What font is this?

Can anyone tell me where the script L in the following snippet comes from? It's not \mathcal{L}:

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possible duplicate of How do I find out what fonts are used in a document/picture? –  Loop Space Aug 16 '12 at 8:39

The mathrsfs package provides \mathscr for script mathematical letters, rather than redefining \mathcal:

\documentclass{article}
\usepackage{mathrsfs}% http://ctan.org/pkg/mathrsfs
\begin{document}
$\mathscr{L}u$
\end{document}


Also consider reading this entry on the UK TeX FAQ: Better script fonts for maths.

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Thanks. (I keep forgetting about the TeX FAQ. I should stop doing that.) –  rogerl Aug 28 '11 at 16:42