The object of this paper is to
use the method of product integration to treat the time dependent evolution
equation u′(t) = A(t)(u(t)),t ≧ 0, where u is a function from [0,∞) to a
Banach space S and A is a function from [0,∞) to the set of mappings
(possibly nonlinear) on S. The basic requirements made on A are that for each
t ≧ 0A(t) is the infinitesimal generator of a semi-group of nonlinear nonexpansive
transformations on S and a continuity condition on A(t) as a function of
t.