“…Shift Operators) Let T * be a nonempty subset of the time scale T including a fixed number t 0 ∈ T * such that there exist operators δ ± : [t 0 , ∞) T × T * → T * satisfying the following properties: P 1. The functions δ ± are strictly increasing with respect to their second arguments, i.e., if(T 0 , t), (T 0 , u) ∈ D ± := {(s, t) ∈ [t 0 , ∞) T × T * : δ ± (s, t) ∈ T * } , then T 0 ≤ t < u implies δ ± (T 0 , t) < δ ± (T 0 , u), P.2 If (T 1 , u), (T 2 , u) ∈ D − with T 1 < T 2 , then δ − (T 1 , u) > δ − (T 2 , u),…”