# \xmapsto shows a “7” at the beginning of the arrow

I am using XeTeX and need a text above the \mapsto arrow. So I googled for it and found the command for it. But unfortunately, this comes out:

So here's the code:

\documentclass[a4paper,10pt]{scrartcl}
\usepackage{unicode-math}
\usepackage[leqno]{mathtools}
\begin{document}
\begin{align*}
F:\;\mathbb{K}^n \xmapsto{A} \mathbb{K}^m
\end{align*}
\end{document}

• okay wait ill edit – Lillien Sabrina Gluch Jul 7 '18 at 13:41
• Don't use fontenc with XeTeX or LuaTeX. (That does not solve your issue here, but you should still not do load fontenc.) – moewe Jul 7 '18 at 13:43
• Although I use text in the document? I am writing my math lectures in one document and there are explanations. But thank you for the tip – Lillien Sabrina Gluch Jul 7 '18 at 13:44
• Given that you're using XeLaTeX, why are you loading the times and lmodern packages? – Mico Jul 7 '18 at 13:51
• Really? It doesn't work for me. Please post an answer if you got this to work. BTW: I just noticed that you already got an answer that suggested to load unicode-math after amssymb and other math-related packages (tex.stackexchange.com/q/434645/35864). You should definitely consider following the advice you get in answers. – moewe Jul 7 '18 at 14:26

So this worked out for me:

\documentclass[a4paper,10pt]{scrartcl}
\usepackage{unicode-math}
\usepackage[leqno]{mathtools}
\DeclareSymbolFont{pazosymbols}{OMS}{zplm}{m}{n}
\makeatletter
\ExplSyntaxOn %define \xmapsto
\DeclareMathSymbol \c_pazo_minus \mathbin { pazosymbols } 0
\DeclareMathSymbol \c_pazo_mapstochar \mathrel { pazosymbols } { "37 }
\DeclareMathSymbol \c_pazo_rightarrow \mathrel { pazosymbols } { "21 }
\cs_new_protected_nopar:Nn \pazo_relbar: {
\mathrel {
\mathpalette \mathsm@sh \c_pazo_minus
}
}
\cs_set_protected_nopar:Nn \MT_mapsto_fill: {
\arrowfill@ { \c_pazo_mapstochar \pazo_relbar: } \pazo_relbar: \c_pazo_rightarrow
}
\ExplSyntaxOff
\makeatother
\begin{document}
\begin{align*}
F:\;\mathbb{K}^n \xmapsto{A} \mathbb{K}^m
\end{align*}
\end{document}


If you are willing to use LuaLaTeX:

\documentclass[a4paper,10pt]{scrartcl}
\usepackage[leqno]{mathtools}
\usepackage{unicode-math}

\makeatletter
\renewcommand{\xmapsto}[2][]{\mathrel{\mathpalette\xmapsto@{{#1}{#2}}}}
\newcommand{\xmapsto@}[2]{\xmapsto@@{#1}#2}
\newcommand{\xmapsto@@}[3]{%
\begingroup
\sbox\z@{$\m@th#1\mathop{}\limits_{\;#2\;}^{\;#3\;}$}%
\mathop{\Uhextensible width \wd\z@ 0 "27FC}_{#2}^{#3}%
\endgroup
}
\makeatother

\begin{document}
\begin{gather*}
F\colon\mathbb{K}^n \xmapsto{A} \mathbb{K}^m \\
A \xmapsto[aaaaa]{bbbbbbbbbb} B
\end{gather*}
\end{document}


On the other hand, \mapsto is normally used not to denote a map with domain and codomain, but its action on elements.