In this paper we study an integral equation of the form
175> with resolvent
R(t,s) and variation-of-parameters formula
eba4032">175>. We give a variety of conditions under which the mapping
maps a vector space containing unbounded functions into an
Lp space. It is known from the ideal theory of Ritt that
R(t,s) is arbitrarily complicated. Thus, it is widely supposed that this integral is also extremely complicated. In fact, it is not. That integral can be a very close approximation to
even when
is unbounded. These unbounded functions are essentially harmless perturbations.