答案1
这是一种可能性,中间有一个非常小的符号。
\documentclass{article}
\usepackage{amsmath}
\usepackage{pict2e}
\makeatletter
\newcommand{\adjunction}[4]{%
% #1 : #2 <arrows> #3 : #4
#1\colon #2%
\mathrel{\vcenter{%
\offinterlineskip\m@th
\ialign{%
\hfil$##$\hfil\cr
\longrightharpoonup\cr
\noalign{\kern-.3ex}
\smallbot\cr
\longleftharpoondown\cr
}%
}}%
#3 \noloc #4%
}
\newcommand{\longrightharpoonup}{\relbar\joinrel\rightharpoonup}
\newcommand{\longleftharpoondown}{\leftharpoondown\joinrel\relbar}
\newcommand\noloc{%
\nobreak
\mspace{6mu plus 1mu}
{:}
\nonscript\mkern-\thinmuskip
\mathpunct{}
\mspace{2mu}
}
\newcommand{\smallbot}{%
\begingroup\setlength\unitlength{.15em}%
\begin{picture}(1,1)
\roundcap
\polyline(0,0)(1,0)
\polyline(0.5,0)(0.5,1)
\end{picture}%
\endgroup
}
\makeatother
\begin{document}
\[
\adjunction{F}{\mathcal{C}}{\mathcal{D}}{G}
\]
\end{document}
\adjunction*
您可以选择使用 将标签放置在上方和下方的版本。
\documentclass{article}
\usepackage{amsmath}
\usepackage{pict2e}
\makeatletter
\newcommand{\adjunction}{\@ifstar\named@adjunction\normal@adjunction}
\newcommand{\normal@adjunction}[4]{%
% #1 : #2 <arrows> #3 : #4
#1\colon #2%
\mathrel{\vcenter{%
\offinterlineskip\m@th
\ialign{%
\hfil$##$\hfil\cr
\longrightharpoonup\cr
\noalign{\kern-.3ex}
\smallbot\cr
\longleftharpoondown\cr
}%
}}%
#3 \noloc #4%
}
\newcommand{\named@adjunction}[4]{%
% #1 : #2 <arrows> #3 : #4
#2%
\mathrel{\vcenter{%
\offinterlineskip\m@th
\ialign{%
\hfil$##$\hfil\cr
\scriptstyle#1\cr
\noalign{\kern.1ex}
\longrightharpoonup\cr
\noalign{\kern-.3ex}
\smallbot\cr
\longleftharpoondown\cr
\scriptstyle#4\cr
}%
}}%
#3%
}
\newcommand{\longrightharpoonup}{\relbar\joinrel\rightharpoonup}
\newcommand{\longleftharpoondown}{\leftharpoondown\joinrel\relbar}
\newcommand\noloc{%
\nobreak
\mspace{6mu plus 1mu}
{:}
\nonscript\mkern-\thinmuskip
\mathpunct{}
\mspace{2mu}
}
\newcommand{\smallbot}{%
\begingroup\setlength\unitlength{.15em}%
\begin{picture}(1,1)
\roundcap
\polyline(0,0)(1,0)
\polyline(0.5,0)(0.5,1)
\end{picture}%
\endgroup
}
\makeatother
\begin{document}
\[
\adjunction{F}{\mathcal{C}}{\mathcal{D}}{G}
\]
\[
\adjunction*{F}{\mathcal{C}}{\mathcal{D}}{G}
\]
\end{document}