6

I have seen people put small question marks over greater than symbols in proofs, however, I'm having trouble doing it over "≥" symbols. Using \stackrel{?}{≥} returns an error:

 Command \> already defined.
               Or name \end... illegal, see p.192 of the manual.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
 ...
l.175 \newcommand{\>}{\stackrel{?}{?}}
?

And using \overset{?}{≥} gives the wrong symbol:

enter image description here

How would we type "≥" in latex without returning a question mark?

3
  • 3
    (1) Welcome, (2) please post a minimal example, just not an image of an error. You are being told you cannot define \<, so find another name for it. In general it is not a good idea to use so short macro names for your own personal macros.
    – daleif
    Oct 14, 2016 at 14:21
  • 5
    Try \newcommand\maybegeq{\stackrel{?}{\geq}}. With the amsmath package, \overset{?}{\geq} works as well. I don't think that you can use the greater-equal unicode character directly.
    – gernot
    Oct 14, 2016 at 14:52
  • @gernot I suggest you make that an answer Nov 4, 2016 at 21:12

2 Answers 2

8

Use \geq instead of and define the command as

\newcommand\maybegeq{\stackrel{?}{\geq}}

or as

\usepackage{amsmath}
\newcommand\maybegeq{\overset{?}{\geq}}

Example:

\documentclass{article}
\usepackage{amsmath}
\begin{document}
$x \stackrel{?}{\geq} y$

$x \overset{?}{\geq} y$
\end{document}

enter image description here

\stackrel and \overset differ in the way they are spaced. \stackrel{a}{b} is a relation no matter what b was (as rel in the macro name suggests), whereas \overset{a}{b} will be treated in the same way as b without \overset. If you want \overset{a}{b} to become a relation, you have to say so explicitly using \mathrel{\overset{a}{b}} or \overset{a}{\mathrel{b}}.

enter image description here

2
  • I believe \overset is preferred to \stackrel (due to better spacing or something).
    – erik
    Nov 4, 2016 at 23:00
  • @erik It depends on what your aim is. I have added an explanation. Thanks for your comment.
    – gernot
    Nov 5, 2016 at 11:45
4

Doing \newcommand{\>}{\stackrel{?}{≥}} obviously produces an error, because \> is an already defined command.

You could do

\renewcommand{\>}{\stackrel{?}{≥}}

but it wouldn't help much, because an input like

$a \> b$

would not print what you'd like to. Even if you load

\usepackage[utf8]{inputenc}

(assuming you're saving your file in UTF-8 encoding) wouldn't be sufficient.

You can use as a shorthand for \geq, by defining an action for the Unicode character (and as well).

\documentclass{article}

\usepackage[utf8]{inputenc}

\usepackage{amsmath}
\usepackage{newunicodechar}

\newunicodechar{≤}{\leq}
\newunicodechar{≥}{\geq}

\begin{document}

\begin{tabular}{cc}
\verb|\stackrel|    & \verb|\overset| \\
$a\stackrel{?}{≤}b$ & $a\overset{?}{≤}b$ \\
$a\stackrel{?}{≥}b$ & $a\overset{?}{≥}b$
\end{tabular}

\end{document}

I'd prefer \overset to \stackrel, because it's more general.

About redefining \> for this purpose, I wouldn't do it. You can rather do

\newcommand{\?}[1]{\overset{?}{#1}}

and input

$a \?{>} b$
$a \?{≥} b$
$a \?{<} b$
$a \?{≤} b$

which is, in my opinion, clearer.

enter image description here

3
  • Is \newcommand{\?}{\overset{?}} in any way preferable?
    – gernot
    Nov 5, 2016 at 11:33
  • @gernot It is essentially equivalent, but less clear. You save a few nanoseconds every time \? is expanded.
    – egreg
    Nov 5, 2016 at 11:38
  • @KedarMhaswade Ask the Unicode Consortium…
    – egreg
    Jan 14, 2023 at 13:20

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