A note on the $L^p$ integrability of a class of B\^ochner-Riesz kernels

Abstract

For a general compact variety $\Gamma$ of arbitrary codimension, one can consider the $L^p$ mapping properties of the B\^ochner-Riesz multiplier $$ m_{\Gamma, \alpha}(\zeta) \ = \ {\rm dist}(\zeta, \Gamma)^{\alpha} \phi(\zeta) $$ where $\alpha > 0$ and $\phi$ is an appropriate smooth cut-off function. Even for the sphere $\Gamma = {\mathbb S}^{N-1}$, the exact $L^p$ boundedness range remains a central open problem in Euclidean Harmonic Analysis. In this paper we consider the $L^p$ integrability of the B\^ochner-Riesz convolution kernel for a particular class of varieties (of any codimension). For a subclass of these varieties the range of $L^p$ integrability of the kernels differs substantially from the $L^p$ boundedness range of the corresponding B\^ochner-Riesz multiplier operator.