Representation Formulae and Monotonicity of the Generalized k-Bessel Functions

Abstract: This paper introduces and studies a generalization of the $\mathtt{k}$-Bessel function of order $\nu$ given by [\mathtt{W}^{\mathtt{k}}_{\nu, c}(x):= \sum_{r=0}^\infty \frac{(-c)^r}{\Gamma_{\mathtt{k}}\left( r \mathtt{k} +\nu+\mathtt{k}\right) r!} \left(\frac{x}{2}\right)^{2r+\frac{\nu}{\mathtt{k}}}. ] Representation formulae are derived for $\mathtt{W}^{\mathtt{k}}_{\nu, c}.$ Further the function $\mathtt{W}^{\mathtt{k}}_{\nu, c}$ is shown to be a solution of a second order differential equation. Monotonicity and log-convexity properties for the generalized $\mathtt{k}$-Bessel function $\mathtt{W}^{\mathtt{k}}_{\nu, c}$ are investigated, particularly in the case $c=-1$. Several inequalities, including the Tur\'an-type inequality are established.