generated at
一致数え上げ
\forall n\in\Nと任意の半順序集合Uに対して、全単射単調写像\varphi:\underline U⤖[1..n]一致数え上げと呼ぶ
[a..b]:=[a,b]\cap\Nとした
[1..n]の順序は、自然数の順序とする
有限集合の定義より、一致数え上げがある半順序集合は必ず有限順序集合となる

名前の意味
\le_Uの並びに反しないように\underline Uの要素と自然数とを対応付けている
\le_\bullet\bulletの順序
つまり、\le_Uの並びに一致させて数え上げるということ

このHasse図で定義される順序集合に対して、\begin{array}{c|cccccc}u&1&2&3&4&5&6\\\hline \varphi(u)&a&d&b&e&c&f\end{array}で定義される\varphiは一致数え上げになる
\varphiの順に赤くなるようにした
numbering.tikz(tex)
\usetikzlibrary{animations} \begin{document} \begin{tikzpicture}[domain=0:4] \tikzset{ every node/.style={circle,draw,inner sep=2pt,fill=white,font=\Large}, every path/.style={very thick}, animate={ a:fill={0s="white",1s={jump,"transparent"},7s={jump,"red"},repeats}, a:draw={0s="white",1s={jump,"white"} ,7s={jump,"red"},repeats}, d:fill={0s="white",2s={jump,"transparent"},7s={jump,"red"},repeats}, d:draw={0s="white",2s={jump,"white"} ,7s={jump,"red"},repeats}, b:fill={0s="white",3s={jump,"transparent"},7s={jump,"red"},repeats}, b:draw={0s="white",3s={jump,"white"} ,7s={jump,"red"},repeats}, e:fill={0s="white",4s={jump,"transparent"},7s={jump,"red"},repeats}, e:draw={0s="white",4s={jump,"white"} ,7s={jump,"red"},repeats}, c:fill={0s="white",5s={jump,"transparent"},7s={jump,"red"},repeats}, c:draw={0s="white",5s={jump,"white"} ,7s={jump,"red"},repeats}, f:fill={0s="white",6s={jump,"transparent"},7s={jump,"red"},repeats}, f:draw={0s="white",6s={jump,"white"} ,7s={jump,"red"},repeats}, }, } \def\s{2}; \coordinate (up) at (\s*2^-0.5,\s*2^-0.5); \coordinate (down) at (\s*2^-0.5,\s*-2^-0.5); \draw (0,0) node[label={right:$a$}](a){} -- ++(up) node[label={right:$b$}](b){} -- ++(up) node[label={right:$c$}](c){} -- ++(down) node[label={right:$e$}](e){} -- ++(up) node[label={right:$f$}](f){}; \draw (b) -- ++(down) node[label={right:$d$}](d){} -- (e); \end{tikzpicture} \end{document}