In this paper, we consider the vector-valued
Laplace transforms,
r-times (
r![](/images/glyphs/BOA.GIF)
[0,∞))
integrated semigroups and regularized semigroups in the context
of sequentially complete locally convex spaces. Our theorems develop the corresponding results in [1,11], including the well known
integrated version of the classical Widder's representation theorem
of Laplace transforms for functions taking values in Banach spaces. Moreover, we study a class
of differential operators on certain function spaces. Optimal conditions, making them the generators
of integrated or regularized semigroups, are obtained. We finally show some applications to abstract Cauchy problems.