Let $W \in \text{Wiener}(\mu, \sigma)$ be a D3657: Real Wiener process.
Let $t \in [0, \infty)$ be an D4767: Unsigned real number.
Let $t \in [0, \infty)$ be an D4767: Unsigned real number.
Then
\begin{equation}
W_t
\overset{d}{=} \text{Gaussian}(\mu t, \sigma \sqrt{t})
\end{equation}