How to typeset boldface ell?

Question

I know that \ell gives me this nice mathematical "calligraphic" letter l, which I want to use throughout my document. However, it is also a common typographic convention that vectors are typeset in boldface as opposed to having a little arrow on top of them.

Hence: How do I get a boldface \ell? Simply enclosing it in \mathbf does not work...

Answer 1

You can use \boldsymbol from the amsbsy package; if you are going to use the symbol very often, then you can define a new command, as in the following example:

\documentclass{article}
\usepackage{amsmath,amsbsy}

\newcommand*\Bell{\ensuremath{\boldsymbol\ell}}

\begin{document}

\Bell

\end{document}

Answer 2

\documentclass{article}
\begin{document}

$\ell$\boldmath$\ell$\unboldmath

\end{document}