English

On Maximal Correlation, Hypercontractivity, and the Data Processing Inequality studied by Erkip and Cover

Information Theory 2013-04-24 v1 math.IT

Abstract

In this paper we provide a new geometric characterization of the Hirschfeld-Gebelein-R\'{e}nyi maximal correlation of a pair of random (X,Y)(X,Y), as well as of the chordal slope of the nontrivial boundary of the hypercontractivity ribbon of (X,Y)(X,Y) at infinity. The new characterizations lead to simple proofs for some of the known facts about these quantities. We also provide a counterexample to a data processing inequality claimed by Erkip and Cover, and find the correct tight constant for this kind of inequality.

Cite

@article{arxiv.1304.6133,
  title  = {On Maximal Correlation, Hypercontractivity, and the Data Processing Inequality studied by Erkip and Cover},
  author = {Venkat Anantharam and Amin Gohari and Sudeep Kamath and Chandra Nair},
  journal= {arXiv preprint arXiv:1304.6133},
  year   = {2013}
}

Comments

11 pages

R2 v1 2026-06-22T00:04:31.784Z