On the Two-Weight Problem for One-Sided Maximal Operators in Higher Dimensions

RESUMO

For the one-sided Hardy--Littlewood maximal operator $M_d^+$ on $\mathbb R^d$, the natural two-weight Muckenhoupt condition was shown by Sawyer in 1986 to characterize the weak $(p,p)$ inequality in dimension one, and by Forzani, Martín-Reyes and Ombrosi in 2011 in dimension two. At the endpoint $p=1$ in dimension three, Ombrosi and Nazarov have recently given negative answers to both the Fefferman--Stein-type question and the related weighted weak-type $(1,1)$ question \cite{OmbrosiNazarov} (personal communication). In this paper, we prove that the two-weight characterization fails for every $d\geq 3$ and $p>1$. More precisely, for every $1<p<\infty$ and every $d\geq 3$, there exist weights $w$ and $v$ such that $$ A_{p,d}^+(w,v)<\infty, \qquad \|M_d^+\|_{L^p(v)\to L^{p,\infty}(w)}=\infty. $$ The proof uses a finite two-dimensional Hardy operator whose weak operator norm is bounded below by $c_p(\log N)^{1/p'}$. This operator is embedded into the three-dimensional lattice maximal operator and then transferred to the continuous setting. A tensor extension yields the same failure in every dimension $d>3$.