垂直对齐应均匀

Question

我想知道如何进行正确对齐，使等分线在垂直方向上均匀分布。

\begin{align*}
\Gamma(\lambda_{1})\Gamma(\lambda_{2})&=\int_{(0,\infty)^{2}}\phi(u,v)\, \mathrm{d}m_{2}(u,v)\\
&\overset{12.15}=\int_{(0,\infty)\times (0,1)}x^{(\lambda_{1}+\lambda_{2})-1}e^{-x}y^{\lambda_{1}-1}(1-y)^{\lambda_{2}-1}\mathrm{d}m_{2}(x,y)\\
&=\int_{0}^{\infty}\int_{0}^{1}x^{(\lambda_{1}+\lambda_{2})-1}e^{-x}y^{\lambda_{1}-1}(1-y)^{\lambda_{2}-1}\mathrm{d}y\mathrm{d}x
\end{align*}`

Answer 1

我只会选择\mathclap过度设置的项目：

\documentclass{article} 
\usepackage{mathtools}

\begin{document}

\begin{align*}
  \Gamma(\lambda_{1})\Gamma(\lambda_{2})&=\int_{(0,\infty)^{2}}\phi(u,v)\, \mathrm{d}m_{2}(u,v)\\
  &\overset{\mathclap{12.15}}{=} \int_{(0,\infty)\times (0,1)}x^{(\lambda_{1}+\lambda_{2})-1}e^{-x}y^{\lambda_{1}-1}(1-y)^{\lambda_{2}-1}\mathrm{d}m_{2}(x,y)\\
  &=\int_{0}^{\infty}\int_{0}^{1}x^{(\lambda_{1}+\lambda_{2})-1}e^{-x}y^{\lambda_{1}-1}(1-y)^{\lambda_{2}-1}\mathrm{d}y\mathrm{d}x
\end{align*}

\end{document}

\mathclap（由...提供mathtools，这将加载amsmath默认情况下）消除其参数的水平宽度。