  The paper introduces the notion of skew-evolution semiflows and presents the
concept of pointwise trichotomy in the case of skew-evolution semiflows on a
Banach space. The connection with the classic notion of trichotomy presented by
us in a previous paper in 2006 for evolution operators, is also emphasized, as
well as some characterizations. The approach of the theory is from uniform
point of view. The study can also be extended to systems with control whose
state evolution can be described by skew-evolution semiflows.
