  In this paper, we first use the Bohr property to give a definition of
Besicovitch almost periodic functions, and study some basic properties of
Besicovitch almost periodic functions, including the equivalence of the Bohr
property and the Bochner property. Then, as an application, we use the
contraction principal to obtain the existence and uniqueness of Besicovitch
almost periodic solutions for a class of abstract semi-linear differential
equations with delay.
