# What LaTeX package do I need to use \questeq?

I want to use the QUESTION EQUAL TO character and the command for it is \questeq. I know that the "category" it is in is mathrel.

• From here: tex.stackexchange.com/a/205131/120578 you can define it using the command \def\questeq{\ensuremath{\stackrel{?}{=}}} Feb 25, 2018 at 1:36
• @koleygr Why\def and \ensuremath? Feb 25, 2018 at 6:12
• @egreg, I can't understand your question. Do you mean why combining \def and \ensuremath? Or why using each one? In first case I don't know the reason to don't do it. In second case: For \def no answer. For \ensuremath to be able to use it in math mode and in text mode. Feb 25, 2018 at 11:18
• @koleygr \def should be \newcommand and the symbol is for math mode, so \ensuremath is unnecessary (and actually wrong). Feb 25, 2018 at 12:33
• @egreg thanks for the comment... The truth is that I am using \def more times than the necessary (that are real few). For \ensuremath I added that on my edit to make sure it works in text mode because I had not seen this symbol used anywhere until now. (I don't really see the purpose of it's usage... but may be could be useful in very special cases) Feb 25, 2018 at 12:56

The packages stix and libertinust1math offer that symbol.
In Lua/XeLaTeX the symbol is additionally available with unicode-math. Check the list of symbols to see which fonts support \questeq.
/usr/local/texlive/2017/texmf-dist/tex/latex $grep -r '\\questeq' stix/stix.sty:\stix@MathSymbol{\questeq} {\mathrel}{integrals}{"90} libertinust1math/libertinust1math.sty:\libus@MathSymbol{\questeq} {\mathrel}{symbols}{"70} unicode-math/unicode-math-table.tex:\UnicodeMathSymbol{"0225F}{\questeq  Otherwise you can build that symbol yourself using the amsmath package. This is not a single symbol though. \documentclass{article} \usepackage{amsmath} \begin{document}$a \overset{?}{=} b\$

• @cfr Okay, maybe my wording was too ambiguous. Of course the traditional font setup also works in Lua/XeLaTeX. Additionally one has the opportunity to use unicode-math with those. I edited my answer accordingly. Feb 25, 2018 at 4:48