A new pair of transformations and applications to generalized informational inequalities and Hausdorff moment problem
Razvan Gabriel Iagar, David Puertas-Centeno
TL;DR
This paper introduces two mutually inverse transformations, the up and down transforms, that map between moments and Rényi/Shannon entropies, as well as between Rényi entropies and generalized Fisher information, thereby creating a mirrored domain for informational inequalities. Using these transforms, the authors extend Stam and moment-entropy inequalities to the mirrored index domain and characterize their minimizers, which are unbounded stretched Gaussian-type densities; they also connect the Hausdorff entropic moment problem to the standard Hausdorff problem and formulate a Fisher-like moment problem. The results yield explicit transformation rules for key quantities, scaling relations, and tail behavior, together with closed-form expressions for transformed minimizers in many parameter regimes. Additionally, the work develops a sharp inequality relating Rényi and Shannon entropies in the mirrored setting and demonstrates how the transformed densities serve as a bridge between entropic reconstruction and moment-based approaches, suggesting robust tools for handling unbounded densities and extended informational bounds with potential applications in MaxEnt frameworks.
Abstract
We introduce a pair of transformations, which are mutually inverse, acting on rather general classes of probability densities in R. These transformations have the property of interchanging the main informational measures such as p-moments, Shannon and Rényi entropies, and Fisher information. We thus apply them in order to establish extensions and generalizations of the Stam and moment-entropy inequalities in a mirrored domain of the entropic indexes. Moreover, with the aid of the two transformations we establish formal solutions to the Hausdorff entropic moment problem by connecting them with the solutions of the standard Hausdorff problem. In addition, we introduce a Fisher-like moment problem and relate it to the standard Hausdorff moment problem.
