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帮助提供简单的 tikzpicture（数学证明）

tag-icon • tag-icon tikz-pgf tikz-arrows circles
帮助提供简单的 tikzpicture（数学证明）

我完全不知道该如何制作这张（我猜）相当简单的图片。任何帮助都将不胜感激在此处输入图片描述

答案1

\documentclass[tikz,border=2mm]{standalone}

\begin{document}

    \begin{tikzpicture}
        \node[draw,circle,minimum width=2cm] at (0,0) (A) {};
        \node[above] at (A.north) {$A$};
        \draw (A.west) -- (A.east);
        \path (A.center) -- node{$A-T$} (A.north);
        \path (A.center) -- node{$T$} (A.south);

        \node[draw,circle,minimum width=2cm] at (4,0) (B) {};
        \node[above] at (B.north) {$B$};
        \draw (B.west) -- (B.east);
        \path (B.center) -- node{$B-f(T)$} (B.north);
        \path (B.center) -- node{$f(T)$} (B.south);

        \draw[>=latex,->] (B.north west) to [in=20,out=160] node[above] {$g$} (A.north east);
        \draw[>=latex,->] (A.south east) to [in=200,out=340] node[below] {$f$} (B.south west);
    \end{tikzpicture}

\end{document}

在此处输入图片描述

编辑：箭头的起点和终点都在圆圈内，箭头现在位于中间

通过使用该calc库，可以计算箭头的起始（和终止）位置。例如，($(B.north east)!.8!(B.north west)$)表示：箭头起始位置在 80% 处(B.north east)，(B.north west)

使用该decorations.markings库可以改变箭头的位置。

\documentclass[tikz,border=2mm]{standalone}
\usetikzlibrary{calc,decorations.markings}

\begin{document}
    \tikzset{->-/.style={decoration={markings,mark=at position #1 with {\arrow{>}}},postaction={decorate}}}
    \begin{tikzpicture}
        \node[draw,circle,minimum width=2cm] at (0,0) (A) {};
        \node[above] at (A.north) {$A$};
        \draw (A.west) -- (A.east);
        \path (A.center) -- node{$A-T$} ($(A.north)!.3!(A.center)$);
        \path (A.center) -- node{$T$} ($(A.south)!.3!(A.center)$);

        \node[draw,circle,minimum width=2cm] at (4,0) (B) {};
        \node[above] at (B.north) {$B$};
        \draw (B.west) -- (B.east);
        \path (B.center) -- node{$B-f(T)$} ($(B.north)!.3!(B.center)$);
        \path (B.center) -- node{$f(T)$} ($(B.south)!.3!(B.center)$);

        \draw[>=latex,->-=.5] ($(B.north east)!.8!(B.north west)$) to [in=20,out=160] node[above] {$g$} ($(A.north east)!.2!(A.north west)$);
        \draw[>=latex,->-=.5] ($(A.south east)!.2!(A.south west)$) to [in=200,out=340] node[below] {$f$} ($(B.south west)!.2!(B.south east)$);
    \end{tikzpicture}

\end{document}

在此处输入图片描述

答案2

使用 Ti钾Z，这可能看起来像这样：

% arara: pdflatex

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{shapes,positioning,decorations.markings}
\tikzset{%
    ,mynode/.style={circle split,draw, minimum size=2.05cm,text height=\heightof{$f$},text depth=\depthof{g}}
    ,->-/.style={%
        decoration={%
            ,markings
            ,mark=at position #1 with {\arrow{>}}}
        ,postaction={decorate}
        ,shorten >=-3pt,shorten <=-3pt
    }
}

\begin{document}
    \begin{tikzpicture}
    \node [mynode,label=90:$A$] (Anode) {$A-T$ \nodepart{lower} $\vphantom{f(}T$};   
    \node [mynode,label=90:$B$,right = of Anode] (Bnode) {$B-f(T)$ \nodepart{lower} $f(T)$};    
    \draw[->-=.53] (Anode) to [bend right=20] node[below]{$f$} (Bnode);
    \draw[->-=.53] (Bnode) to [bend right=20] node[above]{$g$} (Anode);
    \end{tikzpicture}
\end{document}

在此处输入图片描述

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