Comments on the paper "Universal bounds and monotonicity properties of ratios of Hermite and Parabolic Cylinder functions"

Abstract

In the abstract of [1] we read: "We obtain so far unproved properties of a ratio involving a classof Hermite and parabolic cylinder functions." However, we explain how some of the main results in that paper were already proved in [2], namely the `universal bounds'. An error in reference [2] was discussed in [1] which does not affect the proof given there for those `universal bounds'; we fix this erratum easily. We end this note proposing a conjecture regarding the best possible upper bound for a certain ratio of parabolic cylinder functions.