i) - 
\smashoperator{\sum_{\alpha,\beta=n+1}^{n+p}} S^{\alpha}S^{\beta} 
       \overline{\nabla}_{\!\alpha} \overline{\nabla}_{\!\beta} f 
+ e^{-4f} \biggl( \smashoperator[r]{\sum_{\alpha=n+1}^{n+p}} 
    S^{\alpha} \tilde{h}^{\alpha}_{00} \biggr)^2 \\
&\qquad- \smashoperator{\sum_{\alpha,\beta=n+1}^{n+p}} 
S^{\alpha}S^{\beta} \, 
\overline{\nabla}_{\!\alpha} f\, \overline{\nabla}_{\!\beta}  f\,.  
\end{aligned}
\end{equation}

\end{document}