Semigroup property
= Semigroup property
The semigroup property is $U(t+s)=U(t)U(s)$ for nonnegative times, together with $U(0)=I$. It expresses that evolving for two consecutive intervals is equivalent to evolving for their total duration.
= Semigroup property
The semigroup property is $U(t+s)=U(t)U(s)$ for nonnegative times, together with $U(0)=I$. It expresses that evolving for two consecutive intervals is equivalent to evolving for their total duration.