Bilinear maximal functions associated with degenerate surfaces (2212.11463v1)
Abstract: We study $L{p}\times L{q}\rightarrow L{r}$-boundedness of (sub)bilinear maximal functions associated with degenerate hypersurfaces. First, we obtain the maximal bound on the sharp range of exponents $p,q,r$ (except some border line cases) for the bilinear maximal functions given by the model surface $\big{(y,z)\in\mathbb{R}{n}\times \mathbb{R}{n}:|y|{l_{1}}+|z|{l_{2}}=1\big}$, $(l_{1},l_{2})\in [1,\infty)2$, $n\ge 2$. Our result manifests that nonvanishing Gaussian curvature is not good enough, in contrast with $Lp$-boundedness of the (sub)linear maximal operator associated to hypersurfaces, to characterize the best possible maximal boundedness. Secondly, we consider the bilinear maximal function associated to the finite type curve in $\mathbb R2$ and obtain a complete characterization of the maximal bound. We also prove multilinear generalizations of the aforementioned results.