如何使公式环境中的文本居中？

Question

因此我制作了一些较长的逻辑语句，如代码所示：

\documentclass[12 pt,handout,notheorems]{beamer}
\usepackage{pgfpages}
\pgfpagesuselayout{resize to}[a4paper,landscape]
\usetheme{Boadilla}
\usefonttheme{professionalfonts} %To get the accents aligned correctly, albeit in Computer Modern Roman
\usepackage{amsmath}
\usepackage{mleftright}
\usefonttheme{structuresmallcapsserif}
\mleftright
\begin{document}
    \begin{frame}
        In conclusion,
        \begin{itemize}
            \item For minimum-time problems:
            \begin{equation*}
                \begin{aligned}
                    &\text{System is controllable}\\
                    &\text{with respect to }u_i
                \end{aligned}
                \iff \text{Singular arcs do not exist.}
            \end{equation*}
            \item For minimum-time-fuel problems (also applies for minimum-fuel problems):
            \begin{equation*}
                \begin{aligned}
                    &\text{System is not controllable}\\
                    &\text{with respect to }u_i\\
                    &\text{or}\\
                    &\det\left(A\right) = 0
                \end{aligned}
                \implies \text{Singular arcs exist.}
            \end{equation*}
        \end{itemize}
    \end{frame}
\end{document}

如何使带圆圈的内容居中对齐（或正确格式化）？

Answer 1

您可以使用array。

\documentclass[12 pt,handout,notheorems]{beamer}
\usepackage{mathtools}
\usepackage{pgfpages}
\pgfpagesuselayout{resize to}[a4paper,landscape]
\usetheme{Boadilla}
\usefonttheme{professionalfonts} %To get the accents aligned correctly, albeit in Computer Modern Roman
\usepackage{amsmath}
\usepackage{mleftright}
\usefonttheme{structuresmallcapsserif}
\mleftright
\begin{document}
    \begin{frame}
        In conclusion,
        \begin{itemize}
            \item For minimum-time problems:
            \begin{equation*}
            \begin{array}{@{}c@{}}
                    \text{System is controllable}\\
                    \text{with respect to }u_i
            \end{array}
                \iff \text{Singular arcs do not exist.}
            \end{equation*}
            \item For minimum-time-fuel problems (also applies for minimum-fuel problems):
            \begin{equation*}
                \begin{array}{@{}c@{}}
                    \text{System is not controllable}\\
                    \text{with respect to }u_i\\
                    \text{or}\\
                    \det\left(A\right) = 0
                \end{array}
                \implies \text{Singular arcs exist.}
            \end{equation*}
        \end{itemize}
    \end{frame}
    \begin{frame}
        In conclusion,
        \begin{itemize}
            \item For minimum-time problems:
            \begin{equation*}
             \left.\begin{array}{@{}c@{}}
                    \text{System is controllable}\\
                    \text{with respect to }u_i
                \end{array}\right\}
                \iff \text{Singular arcs do not exist.}
            \end{equation*}
            \item For minimum-time-fuel problems (also applies for minimum-fuel problems):
            \begin{equation*}
              \left.\begin{array}{@{}c@{}}
                    \text{System is not controllable}\\
                    \text{with respect to }u_i\\
                    \text{or}\\
                    \det\left(A\right) = 0
               \end{array}\right\}
                \implies \text{Singular arcs exist.}
            \end{equation*}
        \end{itemize}
    \end{frame} 
\end{document}

Answer 2

您可以将aligned环境替换为gathered环境 -- 并删除&对齐点。与基于 - 的解决方案的主要区别array在于，内容默认以显示数学模式排​​版，这意味着行距略有增加。

\documentclass[12pt,handout,notheorems]{beamer}
\usepackage{pgfpages}
\pgfpagesuselayout{resize to}[a4paper,landscape]
\usetheme{Boadilla}
\usefonttheme{professionalfonts}
\usefonttheme{structuresmallcapsserif}
\usepackage{amsmath} % for 'gathered' environment
\usepackage{mleftright}\mleftright

\begin{document}
    \begin{frame}
        In conclusion,
        \begin{itemize}
            \item For minimum-time problems:
            \begin{equation*}
                \begin{gathered}
                    \text{System is controllable}\\
                    \text{with respect to $u_i$}
                \end{gathered}
                \iff \text{Singular arcs do not exist.}
            \end{equation*}
            \item For minimum-time-fuel problems (also applies for minimum-fuel problems):
            \begin{equation*}
                \begin{gathered}
                    \text{System is not controllable}\\
                    \text{with respect to $u_i$, or}\\
                    \det\left(A\right) = 0
                \end{gathered}
                \implies \text{Singular arcs exist.}
            \end{equation*}
        \end{itemize}
    \end{frame}
\end{document}

Answer 3

您可以使用\parbox，但您需要指定宽度。我使用了\widthofcalc 包中的 ，但您不必那么精确。请注意，这\parbox会使您退出数学模式。

\documentclass[12 pt,handout,notheorems]{beamer}
\usepackage{pgfpages}
\pgfpagesuselayout{resize to}[a4paper,landscape]
\usetheme{Boadilla}
\usefonttheme{professionalfonts} %To get the accents aligned correctly, albeit in Computer Modern Roman
\usepackage{amsmath}
\usepackage{mleftright}
\usefonttheme{structuresmallcapsserif}
\mleftright
\usepackage{calc}
\begin{document}
    \begin{frame}
        In conclusion,
        \begin{itemize}
            \item For minimum-time problems:
            \begin{equation*}
                \parbox{\widthof{System is controllable}}{\centering
                    System is controllable with respect to $u_i$}
                \iff \text{Singular arcs do not exist.}
            \end{equation*}
            \item For minimum-time-fuel problems (also applies for minimum-fuel problems):
            \begin{equation*}
                \parbox{\widthof{System is not controllable}}{\centering
                    System is not controllable with respect to $u_i$ or
                    $\det\left(A\right) = 0$}
                \implies \text{Singular arcs exist.}
            \end{equation*}
        \end{itemize}
    \end{frame}
\end{document}