Sharp total variation results for maximal functions

Abstract

In this article, we prove some total variation inequalities for maximal functions. Our results deal with two possible generalizations of the results contained in Aldaz and Pérez Lázaro's work, one of whose considers a variable truncation of the maximal function, and the other one interpolates the centered and the uncentered maximal functions. In both contexts, we find sharp constants for the desired inequalities, which can be viewed as progress towards the conjecture that the best constant for the variation inequality in the centered context is one. We also provide counterexamples showing that our methods do not apply outside the stated parameter ranges.