“…The existence of at least one solution of this initial value problem has been proved (see [13]) where the function f (t, U) = f (t, u 1 (t), ..., u n (t)) satisfies Caratheodory conditions, i.e., t → f (t, U) is measurable for every U ∈ R n+1 and U → f (t, U) is continuous for every t ∈ I . f (t, U) is nondecreasing for all variables, and there exist a function a(t) ∈ L 1 and constants b k ≥ 0, such that…”