如何在函数映射中对齐这些对象

Question

我正在尝试编写一个三组之间的函数映射。我想在第二个环境中保持第一个“数组”环境的对齐，因为我希望最后两行箭头的尖端和尾部与前一个箭头的尖端和尾部对齐。同样，变量“I”和“h”应该接触我在此屏幕截图中绘制的红线：

梅威瑟：

\documentclass{article}

\usepackage{newpxtext}
\usepackage{newpxmath}

\usepackage{amsmath}
\usepackage{mathtools}
\usepackage{stmaryrd}

\makeatletter
 \newcommand{\xmapsfrom}[2][]{%
    \ext@arrow3095\leftarrowfill@{#1}{#2}\mapsfromchar
}
\makeatother

\begin{document}
 \[
  \begin{array}{c}
   \begin{array}{ccccc}
    \{\text{Ideali massimali di $\mathcal{A}$}\} & \longleftrightarrow & \{\text{Ultrafiltri di $\mathcal{A}$}\} & \longleftrightarrow & S(\mathcal{A}) \\
    I & \longmapsto & \{x \in A \colon x^\mathbf{c} \in I\} && \\
    \{x \in A \colon x^\mathbf{c} \in F\} & \longmapsfrom & F & \longmapsto & h_F \\
    && \{x \in A \colon h(x) = 1\} & \longmapsfrom & h
   \end{array} \\
   \begin{array}{ccc}
    I & \xmapsto{\hphantom{aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa}} & h_I \\
    \{x \in A \colon h(x) = 0\} & \xmapsfrom{\hphantom{aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa}} & h
   \end{array}
  \end{array}
 \]
\end{document}

Answer 1

您可以使用单一array环境并将长箭头放置在三个中央列中\multicolumn。

\documentclass[11pt]{article}

\usepackage{newpxtext}
\usepackage{newpxmath}

\usepackage{amsmath}
\usepackage{mathtools}
\usepackage{stmaryrd}

\makeatletter
 \newcommand{\xmapsfrom}[2][]{%
    \ext@arrow3095\leftarrowfill@{#1}{#2}\mapsfromchar
}
\makeatother

\begin{document}
  \[
   \begin{array}{ccccc}
    \{\text{Ideali massimali di $\mathcal{A}$}\} & \longleftrightarrow & \{\text{Ultrafiltri di $\mathcal{A}$}\} & \longleftrightarrow & S(\mathcal{A}) \\
    I & \longmapsto & \{x \in A \colon x^\mathbf{c} \in I\} && \\
    \{x \in A \colon x^\mathbf{c} \in F\} & \longmapsfrom & F & \longmapsto & h_F \\
    && \{x \in A \colon h(x) = 1\} & \longmapsfrom & h \\
    I & \multicolumn{3}{c}{\xmapsto{\hspace{12.5em}}} & h_I \\
    \{x \in A \colon h(x) = 0\} & \multicolumn{3}{c}{\xmapsfrom{\hspace{12.5em}}} & h
   \end{array}
 \]
\end{document}

array由于单列环境（c其中放置实际值）没有用处array，因此我将其删除。此外，根据@Davislor在评论中的建议，我将 都更改\hphantom{aa...aa}为\hspace{12.5em}。

Answer 2

alignat*和 的解决方案eqparbox：

\documentclass{article}

\usepackage{newpxtext}
\usepackage{newpxmath}
\usepackage{mathtools}
\usepackage{stmaryrd}
\usepackage{eqparbox}
\newcommand{\eqmathbox}[2][M]{\eqmakebox[#1]{$\displaystyle#2$}}

\makeatletter
 \newcommand{\xmapsfrom}[2][]{%
 \ext@arrow3095\leftarrowfill@{#1}{#2}\mapsfromchar
}
\makeatother

\begin{document}

 \begin{alignat*}{3}
  \eqmathbox[S]{\{\text{Ideali massimali di }\mathcal{A}\}} & \longleftrightarrow \eqmathbox[M]{\{\text{Ultrafiltri di $\mathcal{A}$}\}} \longleftrightarrow{} && \eqmathbox[D]{S(\mathcal{A})} \\
  \eqmathbox[S]{ I} & \xmapsto{\phantom{\longleftrightarrow}} \eqmathbox[M]{\{x \in A \colon x^\mathbf{c} \in I\}} && \\
   \eqmathbox[S]{ \{x \in A \colon x^\mathbf{c} \in F\}} & \xmapsfrom{\phantom{\longleftrightarrow}} \eqmathbox[M]{F} \xmapsto{\phantom{\longleftrightarrow}} & & \eqmathbox[D]{h_F} \\
  &\phantom{{}\longleftrightarrow{}}\eqmathbox[M]{\{x \in A \colon h(x) = 1\}}\xmapsfrom{\phantom{\longleftrightarrow}} && \eqmathbox[D]{h} \\
    \eqmathbox[S]{I} & \xmapsto{\hphantom{\displaystyle{\longleftrightarrow}\eqmathbox[M]{}{\longleftrightarrow}}} & & \eqmathbox[D]{h_I} \\
    \eqmathbox[S]{\{x \in A \colon h(x) = 0\}} & \xmapsfrom{\hphantom{\displaystyle{\longleftrightarrow}\eqmathbox[M]{}{\longleftrightarrow}}} & & \eqmathbox[D]{h}
 \end{alignat*}

\end{document}