Never seen such a symbol, but you can define it; choose a better name.
\documentclass{article}
\usepackage{centernot}
\newcommand{\wrel}{% for ``weird relation''
\centernot{\mathrel{-}\joinrel\mathrel{-}}%
}
\begin{document}
\[
W\wrel X
\]
\end{document}

Notes. I use the fact that TeX doesn't add space between consecutive relation symbols; \joinrel
is a little negative space that counts as a relation symbol. Thus we get two superimposing minus signs (just like what's done for longer arrows). With \centernot
we place the \not
symbol exactly in the middle.
A different version using /
instead of \not
, so also \backslash
can be employed instead.
\documentclass{article}
\makeatletter
\newcommand{\centersymbol}[2]{%
\mathrel{\vphantom{#1#2}\mathpalette\center@symbol{{#1}{#2}}}%
}
\newcommand{\center@symbol}[2]{%
\center@@symbol{#1}#2%
}
\newcommand{\center@@symbol}[3]{%
\ooalign{\hss$#1\m@th#2$\hss\cr\hss$#1\m@th#3$\hss\cr}%
}
\makeatother
\newcommand{\wrel}{\centersymbol{/}{\mathrel{-}\joinrel\mathrel{-}}}
\newcommand{\lerw}{\centersymbol{\backslash}{\mathrel{-}\joinrel\mathrel{-}}}
\begin{document}
\[
W\wrel X \lerw Y
\]
\end{document}

233F
-- "apl functional symbol slash bar", although for that symbol, the slash is a lot longer. (the version with the backslash is2340
-- "apl functional symbol backslash bar".) since the referenced paper is on interpreters and programming languages, apl fits in that category. then thexits
fonts would be relevant.