I was going to write along an arc some math expression with curly brackets. Somehow the following snippet causes pdflatex to freeze.
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{decorations}
\usetikzlibrary{decorations.text}
\begin{document}
\begin{tikzpicture}
\draw[->,blue,
postaction={decorate,decoration={text along path, raise=4pt,
text={ $\{ hello \}${} },text color=blue,
text align={align=center}}}] (0,5) arc (90:0:5);
\end{tikzpicture}
\end{document}
How can I do it otherwise?


decoration={text along path, text align=center, text={${\overline{s}}${}}, raise=18pt}– feculededentier Mar 02 '15 at 16:05{$T_r${}}). Instead, try:{{$T_r$}{}}. – Rico Picone Apr 19 '17 at 08:00