Complete monotonicity of a function involving derivatives of the Barnes G-function
Abstract
In this manuscript, we present the complete monotonicity of functions defined in terms of the poly-double gamma function \begin{align*} ψ_2^{(n)}(x) = (-1)^{n+1} n! \sum_{k=0}^{\infty} \dfrac{(1+k)}{(x+k)^{n+1}}, \quad x > 0, \ n\geq 2. \end{align*} Consequently, we derive bounds for the ratio involving $ψ_2^{(n)}(x)$ and apply these bounds to establish the convexity, subadditivity and superadditivity of $ψ_2^{(n)}(x)$. In the process, various fundamental properties of $ψ_2^{(n)}(x)$ are established, including recurrence relations, integral representations, asymptotic expansions, complete monotonicity, and related inequalities. Graphical illustrations are provided to support the theoretical results.
Fields of Study & Subjects
Mathematical Inequalities and Applications
Analytic and geometric function theory
Mathematical functions and polynomials
Publication details
- Journal / source
- Journal of Inequalities and Applications
- Publisher
- Springer Science and Business Media LLC
- Volume
- 2026
- Issue
- 1
- Publication date
- 23 June 2026
- Language
- EN