# How can I write a reflected \sqrt operator?

How can I produce this symbol in LaTeX? It is used in Galois theory for p-adic fields to denote a root of the equation X^{p}-X-a with a \in k, and being k a p-adic field. I have tried a lot of different things like rotatebox or reflect box, but I can't produce the same output.

• Welcome to TeX SX! Are p and a part of the symbol (what does it denote, by the way)? – Bernard Aug 22 '17 at 15:07
• If I could obtain a command (for instance named "modified") and obtain the output writing \modified[p]{a} it would be nice, but it doesn´t matter really, I only need to obtain the same output. – matemagreek Aug 22 '17 at 15:10
• It´s usually used in Galois theory of p-adic field, to denote a rooth of the equation $X^{p}-X-a$ with $a\in k$, and being $k$ a $p$-adic field. – matemagreek Aug 22 '17 at 15:11
• Will a always be a single letter or may it be a longer expression? – Bernard Aug 22 '17 at 15:16
• if this is an "accepted" symbol (i.e., it has appeared in a publication reviewed for mathscinet), and you can provide a citation of where it appears, i can submit it to be considered for inclusion in unicode. the best documentation shows the symbol in a context that clarifies its meaning and usage. – barbara beeton Aug 22 '17 at 18:53

\documentclass{article}
\usepackage{graphicx}
\newcommand\reflectsqrt[2][\relax]{
\ifx\relax#1
\scalebox{1}[-1]{$\sqrt{\scalebox{1}[-1]{$#2$}}$}
\else
\scalebox{1}[-1]{$\sqrt[{\scalebox{1}[-1]{% \raisebox{-4pt}{$\scriptscriptstyle#1$}}}]{\scalebox{1}[-1]{$#2$}}$}
\fi
}
\begin{document}
$x\reflectsqrt{a}$

$x\reflectsqrt[p]{a_3 + b^3}$
\end{document}


With stackengine:

\documentclass{article}

\usepackage{stackengine}
\newlength\rlength

\stackMath\stackinset{c}{}{c}{-1.3ex}{\scriptscriptstyle#1}%
{\raisebox{-0.6ex}{\Large$\wedge$}}\mkern-2mu\rlap{\rule[-0.68ex]{\rlength}{0.5pt}}%
\mkern1mu#2}

\begin{document}

$\padicroot{p}{y}$%

\end{document}


• Hoist by my own petard! +1 – Steven B. Segletes Aug 22 '17 at 16:02
• I must say I was surprised you didn't use your own package ;o) I also thought of a solution like yours, but finally opted for this one as more flexible. – Bernard Aug 22 '17 at 16:07
• You should edit your answer so that it does not require rightward scrolling. Just sayin' – Steven B. Segletes Aug 22 '17 at 16:14