tags: LaTeX xy-pic

最近抽时间绘制了一下下面这个图[^1]:

这是我绘制的图: (有点丑, 但是这不重要了)

部分代码如下:

\documentclass[border=3pt]{standalone}
% \input xypic
\usepackage[all,pdf]{xy}
\newcommand{\B}{{\dir{*}}}
\begin{document}
    \begin{xy}\drop[*1]\xybox{
            (0,0)="A" *{\B}*\cir{},
            (5,8.66)="B" *{\B}*\cir{},
            (10,0)="C" *{\B}*\cir{},
            (20,0)="D" *{\B}*\cir{},
            {"A";"B":"C";"B",x} ="I" *{},
            "I";"A"**{}  **@{-},
            "I";"C"**{}  **@{-}}
        \end{xy}
\end{document}

\documentclass[border=3pt]{standalone}
% \input xypic
\usepackage[all,pdf]{xy}
\newcommand{\B}{{\dir{*}}}
\newcommand{\C}{\circ}
\def\al{\ar@{-}}
\def\xyy{\xymatrix@1}

\begin{document}
    \xyy{*=0{\B}\al[d]\al[dr]&*=0{\B}\al[d]\\*=0{\B}&*=0{\B}}
\end{document}

费了不少功夫, 之后再抽空讲解一下代码吧. 主要就是参考了xypic-guide和xypic-refer[^2][^3].

[^1]: Enumerative Combinatorics: Volume 1 (Cambridge Studies in Advanced Mathematics, Series Number 49): Stanley, Richard P.: 9781107602625: Amazon.com: Books;

[^2]:XY-pic Reference Manual - TeXDochttp://texdoc.net › doc › generic › xypic › xyrefer;

[^3]:XY-pic User's Guide - TeXDochttps://texdoc.org › serve › xyguide.pdf;