\documentclass{jarticle}
\usepackage{amsmath}

\newcommand{\inlaw}{\mathop{\stackrel{{d}}{\longrightarrow}}}
\newcommand{\inprob}{\mathop{\stackrel{p}{\longrightarrow}}}


\begin{document}

$$
X_n \inlaw X,\ Y_n\inprob Y \quad \text{($n\to\infty$)}
$$

\end{document}
