Weighted Solyanik Estimates for the Hardy-Littlewood maximal operator and embedding of $A_\infty$ into $A_p$ (1405.6631v2)

Abstract: Let $w$ denote a weight in $\mathbb{R}^n$ which belongs to the Muckenhoupt class $A_\infty$ and let $\mathsf{M}w$ denote the uncentered Hardy-Littlewood maximal operator defined with respect to the measure $w(x)dx$. The \emph{sharp Tauberian constant} of $\mathsf M_w$ with respect to $\alpha$, denoted by $\mathsf{C}_w (\alpha)$, is defined by [ \mathsf{C}_w (\alpha) := \sup{E:\, 0 < w(E) < \infty}w(E)^{-1}w\big(\big{x \in \mathbb{R}^n:\, \mathsf{M}w \chi_E (x) > \alpha\big}\big). ] In this paper, we show that the Solyanik estimate [ \lim{\alpha \rightarrow 1^-}\mathsf{C}_w(\alpha) = 1 ] holds. Following the classical theme of weighted norm inequalities we also consider the sharp Tauberian constants defined with respect to the usual uncentered Hardy-Littlewood maximal operator $\mathsf M$ and a weight $w$: [ \mathsf C ^w (\alpha) := \sup_{E:\, 0 < w(E) < \infty} w(E)^{-1} w\big(\big{x \in \mathbb R^n:\, \mathsf{M} \chi_E (x) > \alpha\big}\big). ] We show that we have $\lim_{\alpha\to 1^{-}}\mathsf{C}^w(\alpha)=1$ if and only if $w\in A_\infty$. As a corollary of our methods we obtain a quantitative embedding of $A_\infty$ into $A_p$.