Quasiextremals for a Radon-like transform
Classical Analysis and ODEs
2011-06-06 v1
Abstract
Convolution with an appropriate surface measure on a paraboloid is known to define a bounded operator T from L^p(R^d) to L^q(R^d) for certain exponents p,q. By a quasiextremal for the associated inequality, we mean a function f for which the norm of Tf is at least a constant c times the norm of f. Our main result characterizes all quasiextremals, with some quantitative control in terms of c. Several related results are also discussed. This is the first in a series of at least four articles about a circle of questions concerning the inverse problem of deducing information about f from information about the ratio of the norm of Tf to the norm of f.
Cite
@article{arxiv.1106.0722,
title = {Quasiextremals for a Radon-like transform},
author = {Michael Christ},
journal= {arXiv preprint arXiv:1106.0722},
year = {2011}
}