Address:
L.M. Navas, Departamento de Matemáticas, Universidad de Salamanca, 37008 Salamanca, Spain
F.J. Ruiz, Departamento de Matemáticas, Universidad de Zaragoza, 50009 Zaragoza, Spain
J.L. Varona, Departamento de Matemáticas y Computación, Universidad de La Rioja, 26006 Logroño, Spain
E-mail:
navas@usal.es
fjruiz@unizar.es
jvarona@unirioja.es
Abstract: One can find in the mathematical literature many recent papers studying the generalized Apostol-Bernoulli, Apostol-Euler and Apostol-Genocchi polynomials, defined by means of generating functions. In this article we clarify the range of parameters in which these definitions are valid and when they provide essentially different families of polynomials. In particular, we show that, up to multiplicative constants, it is enough to take as the “main family” those given by \[ \Big ( \frac{2}{\lambda e^t+1} \Big )^\alpha e^{xt} = \sum _{n=0}^{\infty } \mathcal{E}^{(\alpha )}_{n}(x;\lambda ) \frac{t^n}{n!}\,, \qquad \lambda \in \mathbb{C}\setminus \lbrace -1\rbrace \,, \] and as an “exceptional family” \[ \Big ( \frac{t}{e^t-1} \Big )^\alpha e^{xt} = \sum _{n=0}^{\infty } \mathcal{B}^{(\alpha )}_{n}(x) \frac{t^n}{n!}\,, \] both of these for $\alpha \in \mathbb{C}$.
AMSclassification: primary 11B68; secondary 05A15.
Keywords: Bernoulli polynomials, Nørlund polynomials, Apostol-Bernoulli polynomials, Apostol-Euler polynomials, Apostol-Genocchi polynomials, generating functions, Appell sequences.
DOI: 10.5817/AM2019-3-157