“…They are generalizations of the classical Bernoulli, Euler and Genocchi polynomials B n (x), E n (x) and G n (x), that correspond to the cases λ = 1 and α = 1 (moreover, the so-called Bernoulli, Euler and Genocchi numbers are B n = B n (0), E n = 2 n E n ( 1 2 ) and G n = G n (0)). In the mathematical literature, the parameters α and λ have been included independently (we give some historical details in Subsection 1.1); once the parameters have been used together, the definitions (1), (2) and (3) have been extended to α ∈ C. The goal of this paper is to clarify when this extension is possible (Subsection 1.2), and to reduce the above-mentioned definitions with complex λ and α to a smaller class of polynomials that suppresses the trivial relationships between them (Section 2, see 7, (8) and Definition 4). Except for multiplicative constants, our reduction covers every case of generalized Apostol-Bernoulli, Apostol-Euler and Apostol-Genocchi polynomials without the necessity of adding extra parameters.…”