**The problem:**

I get an **undefined control sequence** error when trying to define the bullet type of the second-level items. I'm using:

```
\renewcommand{\labelitemii}{$\centerdot$}

```

**Notes:**

* I've read in some pages (e.g. [Latex symbols](http://latex.wikia.com/wiki/List_of_LaTeX_symbols)) that `\centerdots` is a valid symbol.
* My document compiles fine without that line. It also works fine if I use another type, like `\Rightarrow` or `\cdot`. For example

```
\renewcommand{\labelitemii}{$\cdot$}

```
* The error message is:

```
! Undefined control sequence.
<recently read> \centerdot
l.114 \item C
ontienen los operandos vectoriales en máquinas de registros
The control sequence at the end of the top line
of your error message was never \def'ed. If you have
misspelled it (e.g., `\hobx'), type `I' and the correct
spelling (e.g., `I\hbox'). Otherwise just continue,
and I'll forget about whatever was undefined.

```
* The line which the first error points to is:

```
\begin{itemize} % first level
   \item \textbf{Registros Vectoriales}
   \begin{itemize} % second level
       \item Contienen los operandos vectoriales en máquinas de registros % ERROR
   ...

```