如何在 eqnarray* 内框化公式

Question

如何装箱公式，例如

\begin{eqnarray*}
&&P(X_{n+1} = i_{n+1}\mid
X_{0}=i_{0}, X_{1}=i_{1},\ldots,X_{n-1}=i_{n-1},X_{n}=i_{n}) \\
&&=P(X_{n+1}=i_{n+1}\mid X_{n}=i_{n}).
\end{eqnarray*}

我使用amsmath包

\begin{eqnarray*}
p(x) &= 3x^6 + 14x^5y + 590x^4y^2 + 19x^3y^3\\
&- 12x^2y^4 - 12xy^5 + 2y^6 - a^3b^3
\end{eqnarray*}

Answer 1

以下是两个版本empheq：tcolorbox

\documentclass{article}
\usepackage{mathtools}
\usepackage{empheq}
\usepackage[most]{tcolorbox}
\begin{document}


%\begin{eqnarray*}
%&&P(X_{n+1} = i_{n+1}\mid
%X_{0}=i_{0}, X_{1}=i_{1},\ldots,X_{n-1}=i_{n-1},X_{n}=i_{n}) \\
%&&=P(X_{n+1}=i_{n+1}\mid X_{n}=i_{n}).
%\end{eqnarray*}

\begin{empheq}[box=\fbox]{align*}
   &P(X_{n+1} = i_{n+1}\mid X_{0}=i_{0}, X_{1}=i_{1},\dots,X_{n-1}=i_{n-1},X_{n}=i_{n}) \\
  ={}&P(X_{n+1}=i_{n+1}\mid X_{n}=i_{n})
\end{empheq}

\begin{tcolorbox}[ams align*,colback=white!40!yellow]
   &P(X_{n+1} = i_{n+1}\mid X_{0}=i_{0}, X_{1}=i_{1},\dots,X_{n-1}=i_{n-1},X_{n}=i_{n}) \\
  ={}&P(X_{n+1}=i_{n+1}\mid X_{n}=i_{n})
\end{tcolorbox}


\end{document}