Crossed NE and SE arrows?

Question

I'm trying to write a piece of code in LaTeX which includes a crossed set of arrows (the \nearrow and \searrow). Here is my code

\documentclass{article}
\begindocument
$$\dfrac{5}{12}\makebox[0pt][l]{$\,\,\nearrow$}\searrow \dfrac{20}{9}.$$
\end{document}

The code is doing what I want it to do but I am noticing errors, namely

unclosed $$ found at $ unclosed open group { found at $ unexpected $ after open group { unexpected $ after $$ unexpected $ after $$

I can't seem to understand how to resolve this and get the symbol I'm looking for. After some research I learnt about a \toea command but I can't seem to implement this. Any help would be great!

I noticed I haven't included the list of packages I've used in my code but I have all the standard ones you'd expect — Duncan Chrystal, Jul 18 '23 at 23:43
Welcome to TeX.SE. Do also replace \begindocument with \begin{document}, and please peruse and take to heart the posting Why is \[ ... \] preferable to $$ ... $$? — Mico, Jul 18 '23 at 23:57
if you fix ! Undefined control sequence. <recently read> \begindocument you get ! Undefined control sequence. l.3 $$\dfrac the message you do show is not from tex. — David Carlisle, Jul 19 '23 at 00:00

Mico · Accepted Answer · 2023-07-19T06:16:06.033

Assuming these composite arrows will never show up in first- or second-level subscripts or superscripts (or, more generally, while TeX is in \scriptstyle or \scriptscriptstyle math mode), the following solution, which creates a macro called \crossedarrows with the help of the low-level \ooalign command, may be of interest to you.

Note that the definition of \crossedarrows assumes that the new symbol is to be used as a relational operator (hence the \mathrel directive). If, instead, the symbol should be used as a binary operator, you should change \mathrel to \mathbin.

\documentclass{article}
\newcommand\crossedarrows{\mathrel%  % or '\mathbin' ?
    {\ooalign{$\nearrow$\cr$\searrow$}}}
\begin{document}
$\displaystyle \frac{5}{12} \crossedarrows \frac{20}{9} $
\end{document}

Crossed NE and SE arrows?

1 Answers1