Hat over < symbol

Question

I want to put a hat over < symbol. I have tried \widehat{<} and \hat{<}, but neither of them are working. How can I do this?

P.S. I am using Overleaf

Edit I am using \usepackage[spanish]{babel}. That seems to be the problem, because if I don't include this package, \widehat{<} adn \hat{<} work smoothly. How can I solve my problem while using the babel package?

@kubo Does \documentclass{article}\begin{document}$\hat{<}\widehat{<}$\end{document} not give you what you are looking for? — Dan, Nov 13 '21 at 17:23
@Dan Yes, it does. However, I am using \usepackage[spanish]{babel}. That seems to be the problem. How can I solve it? — kubo, Nov 13 '21 at 17:32
@kubo The babel package doesn't give me a problem. (Try \documentclass{article}\usepackage[spanish]{babel}\begin{document}$\hat{<}\widehat{<}$\end{document}) What other packages are you using? It could be helpful if you added a minimum working example of your code that generates the issue to your question. — Dan, Nov 13 '21 at 17:35
Outside math mode, < occupies the character position of the inverted exclamation mark. Perhaps this is related? — Heiko Theißen, Nov 13 '21 at 18:49
You might try adding a command to access the < character implicitly. See this relevant solution: https://tex.stackexchange.com/questions/298172/command-for-and-in-mathmode.
Placing \newcommand{\lt}{\symbol{"3C}} in the preamble and using either $\widehat{\lt}$ or $\hat{\lt}$ works for me, even with \usepackage[spanish]{babel}. Of course, this may get cumbersome if you have to do something similar for several other symbols, but it is a start. — jasonhathcock, Nov 13 '21 at 19:29

egreg · Accepted Answer · 2021-11-14T00:07:00.600

4

I believe this should be reported as a bug in babel-spanish.

Anyway, since typing \widehat{<} is not really good because it will produce wrong spaces, you can use a workaround: define a command before the special action of babel-spanish enters the scene.

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage[spanish]{babel}
\newcommand{\lesshat}{\mathrel{\widehat{<}}}
\begin{document}
$a<b\lesshat c$
\end{document}

If you want to type \hat{<} or \widehat{<} in the body of the document, you can't unless you load

\usepackage[spanish,es-noquoting]{babel}

but, as I said at the beginning, this would produce wrong spacing because \hat{<} would be considered an ordinary symbol.

Thanks to Dan for pointing out that in a former version of the answer \string was not needed.

edited Nov 14 '21 at 00:07

answered Nov 13 '21 at 22:31

egreg

1,121,712

2

In English, "hatless" means "without a hat", so this command name rather contradicts itself, although unintentionally. – barbara beeton Nov 13 '21 at 22:37
@barbarabeeton Right. I'll reverse. I guess that \lesshat will raise less eyebrows. – egreg Nov 13 '21 at 22:40
Good choice. (By the way, the pedant in me says that should be "fewer eyebrows". But it's not otherwise confusing.) – barbara beeton Nov 13 '21 at 22:45
Well if you want to raise eyebrows, one could read \lesshat as Les shat. He might have done so on Pen Island. – Don Hosek Nov 13 '21 at 22:56
@Dan Yes, that's right, because only < is made active, not >, by babel-spanish. – egreg Nov 13 '21 at 23:40
@egreg Sorry, I mis-typed > instead of < in my comment, but for me both (<,>) still work fine without es-noquoting. – Dan Nov 13 '21 at 23:48
@egreg \documentclass{article}\usepackage[spanish]{babel}\begin{document}$\hat{<}\widehat{<}$\end{document} for instance compiles just fine. – Dan Nov 13 '21 at 23:55
@Dan Doh! Yes, now I know why. – egreg Nov 14 '21 at 00:03

score 3 · Answer 2 · answered Nov 13 '21 at 23:03

I add my solution with the option \selectlanguage{spanish} that not give no error of compilation.

\documentclass[a4paper,12pt]{article}
\usepackage[T1]{fontenc}
\usepackage[spanish]{babel}
\selectlanguage{spanish}
\DeclareMathAccent{\widehat}{\mathord}{largesymbols}{98}
\begin{document}
[f(x)<g(x)\mathrel{\widehat{<}}h(x)]
\end{document}

Hat over < symbol

2 Answers2