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!

## Best Answer

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 theComprehensive LaTeX symbolslist and a web-based software known asDetexify. 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: