如何在案例中使用 argmax 或 argmin？

Question

我想在我的 Beamer Slide 中使用 argmax。我发现这个问题非常有用： argmin 或 argmax 的命令？ 问题是我无法\argmax在案例环境中使用。

示例 1： \argmax在案例之外工作正常：

\documentclass[demo]{beamer}% <-- demo only for test, delete it in real document
\mode<presentation> {
    \usetheme{Madrid}
    \setbeamertemplate{footline}[page number]
}

\usepackage{booktabs}           % Allows the use of \toprule,
% \midrule and \bottomrule in tables
\usepackage{tikz}               % add background image
\usepackage{mathtools}               % add background image
\DeclareMathOperator*{\argmax}{arg\,max}
\begin{document}
    \begin{frame}
        \frametitle{Solving MDP 2}
        \begin{block}{Optimal Policy}
            Optimal policy can be found by maximizing over $q_\ast (s,a)$
            \begin{equation*}
            \pi_\ast (a|s)=
            \begin{cases*}
            1 & \text{if }  (s,a) \\
            0 &  \text{otherwise}

            \end{cases*}
        \argmax_{x \in A}  q_\ast(s,a)          
          \end{equation*}

        \end{block}
    \end{frame}
\end{document}

示例 2：内部情况\argmax不工作

 \documentclass[demo]{beamer}% <-- demo only for test, delete it in real document
\mode<presentation> {
    \usetheme{Madrid}
    \setbeamertemplate{footline}[page number]
}

\usepackage{booktabs}           % Allows the use of \toprule,
% \midrule and \bottomrule in tables
\usepackage{tikz}               % add background image
\usepackage{mathtools}               % add background image
\DeclareMathOperator*{\argmax}{arg\,max}
\begin{document}
    \begin{frame}
        \frametitle{Solving MDP 2}
        \begin{block}{Optimal Policy}
            Optimal policy can be found by maximizing over $q_\ast (s,a)$
            \begin{equation*}
            \pi_\ast (a|s)=
            \begin{cases*}
            1 & \text{if } \argmax_{x \in A}  q_\ast(s,a)  \\
            0 &  \text{otherwise}

            \end{cases*}

            \end{equation*}

        \end{block}
    \end{frame}
\end{document}

Answer 1

避免在数学显示中出现空行。

您可以使用\limits

\documentclass[demo]{beamer}% <-- demo only for test, delete it in real document
\mode<presentation> {
    \usetheme{Madrid}
    \setbeamertemplate{footline}[page number]
}

\usepackage{booktabs}           % Allows the use of \toprule,
% \midrule and \bottomrule in tables
\usepackage{tikz}               % add background image
\usepackage{mathtools}               % add background image
\DeclareMathOperator*{\argmax}{arg\,max}
\begin{document}

    \begin{frame}
        \frametitle{Solving MDP 2}
        \begin{block}{Optimal Policy}
            Optimal policy can be found by maximizing over $q_\ast (s,a)$
            \begin{equation*}
            \pi_\ast (a|s)=
            \begin{cases*}
            1 & if $\argmax\limits_{x \in A}  q_\ast(s,a)$  \\
            0 & otherwise
            \end{cases*}
            \end{equation*}
        \end{block}
    \end{frame}
\end{document}

回想一下，cases*右栏是以文本模式启动的。