[Tex/LaTex] How to get the covering relation symbol

symbols

I want   cover to denote the covering relation. I can't find this symbol in my standard sources for this sort of thing. Detextify has also failed in this. How can I get this relational symbol?

Best Answer

If you can't use unicode-math, here you find a couple of possibilities:

\documentclass{article}
\usepackage{amsmath}
\usepackage{pict2e,picture}

\newcommand{\coveringA}{%
  \mathrel{-\mkern-4mu}<%
}
\newcommand{\coveringB}{\mathrel{\text{$\vcenter{\hbox{\pictcoveringB}}$}}}

\newcommand{\pictcoveringB}{%
  \begin{picture}(1em,.5em)
  \roundcap
  \put(0,.25em){\line(1,0){.6em}}
  \put(.6em,.25em){\line(3,1){.4em}}
  \put(.6em,.25em){\line(3,-1){.4em}}
  \end{picture}%
}

\begin{document}

$x\coveringA y_{\coveringA}$

$x\coveringB y_{\coveringB}$

\end{document}

enter image description here

If you're sure that you won't use the symbol in subscripts or superscripts, then 

\newcommand{\coveringB}{\mathrel{\vcenter{\hbox{\pictcoveringB}}}}

is more efficient. You can play with the parameters as you wish, in the second solution.

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