Logarithmically complete monotonicity of reciprocal ARCTAN function


Vladimir Jovanović, Milanka Treml




We prove the conjecture stated in F. Qi and R. Agarwal, \emph{On complete monotonicity for several classes of functions related to ratios of gamma functions}, J. Inequal. Appl. (2019), that the function $1/\arctan$ is logarithmically completely monotonic on $(0,\infty)$, but not a Stieltjes transform.