Laplace-transform formula for a semigroup resolvent
= Laplace-transform formula for a semigroup resolvent
If $A$ generates a <C0-semigroup> satisfying $\|U(t)\|\leq Me^{\omega t}$, then for $\operatorname{Re}z>\omega$ its <resolvent operator> is
$$
(zI-A)^{-1}x=\int_0^\infty e^{-zt}U(t)x\,dt.
$$
Repeated differentiation gives $n!(zI-A)^{-(n+1)}x=\int_0^\infty t^ne^{-zt}U(t)x\,dt$.