Memorylessness of the exponential distribution
= Memorylessness of the exponential distribution
= Memoryless property
{synonym}
If $T\sim\operatorname{Exp}(\mu)$, then
$$
\mathbb P(T>s+t\mid T>s)=\mathbb P(T>t)=e^{-\mu t}.
$$
Thus an exponential remaining lifetime has the same law regardless of the elapsed lifetime.