如何在 tikz 图片中绘制这个图形。有人可以提供给我它的代码吗？
答案1
尝试这个代码
\documentclass{article}
\usepackage{pgf,tikz}
\usetikzlibrary{positioning,shapes,fit,calc}
\begin{document}
\begin{tikzpicture}
\tikzset{Point/.style={draw,fill,circle=0.5mm,inner sep=0.5mm}}
\node[Point, label={[right,name={L11}]:$U_{1,1}$}](u11){};
\node[Point,below=1em of u11, label={[right,name=L12]:$U_{1,2}$}](u12){};
\node[Point,below=1em of u12, label={[right,name=L13]:$U_{1,3}$}](u13){};
\node[fit=(u11)(u12)(u13)(L11)(L12)(L13),ellipse,draw,label={$U1$}](u1){};
\node[Point, below=6em of u13,label={[right,name={L21}]:$U_{2,1}$}](u21){};
\node[Point,below=1em of u21, label={[right,name=L22]:$U_{2,2}$}](u22){};
\node[Point,below=1em of u22, label={[right,name=L23]:$U_{2,3}$}](u23){};
\node[fit=(u21)(u22)(u23)(L21)(L22)(L23),ellipse,draw,label={$U2$}](u2){};
\node[fit=(u1)(u2),draw, ellipse,label=U]{};
\begin{scope}[xshift=15em]
\node[Point, label={[right,name={L11}]:$V_{1,1}$}](v11){};
\node[Point,below=1em of v11, label={[right,name=L12]:$V_{1,2}$}](v12){};
\node[Point,below=1em of v12, label={[right,name=L13]:$V_{1,3}$}](v13){};
\node[Point,below=1em of v13, label={[right,name=L14]:$V_{1,4}$}](v14){};
\node[fit=(v11)(v12)(v13)(v14)(L11)(L12)(L13)(L14),ellipse,draw,label={$V1$}](v1){};
\node[Point, below=8em of v13,label={[right,name={L21}]:$V_{2,1}$}](v21){};
\node[Point,below=1em of v21, label={[right,name=L22]:$V_{2,2}$}](v22){};
\node[Point,below=1em of v22, label={[right,name=L23]:$V_{2,3}$}](v23){};
\node[fit=(v21)(v22)(v23)(L21)(L22)(L23),ellipse,draw,label={$V2$}](v2){};
\node[fit=(v1)(v2),draw, ellipse,label=V]{};
\end{scope}
\draw (u1) -- (v12);
\draw (u2) -- (v12);
\end{tikzpicture}
\end{document}
