4

I stumbled across this line in chktex (here) with a note saying

This is a warning which you may ignore, but for maximum aestethic pleasure, you should enclose your bracket characters with `{}'s.

What happens (technically) if I add these brackets?

The following MWE shows the difference with and without the additional brackets; note that the version with the additional brackets results in the superscript being a little bit higher (which, according to chktex seems to be preferred?).

\documentclass{scrartcl}
\title{}
\begin{document}

\begin{equation}
\{X\}^T
{\{X\}}^T
\end{equation}

\end{document}

enter image description here

  • 3
    That's simply wrong advice. Complain with the developers of chktex. If you want to avoid the wrong warning, use \lbrace X\rbrace^T. – egreg Feb 25 at 13:11
  • So the slightly higher superscript is not desired? – dpaetzel Feb 25 at 13:15
12

Apparently, the developer of chktex advises to always do something like

{(a+b)}^2

which is not what's normally done. There's no need for it and the output is very disputable in typographic terms: compare by yourself, left the normal, right the braced combo:

\documentclass{article}
\begin{document}

\begin{equation}
(a+b)^2 \quad {(a+b)}^2
\end{equation}

\begin{equation}
(\sqrt{2}+1)^2 \quad {(\sqrt{2}+1)}^2
\end{equation}

\end{document}

enter image description here

The second one is obviously wrong. The warnings of chktex are

Warning 3 in badchk.tex line 5: You should enclose the previous parenthesis with `{}'.
(a+b)^2 \quad {(a+b)}^2
    ^
Warning 3 in badchk.tex line 9: You should enclose the previous parenthesis with `{}'.
(\sqrt{2}+1)^2 \quad {(\sqrt{2}+1)}^2
           ^

and I heartily disagree.

|improve this answer|||||
  • On one hand it is uglier with the dynamically scaling exponent height, but on the other hand semantically in tex (a+b)^2 means that the right parenthesis has a superscript, rather than the whole expression, which makes me feel unclean. – SamYonnou Feb 25 at 22:49
  • @SamYonnou Don't feel unclean. That's how it has been done for a few centuries. The exponent is indeed to the whole expression delimited by the parenthesis: no need to add levels. – egreg Feb 25 at 22:49
  • I mean in tex as a computer language specifically, not in conventional mathematical notation – SamYonnou Feb 25 at 22:51
  • @SamYonnou Really, that's the way it should be done. Braces around math material make a subformula, where spaces are frozen and other things happen. Sometimes it's useful, generally it isn't. – egreg Feb 25 at 22:54
1

Using braces seems to be either irrelevant or bad.

In display mode,

\documentclass{article}

\begin{document}

\begin{equation}
\left(\sqrt 2 + 1\right)^2 = {\left(\sqrt 2 +1\right)}^2
\end{equation}

\end{document}

enter image description here

the result is identical.

Inline, using braces disturbs the interline spacing.

No braces (\sqrt 2 + 1)^2:

enter image description here

Braces {(\sqrt 2 + 1)}^2:

enter image description here

Conclusion: disable chktex Warning 3 permanently.

|improve this answer|||||

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.