Math formula changes in tikz environment

Question

I am trying to write a formula in a tikzpicture but it gets changed. The indices for the cumulative product is moved from under the \prod to after. See MWE:

\documentclass{beamer}
\usepackage{tikz}


%%%%%%%%%%%%%%%%%
\begin{document}

\begin{frame}

\begin{center}
\begin{tikzpicture}
\node [font=\bf\tiny] {$1 - \widehat{S}(t) = \prod_{j:t_j \leq t} \frac{d_{kj}}{n_{j}}$};
\end{tikzpicture}
\end{center}

\begin{equation}
1 - \widehat{S}(t) = \prod_{j:t_j \leq t} \frac{d_{kj}}{n_{j}}
\end{equation}

\end{frame}

\end{document}

Any idea why? Any way around?

Answer 1

Has nothing to do with tikZ. You are using the inline mode with $...$ which is typeset in that way. Use

$ ... \prod\limits_{j:t_j \leq t} ... $