[Tex/LaTex] Problems with ‘\rightrightarrows’ and other a arrow symbols

Question

I'm trying to define a mathematical correspondence. The double-arrow symbol is supposed to be \rightrightarrows. But when I run it LaTex tells me that it is not defined. This also happens with other arrow symbols (like \circlearrowleft) that are supposed to be available.

Can anyone help me? Do you know if I need a package for those symbols?
Thanks in advance!

Answer 1

Finding a particular LaTeX symbol or character can be very easy. Have a look at “How to look up a math symbol?” for ideas on how you can achieve this. The linked question lists two especially helpful tools; namely the Comprehensive LaTeX symbols list and a web-based software known as Detexify. The latter is also available for smart phones.

If you try one of the above tools, you will discover that the symbols you need require using the amssymb package. Here are some examples:

\documentclass{article} 
\usepackage{amssymb} 
\begin{document} 

\begin{tabular}{ccc}
$\circlearrowleft$  & $\leftleftarrows$      & $\rightleftarrows$     \\
$\circlearrowright$ & $\leftrightarrows$     & $\rightrightarrows$    \\
$\curvearrowleft$   & $\leftrightsquigarrow$ & $\rightsquigarrow$     \\
$\curvearrowright$  & $\Lleftarrow$          & $\Rsh$                 \\
$\dashleftarrow$    & $\looparrowleft$       & $\twoheadleftarrow$    \\
\end{tabular}

\end{document}