2025/11/03 by Mishra, Deepshikha, Swaminathan, A.
#26A48 #26D07 #33B15 #FOS: Mathematics #General Mathematics (math.GM)
paper · doi:10.48550/arxiv.2511.07444
In this manuscript, we present the complete monotonicity of functions defined in terms of the poly-double gamma function ψ2(n)(x) = (-1)n+1 n! ∑k=0∞ \dfrac(1+k)(x+k)n+1, x gt; 0, n≥ 2. Consequently, we derive bounds for the ratio involving ψ2(n)(x) and apply these bounds to establish the convexity, subadditivity and superadditivity of ψ2(n)(x). In the process, various fundamental properties of ψ2(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.