Let S be a real Banach space.
Let C denote the infinitesimal generator of a strongly continuous semigroup T of
bounded linear transformations on S. This paper presents a construction which
proves that for each b > 1 there is a dense subset D(b) of S so that if p is in D(b),
then
(A) p is in the domain of Cn for all positive integers n and
(B) limn→∞∥Cnp∥(n!)−b = 0.
Condition (B) will be used in §3 to obtain series solutions to the partial
differential equations U12 = CU and U11 = CU.
|