“…has a bounded solution v with inf n∈Z |v(n)| > 0, then there exists a unique f ∈ AP (R, R) and u ∈ AP (Z, R), up to a nonzero multiplicative constant, such that As for impulsive differential equations, Theorems 1.1 and 1.2 indicate the direction of looking for solutions in the factorization form and provide an answer to the almost periodicity of the functions in an assumption (see (A1) below) of [8,9,14,15,19,20]. Changing variables is an important tool in dynamics.…”