[OS X TeX] Matrix in a subsections's title ?

[Eric van der Oord]

I've put in my preamble :

\usepackage{amsmath,amssymb}
\usepackage{array}
\usepackage[medium,raggedright,md,compact]{titlesec}

%%%

In the document :

[some text]

\subsection{ bla bla $\begin{array}{cc} 1&2\\3&4 \end{array}$}

[some text]

causes the following error :

./Ana-Plan deÃÅtailleÃÅ-2.tex:284: TeX capacity exceeded, sorry [input stack si
ze=5000].
\reserved at a ->\def \reserved at a 
                               *{\ttl at assign@i {\@tempskipb }}\reserved at a 
l.284 ...$\begin{array}{cc} 1&2\\3&4 \end{array}$}
                                                  
./Ana-Plan deÃÅtailleÃÅ-2.tex:284:  ==> Fatal error occurred, no output PDF fil
e produced!


Is that a known issue ? How can I put a matrix in a subsections's title ?


Thanks for any help

Eric